| Volume 6 -- Issue 6 | March 1986 |
In This Issue...
ES-CAPE
Whatever happened to the Extended S-C Applesoft Program Editor? That's a question we've heard more than a few times in the last year or two, and we finally have some kind of answer.
We got bogged down in producing Version 2.0 of the program. The new printer control, Park and Join, and Applesoft and DOS command features are great. The 40-column, STB-80, and //e versions came out just fine, but the Videx and Viewmaster versions stumped us. The planned Renumber and Merge features never made it, and we couldn't settle on a mechanism for adding other utility programs.
Anyway, we've got a deal for you! How's this for a package?: ES-CAPE 1.0 Source and Object Code and manual, along with ES-CAPE 2.0 Source and Object Code and a manual supplement on disk. That's all the source and object code for both versions of the program, for a total of only $50.00. Registered owners of ES-CAPE 1.0 can purchase this new package for only $30.00.
New 65816 Book
There's another book coming along on programming the 658xx processors. This one is called "65816/65802 Assembly Language Programming", by Michael Fischer, published by Osborne/ McGraw-Hill as an addition to their Assembly Language Programming series, mostly by Lance Leventhal. Fischer's book is scheduled for May delivery, so we have ordered some copies and are beginning to accept orders. Our price will be $18.00 + shipping.
| Modifying ProDOS for Non-Standard ROMs | Bob Sander-Cederlof |
We have published several times ways to defeat the ROM Checksummer that is executed during a ProDOS boot, so that owners of Franklin clones (or even real Apples with modified monitor ROMs) could use ProDOS-based software. See AALs of March and June, 1984.
Both of these previous articles are out of date now, because they apply to older versions of ProDOS than are current. What follows applies to Version 1.1.1 of ProDOS.
There are two problems with getting ProDOS to boot on a non-standard machine. The first is the ROM Checksummer. This subroutine starts at $267C in Version 1.1.1, and is only called from $25EE. The code is purposely weird, designed to look like it is NOT checking the ROMs. It also has apparently purposeful side effects. Here is a listing of the subroutine:
1000 *SAVE CHECKSUMMER 1010 *-------------------------------- 1020 .OR $267C POSITION IN PRODOS SYSTEM FILE 1030 *-------------------------------- 1040 CHECKSUMMER 1050 CLC 1060 LDY $2674 (GETS A VALUE 0) 1070 .1 LDA ($0A),Y GETS (FB09...FB10) 1080 AND #$DF STRIP OFF LOWER CASE BIT 1090 ADC $2674 ACCUMULATE SHIFTED SUM 1100 STA $2674 1110 ROL $2674 SHIFT RESULT, CARRY INTO BIT 0 1120 INY 1130 CPY $2677 DO IT 8 TIMES 1140 BNE .1 1150 TYA A = Y = 8 1160 ASL FORM $80 BY SHIFTING 1170 ASL 1180 ASL 1190 ASL 1200 TAY $80 TO Y FOR LATER TRICK 1210 EOR $2674 MERGE WITH PREVIOUS "SUM" 1220 ADC #11 FORM $00 FOR VALID ROMS 1230 BNE .2 ...NOT A VALID ROM 1240 LDA $0C GET MACHINE ID BYTE 1250 RTS 1260 .2 LDA #0 SIGNAL INVALIDITY 1270 RTS |
The pointer at $0A,0B was set up to point to $FB09 using very sneaky code at $248A. Location $2674 initially contains a 0, and $2677 contains an 8. Only the bytes from $FB09 through $FB10 are checksummed. Truthfully, "checksummed" is not the correct word.
The wizards who put ProDOS together figured out a fancy function which changes the 64 bits from $FB09 through $FB10 into the value $75. Their function does this whether your ROMs are the original monitor ROM from 1977-78, the Autostart ROM, the original //e ROM, or any other standard Apple ROM. The values in $FB09-FB10 are not the same in all cases, but the function result is always $75. However, a Franklin ROM does not produce $75. Probably a BASIS also gives a different result, and other clones. Once $75 is obtained, further slippery code changes the value to $00.
The original Apple II ROM has executable code at $FB09, and in hex it is this: B0 A2 20 4A FF 38 B0 9E. All other Apple monitor ROMs have an ASCII string at $FB09. The string is either "APPLE ][" or "Apple ][". Notice that the "AND #$DF" in the checksummer strips out the upper/lower case bit, making both ASCII strings the same.
I wrote a test program to print out all the intermediate values during the "Checksummer's" operation. Here are the results, for both kinds of ROMs.
Original ROM Later ROMs
LDA AND ADC STA ROL LDA AND ADC STA ROL
B0 90 00 90 20 C1 C1 00 C1 82
A2 82 20 A2 44 D0/F0 D0 82 52 A5
20 00 44 44 88 D0/F0 D0 A5 75 EB
4A 4A 88 D2 A4 CC/EC CC EB B7 6F
FF DF A4 83 07 C5/E5 C5 6F 34 69
38 18 07 1F 3E A0 80 69 E9 D2
B0 90 3E C3 9C DD DD D2 AF 5F
9E 9E 9C 3A 75 DB DB 5F 3A 75
I don't understand why this code gives the same result, but I see it does. Now, dear readers, tell me how anyone ever figured out what sequence of operations would produce the same result using these two different sets of eight bytes, and yet produce a different result for clones! If you understand it, please explain it to me!
By the way, here is a listing of my test program:
1000 .LIF 1010 *SAVE TEST.CKSUMMER 1020 *-------------------------------- 1030 * SIMULATE PRODOS $FB09-FB10 CHECK-SUMMER 1040 * (AT $267C IN PRODOS 1.1.1) 1050 *-------------------------------- 1060 T 1070 LDA #S1 1080 STA $0A 1090 LDA /S1 1100 STA $0B 1110 JSR CS 1120 LDA #S2 1130 STA $0A 1140 LDA /S2 1150 STA $0B 1160 CS 1170 JSR PT 1180 CLC 1190 LDY #0 1200 STY X 1210 .1 LDA ($0A),Y 1220 JSR B 1230 AND #$DF 1240 JSR B 1250 LDA X 1260 JSR B 1270 LDA ($0A),Y 1280 AND #$DF 1290 ADC X 1300 STA X 1310 JSR B 1320 ROL X 1330 LDA X 1340 JSR B 1350 JSR $FD8E 1360 INY 1370 CPY #8 1380 BCC .1 1390 TYA 1400 ASL 1410 ASL 1420 ASL 1430 ASL 1440 ORA X 1450 JSR B 1460 ADC #$0B 1470 *-------------------------------- 1480 B PHA 1490 PHP 1500 JSR $FDDA 1510 LDA #" " 1520 JSR $FDED 1530 JSR $FDED 1540 PLP 1550 PLA 1560 RTS 1570 *-------------------------------- 1580 X .BS 1 1590 *-------------------------------- 1600 S1 .AS -/APPLE ][/ 1610 S2 .HS B0.A2.20.4A.FF.38.B0.9E 1620 *-------------------------------- 1630 TITLE .HS 8D8D 1640 .AS -/LDA AND ADC STA ROL/ 1650 .HS 8D00 1660 *-------------------------------- 1670 PT 1680 LDY #0 1690 .1 LDA TITLE,Y 1700 BEQ .2 1710 JSR $FDED 1720 INY 1730 BNE .1 1740 .2 RTS 1750 *-------------------------------- |
The checksummer can be defeated. The best way, preserving the various side effects, is to change the byte at $269F from $03 to $00. This changes the BNE to an effective no-operation, because it will branch to the next instruction regardless of the status. Another way to get the same result is to store $EA at both $269E and $269F. Still another way is to change the "LDA #0" at $26A3,4 to "LDA $0C" (A5 0C), so that either case gives the same result.
If it thinks it is in a valid Apple computer, the checksummer returns a value in the A-register which is non-zero, obtained from location $0C. The value at $0C has been previously set by looking at other locations in the ROM, trying to tell which version is there. Part of this code is at $2402 and following, and part is at $2047 and following. The byte at $0C will eventually become the Machine ID byte at $BF98 in the System Global Page, so it also gets some bits telling how much RAM is available, and whether an 80-column card and a clock card are found.
If you have a non-standard Apple or a clone the bytes which are checked to determine which kind of ROM you have may give an illegal result. The following table shows the bytes checked, and the resulting values for $0C. The values in parentheses are not ever checked, but I included them for completeness. The value in $0C will be further modified to indicate the amount of RAM found and the presence of a clock card.
Version FBB3 FB1E FBC0 FBBF $0C Original Apple II 38 (AD) (60) (2F) 00 Autostart, II Plus EA AD (EA) (EA) 40 Original //e 06 (AD) EA (C1) 80 Enhanced //e 06 (AD) E0 (00) 80 DEBUG //e 06 (AD) E1 (00) 80 Original //c 06 (4C) 00 FF 88 //c Unidisk 3.5 06 (4C) 00 00 88 /// Emulating II EA 8A (??) (??) C0
By the way, ProDOS 1.1.1 will not allow booting by an Apple /// emulating a II Plus, possibly because the standard emulator only emulates a 48K machine.
I have no idea what a clone would have in those four locations, but chances are it would be different. You should probably try to fool ProDOS into thinking you are in a II Plus, because most clones are II Plus clones. This means you should somehow change the ID procedures so that the result in $0C is a value of $40. One way to do this is change the code at $2402 and following like this:
Standard Change to
2402- A9 00 LDA #0 2402- A9 40 LDA #$40
2404- 85 0C STA $0C 2404- 4C 2E 24 JMP $242E
2406- A3 B3 FB LDX $FBB3
If your clone or modified ROM is a //e, change $2402 to LDA #$80 instead.
You may also need to modify the code at $2047 and following. If you are trying to fool ProDOS into thinking you are an Apple II Plus or //e, and have already made the change described above, change $2047-9 like this:
Standard Change to
2047- AE B3 FB LDX $FBB3 2047- 4C 6D 20 JMP $206D
No doubt future versions of ProDOS will make provision for clones and modified ROMs even more difficult. And there are always the further problems encountered by usage of the ROMs from BASIC.SYSTEM and the ProDOS Kernel and whatever application program is running.
I am intrigued about seeing what the minimum amount of code is that can distinguish between the four legal varieties of ROM for ProDOS. I notice from the table above that I can identify the four types and weed out the ///emulator by the following simple code at $2402:
LDA $FBB3
ORA $FB1E
LDX #3
.1 CMP TABLE.1,X
BEQ .2
DEX
BPL .1
SEC
RTS
*
TABLE.1 .HS BD.EF.AF.4E
TABLE.2 .HS 00.40.80.88
*
.2 LDA TABLE.2,X
JMP $242E
With this code installed, all the code from $2047-$206C is not needed, and the JMP $206E should be installed at $2047. The new code at $2402 fits in the existing space with room to spare. Can you do it with even shorter code?
| Even Faster 65802 16x16 Multiply | Bob Sander-Cederlof |
Bob Boughner, faithful reader from Yorktown, Virginia, decided that the challenge at the end of my article in the January 1986 AAL could not be ignored. He was able to slightly increase the speed of my 16x16 multiply subroutine for the 65802. After studying his code, I made a few more little changes and squeezed out even more cycles.
To see just how much faster the new subroutine is, I carefully counted the cycles, and then went back and did the same to January's subroutine. For some reason I got a new answer for January's program, slightly slower than published. Here are the results:
Minimum Maximum Average
January 333 693 513
New One 321 633 477
The times include 6 cycles for a JSR to call the subroutine, and 6 cycles for the RTS to return. By putting the code in-line, even these 12 cycles could be eliminated. The so-called average time is merely the arithmetic average of the minimum and maximum times. The "real" average for random factors will be faster, because one or both of the INC instructions at lines 1350 and 1430 would be skipped. In fact, almost always at least one would be skipped, saving 48 cycles. Note also that if the factor in CAND is zero, the total time is only 45 cycles.
In counting cycles I assumed that the D-register, which tells the 65802 where the direct page is, has a low byte = 0. If it is non-zero, all of the references to CAND, PLIER, and PROD would require one more cycle.
The new subroutine is only 4 bytes longer than the January one. The new one uses the Y-register, while the old one did not. There are three tricks in the new code which save time. The first one is holding the multiplicand in the Y-register, so that TYA instructions can be used at lines 1310 and 1390. This saves 2 cycles each time, or a total of 32 cycles in the maximum case. The cost is the LDY CAND in line 1200, 4 cycles.
The second trick eliminates the CLC instruction before the multiplier is added in lines 1370-1430. The savings is 16 cycles maximum, and the cost is 8 cycles to set it up in lines 1120-1140 by inverting the high byte of the multiplier. This doesn't affect the average time any, but it does lower the maximum time.
The third trick is at lines 1280 and 1290. I saved 24 cycles by eliminating January's AND ##$0080 instruction here. The LDA PLIER-1 instruction picks up the low byte of the multiplier in the high byte of the A-register, allowing me to see what bit 7 of the multiplier is without any masking or shifting.
1000 .OP 65802 1010 *SAVE BOUGHNERS.MULT 1020 *-------------------------------- 1030 * CONTRIBUTED BY BOB BOUGHNER 1040 * MODIFIED A LITTLE MORE BY BOB S-C 1050 *-------------------------------- 1060 CAND .EQ 0,1 1070 PLIER .EQ 2,3 1080 PROD .EQ 4,5,6,7 1090 *-------------------------------- 1100 MUL.FASTER.YET.16X16.65802 1110 LDX #8 WILL LOOP 8 TIMES 1120 LDA PLIER+1 INVERT HIGH BYTE 1130 EOR #$FF TO SAVE "CLC" IN LOOP 1140 STA PLIER+1 1150 CLC 1160 XCE ENTER "NATIVE" MODE 1170 REP #$30 16-BITS BOTH X & M 1180 STZ PROD CLEAR PRODUCT 1190 STZ PROD+2 1200 LDY CAND MULTIPLICAND IN Y-REG 1210 BNE .2 ...NON-ZERO, START LOOP 1220 XCE ...ZERO, EXIT NOW 1230 RTS 1240 *-------------------------------- 1250 .1 ASL PROD DOUBLE THE PRODUCT 1260 ROL PROD+2 1270 *-------------------------------- 1280 .2 LDA PLIER-1 GET LOW BYTE IN A(15-8) 1290 BPL .3 ...ORIG. BIT=0, DON'T ADD 1300 CLC 1310 TYA ...ORIG. BIT=1, ADD 'CAND 1320 ADC PROD 1330 STA PROD 1340 BCC .3 1350 INC PROD+2 ADD CARRY TO HI-16 1360 *-------------------------------- 1370 .3 ASL PLIER SHIFT MULTIPIER, GET HI-BIT 1380 BCS .4 ...ORIG. BIT=0, DON'T ADD 1390 TYA ...ORIG. BIT=1, ADD 'CAND 1400 ADC PROD+1 ADD TO MIDDLE OF PRODUCT 1410 STA PROD+1 1420 BCC .4 1430 INC PROD+3 (NEVER BOTHERS PROD+4) 1440 *-------------------------------- 1450 .4 DEX 1460 BNE .1 1470 SEC 1480 XCE 1490 RTS 1500 *-------------------------------- 1510 .LIF |
| Some More Rumors | Bob Sander-Cederlof |
Electronics magazine printed a brief news item about a second source for 65816 chips. Western Design has signed up a lot of licensees to make these chips, but none of them are in production as of this month. Electronics says VLSI Technology Inc., of San Jose, California, is projecting prices in the $10 range for volume purchases. When? Target is to start selling sample quantities next summer. Meanwhile, volume prices are in the $35 range from Western Design Center. The single-unit price is still about $100.
The parts we are selling are the 65C802 from Western Design Center. Our price to you is $50 each. These are normally spec'd at 2MHz, but sometimes we get 4MHz parts at the same price, when they are out of the slower ones. Either speed works equally well in an Apple motherboard, but you need the 4MHz chip to use in a Transwarp accelerator card.
Rumors continue to ricochet around the club newsletter circuit about the possible configuration of the new Apple II (usually called the //x). Most rumor sources agree now that the //x will use a 65C816. We sure HOPE so! One source said he looks for an 8MHz clock. We doubt that, because current projections are for 8MHz chips becoming available about 1st quarter 1987. And the RAM for 8MHz operation would be far too expensive. My guess we will see either 2MHz or 3.58MHz.
Most are now including a SCSI port in their list of features, since the Macintosh Plus has one. Some are talking about a smaller set of normal slots, supplemented by some new super-slots having more signals available. There are reportedly a number of different versions of the //x already in existence, seeded around. If that is true, it could be than no one (even inside Apple) yet knows what the REAL //x will be.
| Add Smarts to 65816 Dis-Assembler | Jim Popenoe |
I found fascinating the article by Bob Sander-Cederlof in the March 1985 AAL, entitled "A Disassembler for the 65816". I purchased AAL Quarterly Disk 18 and tried it out for myself, watching 65802 instructions zip before my eyes.
But, whoa! Bob was correct in warning that his disassembler would not know whether immediate-mode instructions are two or three bytes long. Bob explained "only by executing the programming, and tracing it line-by-line, can we tell." A fully accurate disassembler for the 65816 would have to execute the equivalent of STEP and TRACE, following the logic flow of the program.
I wanted an easier, quick-and-dirty way to spiff up the output, one that would at least recognize simple, straightforward changes in the processor status. I reasoned that:
1) Interpretation of immediate-mode instructions depends on the state of E, M, and X bits in the status register.
2) E and C bits are exchangeable.
3) The disassembler must keep track of all four bits (C, E, X, and M) in order to disassemble immediate mode opcodes correctly.
4) The disassembler should also keep track of when the processor status is pushed onto or pulled off the stack.
My implementation assigns a memory location for the E-bit, and a small "stack" of 8 memory locations for the status register. One more memory location serves as the stack pointer. Here is the initialization code for these memory locations, replacing lines 1450-1480 in Bob's March 1985 listing:
1450 LDX #$FF START WITH E=1 1454 STX E.BIT 1458 STX STATUS.STACK EMPTY THE STATUS STACK 1462 INX X=0 1466 STX STATUS.PNTR 1470 RTS 1474 *-------------------------------- 1478 E.BIT .BS 1 1482 STATUS.PNTR .BS 1 1486 STATUS.STACK .BS 8 |
I added a JSR TEST.OP.CODES line at 5865, to call some new code which looks for CLC, SEC, REP, SEP, PHP, PLP, and XCE instructions. It adjusts the flags appropriately in response to these instructions. If the current opcode is none of the above, TEST.OP.CODES checks the status bits and the opcode to set up the correct immediate-mode length. If the opcode is an immediate mode operation on the A-register, and if E=0 and M=0, then 16-bit immediate will be disassembled. If the opcode is an immediate mode operation on the X- or Y-register, and if E=0 and X=0, then 16-bit immediate will be disassembled. Otherwise, any kind of immediate mode instruction will be disassembled with an 8-bit operand.
I tried the program on all the sample 65802 code I could find, and it was all disassembled correctly. Of course it is certainly possible to fool my program. The C-bit, and hence possibly the E-bit, can be changed in many other ways than by using the CLC and SEC instructions. The program flow is not followed, so it is possible than my emulation of the carry status and the XCE will not agree with what happens in some code. If you adhere to the "nice" standard of always using explicit SEC or CLC opcodes before an XCE opcode, the disassembler should stay in step perfectly.
When you type 800G to link in the disassembler (refer to Bob's article to know what I mean here) the status is initialized to E=C=M=X=1. This means normal 6502 mode. If you disassemble some code with XCE's in it, the status I keep will probably be left in some other mode. If you then try to disassemble some plain vanilla 6502 code, the immediate instructions may be disassembled with 16-bit operands. Just type 800G again to get back to normal.
By the way, in working with Bob's disassembler I discovered a typing error in his code. Line 3980 was originally >OXA TAY, and it should have been >OXA DEY. The hex listing in Bob's article showed $AF stored in $963; it really should be $89. Without this change, the DEY opcode disassembles as TAY!
The listing that follows has been extensively modified by Bob, based on my code I sent him last September. The lines are numbered to follow after the last line of the program on the quarterly disk.
7060 *-------------------------------- 7070 TEST.OP.CODES 7080 PHA SAVE OPCODE 7090 LSR IMM.SIZE ASSUME 8-BIT IMMEDIATE 7100 LDX STATUS.PNTR 7110 CMP #$18 CLC? 7120 BEQ CLC.OP 7130 CMP #$38 SEC? 7140 BEQ SEC.OP 7150 INY 7160 CMP #$C2 REP? 7170 BEQ REP.OP 7180 CMP #$E2 SEP? 7190 BEQ SEP.OP 7200 DEY 7210 CMP #$08 PHP? 7220 BEQ PHP.OP 7230 CMP #$28 PLP? 7240 BEQ PLP.OP 7250 CMP #$FB XCE? 7260 BEQ XCE.OP 7270 *-------------------------------- 7280 AND #$1F ORA, AND, EOR, ADC, BIT, LDA, CMP, SBC? 7290 CMP #$09 7300 PHP SAVE ANSWER 7310 LDA #$20 ASSUME M-BIT 7320 PLP GET PREVIOUS ANSWER 7330 BEQ .1 IT IS M-BIT 7340 LSR (LDA #$10) USE X-BIT INSTEAD 7350 .1 AND STATUS.STACK,X 7360 BNE .2 ...USE 8-BIT IMMEDIATE 7370 LDA E.BIT 7380 LSR 7390 BCS .2 E=1, USE 8-BIT IMMEDIATE 7400 LDA #$FF ...USE 16-BIT IMMEDIATE 7410 STA IMM.SIZE 7420 .2 PLA GET OPCODE AGAIN 7430 RTS 7440 *-------------------------------- 7450 CLC.OP LDA STATUS.STACK,X 7460 AND #$FE 7470 UPDATE.STATUS 7480 STA STATUS.STACK,X 7490 PLA 7500 RTS 7510 *-------------------------------- 7520 SEC.OP LDA STATUS.STACK,X 7530 ORA #$01 7540 BNE UPDATE.STATUS ...ALWAYS 7550 *-------------------------------- 7560 REP.OP LDA (PCL),Y LOOK AT OPERAND 7570 EOR #$FF 7580 AND STATUS.STACK,X 7590 JMP UPDATE.STATUS 7600 *-------------------------------- 7610 SEP.OP LDA (PCL),Y 7620 ORA STATUS.STACK,X 7630 JMP UPDATE.STATUS 7640 *-------------------------------- 7650 PHP.OP LDA STATUS.STACK,X 7660 INX 7670 CPX #8 7680 BCC PHP.PLP 7690 LDX #0 7700 PHP.PLP 7710 STX STATUS.PNTR 7720 JMP UPDATE.STATUS 7730 *-------------------------------- 7740 PLP.OP DEX 7750 BPL PHP.PLP 7760 LDX #7 7770 BEQ PHP.PLP 7780 *-------------------------------- 7790 XCE.OP LSR E.BIT GET E-BIT INTO CARRY 7800 PHP SAVE IT 7810 LDA STATUS.STACK,X 7820 STA E.BIT NEW E-BIT 7830 LSR C-BIT INTO CARRY 7840 BCC .1 ...NEW E-BIT = 0 7850 ORA #$18 ...NEW E-BIT=1, SO SET M=X=1 7860 .1 PLP GET NEW C-BIT (OLD E-BIT) 7870 ROL PUT IT INTO STATUS BYTE 7880 JMP UPDATE.STATUS |
Further notes by Bob Sander-Cederlof:
Thanks, Jim! Your ideas were a big help! In looking back over my work, I noticed some more improvements.
R. F. O'Brien wrote us just this week with the news that he had found two bugs in the disassembler. One was the typing error at line 3980 which Jim noted above. But Robert found a second typo, at line 4960. ">OXB LDX" should be changed to ">OXB CPX". This changes the byte shown in the original article at $9BF from $19 to $0F.
I found a way to simplify the >ON macro, which speeds up assembly and shortens the listing. Replace lines 1220-1290 with the following:
1220 .MA ON 1280 ]1]2]3]4 .DA ']1-64*32+']2-64*32+']3-64*2 1290 .EM |
I also discovered that one kind of Apple monitor ROM did not have the RELADR subroutine, so I re-coded lines 6760-6950. Replace those lines with the following:
6760 *---8- OR 16-BIT RELATIVE-------- 6770 LDA (PCL),Y 8=OFFSET, 16=OFFSETHI 6780 DEY TEST LENGTH 6790 STY FORMATH =0 IF 8-BIT 6800 BEQ .10 ...8-BIT 6810 STA FORMATH ...16-BIT 6820 LDA (PCL),Y LOW BYTE OF 16-BIT OFFSET 6830 .10 STA FORMATL 6840 JSR PCADJ 6850 CLC 6860 ADC FORMATL 6870 TAX 6880 TYA 6890 ADC FORMATH 6900 JMP PRNTAX |
One last item. I wrote a test routine to call the disassembler for every possible opcode from 00 to FF. Here it is:
7890 *-------------------------------- 7900 TT LDY #0 7910 LDA #$C0 7920 STA PCL 7930 LDA #2 $2C0...$3C3 7940 STA PCH 7950 .1 TYA 7960 STA $2C0,Y 7970 INY 7980 BNE .1 7990 STY $3C0 8000 INY 8010 STY $3C1 8020 INY 8030 STY $3C2 8040 .2 JSR INSTDSP 8050 LDY #0 8060 LDA (PCL),Y 8070 CMP #$FF 8080 BEQ .3 8090 .4 LDA $C000 8100 BPL .4 8110 STA $C010 8120 INC PCL 8130 BNE .2 8140 INC PCH 8150 BNE .2 ...ALWAYS 8160 .3 RTS 8170 *-------------------------------- |
Here is the entire program with my changes included:
1 .LIST OFF 800 .TI 76,65816 DISASSEMBLER.................FEBRUARY 14, 1985........... 810 *SAVE S.816.DSM.NEW 820 *-------------------------------- 830 .OR $300 840 .OP 65816 850 LDA #3 860 SEC 870 LDA #3 880 CLC 890 LDA #3 900 REP #$30 910 LDA #3 920 CLC 930 XCE 940 LDA ##$EA34 950 REP #$20 960 LDA ##$EA34 970 LDX ##$EA34 980 REP #$10 990 LDA ##$EA34 1000 LDX ##$EA34 1010 SEP #$30 1020 .OR $800 1030 *-------------------------------- 1040 IMM.SIZE .EQ $00 1050 LMNEM .EQ $2C 1060 RMNEM .EQ $2D 1070 FORMATL .EQ $2E 1080 LENGTH .EQ $2F 1090 FORMATH .EQ $30 1100 PCL .EQ $3A 1110 PCH .EQ $3B 1120 *-------------------------------- 1130 SCRN2 .EQ $F879 1140 PRNTAX .EQ $F941 1150 PRBLNK .EQ $F948 1160 PRBL2 .EQ $F94A 1170 PCADJ .EQ $F953 1180 CROUT .EQ $FD8E 1190 PRBYTE .EQ $FDDA 1200 COUT .EQ $FDED 1210 *-------------------------------- 1211 .LIST ON 1220 .MA ON 1280 ]1]2]3]4 .DA ']1-64*32+']2-64*32+']3-64*2 1290 .EM 1291 .LIF 1300 *-------------------------------- 1310 .MA OXA 1320 .DA #]1-OPNAMES.A/2+128 1330 .EM 1340 *-------------------------------- 1350 .MA OXB 1360 .DA #]1-OPNAMES.B/2 1370 .EM 1380 *-------------------------------- 1390 T LDA $C083 WRITE-ENABLE RAM COPY OF MONITOR 1400 LDA $C083 1410 LDA #INSTDSP PATCH L-COMMAND TO USE MY 1420 STA $FE65 DIS-ASSEMBLER 1430 LDA /INSTDSP 1440 STA $FE66 1444 .LIST ON 1450 LDX #$FF START WITH E=1 1454 STX E.BIT 1458 STX STATUS.STACK EMPTY THE STATUS STACK 1462 INX X=0 1466 STX STATUS.PNTR 1470 RTS 1474 *-------------------------------- 1478 E.BIT .BS 1 1482 STATUS.PNTR .BS 1 1486 STATUS.STACK .BS 8 1488 .LIST OFF 1490 *-------------------------------- 1500 OPNAMES.A 1510 >ON A,S,L,A 1520 >ON B,R,K 1530 >ON C,L,C 1540 >ON C,L,D 1550 >ON C,L,I 1560 >ON C,L,V 1570 >ON C,O,P 1580 >ON D,E,C,A 1590 >ON D,E,X 1600 >ON D,E,Y 1610 >ON I,N,C,A 1620 >ON I,N,X 1630 >ON I,N,Y 1640 >ON L,S,R,A 1650 >ON N,O,P 1660 >ON P,H,A 1670 >ON P,H,B 1680 >ON P,H,D 1690 >ON P,H,K 1700 >ON P,H,P 1710 >ON P,H,X 1720 >ON P,H,Y 1730 >ON P,L,A 1740 >ON P,L,B 1750 >ON P,L,D 1760 >ON P,L,P 1770 >ON P,L,X 1780 >ON P,L,Y 1790 >ON R,O,L,A 1800 >ON R,O,R,A 1810 >ON R,T,I 1820 >ON R,T,L 1830 >ON R,T,S 1840 >ON S,E,C 1850 >ON S,E,D 1860 >ON S,E,I 1870 >ON S,T,P 1880 >ON T,A,X 1890 >ON T,A,Y 1900 >ON T,C,D 1910 >ON T,C,S 1920 >ON T,D,C 1930 >ON T,S,C 1940 >ON T,S,X 1950 >ON T,X,A 1960 >ON T,X,S 1970 >ON T,X,Y 1980 >ON T,Y,A 1990 >ON T,Y,X 2000 >ON W,A,I 2010 >ON W,D,M 2020 >ON X,B,A 2030 >ON X,C,E 2040 *-------------------------------- 2050 OPNAMES.B 2060 >ON A,D,C 2070 >ON A,N,D 2080 >ON A,S,L 2090 >ON B,C,C 2100 >ON B,C,S 2110 >ON B,E,Q 2120 >ON B,I,T 2130 >ON B,M,I 2140 >ON B,N,E 2150 >ON B,P,L 2160 >ON B,R,A 2170 >ON B,R,L 2180 >ON B,V,C 2190 >ON B,V,S 2200 >ON C,M,P 2210 >ON C,P,X 2220 >ON C,P,Y 2230 >ON D,E,C 2240 >ON E,O,R 2250 >ON I,N,C 2260 >ON J,M,L 2270 >ON J,M,P 2280 >ON J,S,L 2290 >ON J,S,R 2300 >ON L,D,A 2310 >ON L,D,X 2320 >ON L,D,Y 2330 >ON L,S,R 2340 >ON M,V,N 2350 >ON M,V,P 2360 >ON O,R,A 2370 >ON P,E,A 2380 >ON P,E,I 2390 >ON P,E,R 2400 >ON R,E,P 2410 >ON R,O,L 2420 >ON R,O,R 2430 >ON S,B,C 2440 >ON S,E,P 2450 >ON S,T,A 2460 >ON S,T,X 2470 >ON S,T,Y 2480 >ON S,T,Z 2490 >ON T,R,B 2500 >ON T,S,B 2510 *-------------------------------- 2520 OPINDEX 2530 *---0X--------------------------- 2540 >OXA BRK 2550 >OXB ORA 2560 >OXA COP 2570 >OXB ORA 2580 >OXB TSB 2590 >OXB ORA 2600 >OXB ASL 2610 >OXB ORA 2620 >OXA PHP 2630 >OXB ORA 2640 >OXA ASLA 2650 >OXA PHD 2660 >OXB TSB 2670 >OXB ORA 2680 >OXB ASL 2690 >OXB ORA 2700 *---1X--------------------------- 2710 >OXB BPL 2720 >OXB ORA 2730 >OXB ORA 2740 >OXB ORA 2750 >OXB TRB 2760 >OXB ORA 2770 >OXB ASL 2780 >OXB ORA 2790 >OXA CLC 2800 >OXB ORA 2810 >OXA INCA 2820 >OXA TCS 2830 >OXB TRB 2840 >OXB ORA 2850 >OXB ASL 2860 >OXB ORA 2870 *---2X--------------------------- 2880 >OXB JSR 2890 >OXB AND 2900 >OXB JSL 2910 >OXB AND 2920 >OXB BIT 2930 >OXB AND 2940 >OXB ROL 2950 >OXB AND 2960 >OXA PLP 2970 >OXB AND 2980 >OXA ROLA 2990 >OXA PLD 3000 >OXB BIT 3010 >OXB AND 3020 >OXB ROL 3030 >OXB AND 3040 *---3X--------------------------- 3050 >OXB BMI 3060 >OXB AND 3070 >OXB AND 3080 >OXB AND 3090 >OXB BIT 3100 >OXB AND 3110 >OXB ROL 3120 >OXB AND 3130 >OXA SEC 3140 >OXB AND 3150 >OXA DECA 3160 >OXA TSC 3170 >OXB BIT 3180 >OXB AND 3190 >OXB ROL 3200 >OXB AND 3210 *---4X--------------------------- 3220 >OXA RTI 3230 >OXB EOR 3240 >OXA WDM 3250 >OXB EOR 3260 >OXB MVP 3270 >OXB EOR 3280 >OXB LSR 3290 >OXB EOR 3300 >OXA PHA 3310 >OXB EOR 3320 >OXA LSRA 3330 >OXA PHK 3340 >OXB JMP 3350 >OXB EOR 3360 >OXB LSR 3370 >OXB EOR 3380 *---5X--------------------------- 3390 >OXB BVC 3400 >OXB EOR 3410 >OXB EOR 3420 >OXB EOR 3430 >OXB MVN 3440 >OXB EOR 3450 >OXB LSR 3460 >OXB EOR 3470 >OXA CLI 3480 >OXB EOR 3490 >OXA PHY 3500 >OXA TCD 3510 >OXB JMP 3520 >OXB EOR 3530 >OXB LSR 3540 >OXB EOR 3550 *---6X--------------------------- 3560 >OXA RTS 3570 >OXB ADC 3580 >OXB PER 3590 >OXB ADC 3600 >OXB STZ 3610 >OXB ADC 3620 >OXB ROR 3630 >OXB ADC 3640 >OXA PLA 3650 >OXB ADC 3660 >OXA RORA 3670 >OXA RTL 3680 >OXB JMP 3690 >OXB ADC 3700 >OXB ROR 3710 >OXB ADC 3720 *---7X--------------------------- 3730 >OXB BVS 3740 >OXB ADC 3750 >OXB ADC 3760 >OXB ADC 3770 >OXB STZ 3780 >OXB ADC 3790 >OXB ROR 3800 >OXB ADC 3810 >OXA SEI 3820 >OXB ADC 3830 >OXA PLY 3840 >OXA TDC 3850 >OXB JMP 3860 >OXB ADC 3870 >OXB ROR 3880 >OXB ADC 3890 *---8X--------------------------- 3900 >OXB BRA 3910 >OXB STA 3920 >OXB BRL 3930 >OXB STA 3940 >OXB STY 3950 >OXB STA 3960 >OXB STX 3970 >OXB STA 3976 *>>>CHANGED FROM "TAY" 3977 .LIST ON 3980 >OXA DEY 3987 .LIST OFF 3990 >OXB BIT 4000 >OXA TXA 4010 >OXA PHB 4020 >OXB STY 4030 >OXB STA 4040 >OXB STX 4050 >OXB STA 4060 *---9X--------------------------- 4070 >OXB BCC 4080 >OXB STA 4090 >OXB STA 4100 >OXB STA 4110 >OXB STY 4120 >OXB STA 4130 >OXB STX 4140 >OXB STA 4150 >OXA TYA 4160 >OXB STA 4170 >OXA TXS 4180 >OXA TXY 4190 >OXB STZ 4200 >OXB STA 4210 >OXB STZ 4220 >OXB STA 4230 *---AX--------------------------- 4240 >OXB LDY 4250 >OXB LDA 4260 >OXB LDX 4270 >OXB LDA 4280 >OXB LDY 4290 >OXB LDA 4300 >OXB LDX 4310 >OXB LDA 4320 >OXA TAY 4330 >OXB LDA 4340 >OXA TAX 4350 >OXA PLB 4360 >OXB LDY 4370 >OXB LDA 4380 >OXB LDX 4390 >OXB LDA 4400 *---BX--------------------------- 4410 >OXB BCS 4420 >OXB LDA 4430 >OXB LDA 4440 >OXB LDA 4450 >OXB LDY 4460 >OXB LDA 4470 >OXB LDX 4480 >OXB LDA 4490 >OXA CLV 4500 >OXB LDA 4510 >OXA TSX 4520 >OXA TYX 4530 >OXB LDY 4540 >OXB LDA 4550 >OXB LDX 4560 >OXB LDA 4570 *---CX--------------------------- 4580 >OXB CPY 4590 >OXB CMP 4600 >OXB REP 4610 >OXB CMP 4620 >OXB CPY 4630 >OXB CMP 4640 >OXB DEC 4650 >OXB CMP 4660 >OXA INY 4670 >OXB CMP 4680 >OXA DEX 4690 >OXA WAI 4700 >OXB CPY 4710 >OXB CMP 4720 >OXB DEC 4730 >OXB CMP 4740 *---DX--------------------------- 4750 >OXB BNE 4760 >OXB CMP 4770 >OXB CMP 4780 >OXB CMP 4790 >OXB PEI 4800 >OXB CMP 4810 >OXB DEC 4820 >OXB CMP 4830 >OXA CLD 4840 >OXB CMP 4850 >OXA PHX 4860 >OXA STP 4870 >OXB JML 4880 >OXB CMP 4890 >OXB DEC 4900 >OXB CMP 4910 *---EX--------------------------- 4920 >OXB CPX 4930 >OXB SBC 4940 >OXB SEP 4950 >OXB SBC 4960 >OXB CPX 4970 >OXB SBC 4980 >OXB INC 4990 >OXB SBC 5000 >OXA INX 5010 >OXB SBC 5020 >OXA NOP 5030 >OXA XBA 5040 >OXB CPX 5050 >OXB SBC 5060 >OXB INC 5070 >OXB SBC 5080 *---FX--------------------------- 5090 >OXB BEQ 5100 >OXB SBC 5110 >OXB SBC 5120 >OXB SBC 5130 >OXB PEA 5140 >OXB SBC 5150 >OXB INC 5160 >OXB SBC 5170 >OXA SED 5180 >OXB SBC 5190 >OXA PLX 5200 >OXA XCE 5210 >OXB JSR 5220 >OXB SBC 5230 >OXB INC 5240 >OXB SBC 5250 *-------------------------------- 5260 OPFORMAT 5270 F.0 .HS 00.14.00.1C.02.02.02.20.00.00.00.00.04.04.04.06 5280 F.1 .HS 26.16.12.1E.02.08.08.22.00.10.00.00.04.0A.0A.0C 5290 F.2 .HS 04.14.06.1C.02.02.02.20.00.00.00.00.04.04.04.06 5300 F.3 .HS 26.16.12.1E.08.08.08.22.00.10.00.00.0A.0A.0A.0C 5310 F.4 .HS 00.14.00.1C.24.02.02.20.00.00.00.00.04.04.04.06 5320 F.5 .HS 26.16.12.1E.24.08.08.22.00.10.00.00.06.0A.0A.0C 5330 F.6 .HS 00.14.28.1C.02.02.02.20.00.00.00.00.18.04.04.06 5340 F.7 .HS 26.16.12.1E.08.08.08.22.00.10.00.00.1A.0A.0A.0C 5350 F.8 .HS 26.14.28.1C.02.02.02.20.00.00.00.00.04.04.04.06 5360 F.9 .HS 26.16.12.1E.08.08.0E.22.00.10.00.00.04.0A.0A.0C 5370 F.A .HS 00.14.00.1C.02.02.02.20.00.00.00.00.04.04.04.06 5380 F.B .HS 26.16.12.1E.08.08.0E.22.00.10.00.00.0A.0A.10.0C 5390 F.C .HS 00.14.00.1C.02.02.02.20.00.00.00.00.04.04.04.06 5400 F.D .HS 26.16.12.1E.02.08.08.22.00.10.00.00.18.0A.0A.0C 5410 F.E .HS 00.14.00.1C.02.02.02.20.00.00.00.00.04.04.04.06 5420 F.F .HS 26.16.12.1E.08.08.08.22.00.10.00.00.1A.0A.0A.0C 5430 *-------------------------------- 5440 FMTBL 5450 *-----# > ( $ , X S ) , Y $ - - - LL 5460 .DA %1.0.0.1.0.0.0.0.0.0.0.0.0.0.01 -- IMMEDIATE 00 5470 .DA %0.0.0.1.0.0.0.0.0.0.0.0.0.0.01 -- DIRECT 02 5480 .DA %0.0.0.1.0.0.0.0.0.0.0.0.0.0.10 -- ABS 04 5490 .DA %0.0.0.1.0.0.0.0.0.0.0.0.0.0.11 -- LONG 06 5500 *-----# > ( $ , X S ) , Y $ - - - LL 5510 .DA %0.0.0.1.1.1.0.0.0.0.0.0.0.0.01 -- DIRECT,X 08 5520 .DA %0.0.0.1.1.1.0.0.0.0.0.0.0.0.10 -- ABS,X 0A 5530 .DA %0.0.0.1.1.1.0.0.0.0.0.0.0.0.11 -- LONG,X 0C 5540 *-----# > ( $ , X S ) , Y $ - - - LL 5550 .DA %0.0.0.1.1.0.0.0.0.1.0.0.0.0.01 -- DIRECT,Y 0E 5560 .DA %0.0.0.1.1.0.0.0.0.1.0.0.0.0.10 -- ABS,Y 10 5570 *-----# > ( $ , X S ) , Y $ - - - LL 5580 .DA %0.0.1.1.0.0.0.1.0.0.0.0.0.0.01 -- IND 12 5590 .DA %0.0.1.1.1.1.0.1.0.0.0.0.0.0.01 -- INDX 14 5600 .DA %0.0.1.1.0.0.0.1.1.1.0.0.0.0.01 -- INDY 16 5610 *-----# > ( $ , X S ) , Y $ - - - LL 5620 .DA %0.0.1.1.0.0.0.1.0.0.0.0.0.0.10 -- INDABS 18 5630 .DA %0.0.1.1.1.1.0.1.0.0.0.0.0.0.10 -- INDABSX 1A 5640 *-----# > ( $ , X S ) , Y $ - - - LL 5650 .DA %0.0.0.1.1.0.1.0.0.0.0.0.0.0.01 -- STK 1C 5660 .DA %0.0.1.1.1.0.1.1.1.1.0.0.0.0.01 -- STKY 1E 5670 *-----# > ( $ , X S ) , Y $ - - - LL 5680 .DA %0.1.1.1.0.0.0.1.0.0.0.0.0.0.01 -- INDLONG 20 5690 .DA %0.1.1.1.0.0.0.1.1.1.0.0.0.0.01 -- INDLONGY 22 5700 .DA %0.0.0.1.0.0.0.0.1.0.1.0.0.0.10 -- MVN & MVP 24 5710 .DA %0.0.0.0.0.0.0.0.0.0.1.0.0.0.01 -- RELATIVE 26 5720 .DA %0.0.0.0.0.0.0.0.0.0.1.0.0.0.10 -- LONG RELA. 28 5730 *-------------------------------- 5740 FMTSTR .AS -/$Y,)SX,$(>#/ 5750 *-------------------------------- 5760 INSDS1 JSR CROUT 5770 LDA PCH 5780 JSR PRBYTE 5790 LDA PCL 5800 JSR PRBYTE 5810 LDA #"-" 5820 JSR COUT 5830 LDA #" " 5840 JSR COUT 5850 LDY #0 5860 LDA (PCL),Y GET OPCODE 5863 .LIST ON 5864 *>>>INSERT LINE HERE 5865 JSR TEST.OP.CODES <<<>>> 5866 .LIF 5870 INSDS2 TAY SAVE IN Y-REG 5880 LDA OPINDEX,Y 5890 ASL 5900 TAX 5910 BCC .1 ...NOT SINGLE BYTE OPCODE 5920 LDA OPNAMES.A,X 5930 STA RMNEM 5940 LDA OPNAMES.A+1,X 5950 STA LMNEM 5960 LDA #0 5970 STA LENGTH 5980 RTS 5990 *-------------------------------- 6000 .1 LDA OPNAMES.B,X 6010 STA RMNEM 6020 LDA OPNAMES.B+1,X 6030 STA LMNEM 6040 LDX OPFORMAT,Y 6050 LDA FMTBL+1,X 6060 STA FORMATH 6070 LDA FMTBL,X 6080 STA FORMATL 6090 AND #3 6100 STA LENGTH 6110 TXA CHECK IF IMMEDIATE 6120 BNE .2 ...NO 6130 BIT IMM.SIZE CHECK IF 16-BIT MODE 6140 BPL .2 ...NO 6150 INC LENGTH ...YES 6160 .2 RTS 6170 *-------------------------------- 6180 INSTDSP 6190 JSR INSDS1 6200 LDY #0 PRINT BYTES OF OPCODE & OPERAND 6210 .1 LDA (PCL),Y 6220 JSR PRBYTE 6230 LDX #1 PRINT 1 BLANK 6240 .2 JSR PRBL2 6250 CPY LENGTH 6260 INY 6270 BCC .1 6280 LDX #3 6290 CPY #4 6300 BCC .2 6310 *---PRINT MNEMONIC--------------- 6320 LDY #3 THREE LETTERS 6330 .3 LDA #6 SHIFT OUT ONE LETTER, TOP BITS 11 6340 .4 ASL RMNEM 6350 ROL LMNEM 6360 ROL 6370 BPL .4 ...NOT ENUF BITS YET 6380 JSR COUT PRINT THE LETTER 6390 DEY 6400 BNE .3 ...MORE LETTERS 6410 LDY LENGTH 6420 BEQ .8 ...SINGLE BYTE OPCODE 6430 LDA FORMATL 6440 AND #$20 SEE IF SPECIAL 6450 BNE .9 ...YES, MOVES OR RELATIVES 6460 *---PRINT NORMAL OPERANDS-------- 6470 LDA #" " 6480 JSR COUT 6490 LDX #10 11 FORMAT BITS 6500 .5 ASL FORMATL 6510 ROL FORMATH 6520 BCC .7 6530 LDA FMTSTR,X 6540 JSR COUT 6550 CMP #"#" 6560 BNE .55 6570 BIT IMM.SIZE 6580 BPL .7 6590 JSR COUT 6600 .55 CMP #"$" 6610 BNE .7 6620 .6 LDA (PCL),Y 6630 JSR PRBYTE 6640 DEY 6650 BNE .6 6660 .7 DEX 6670 BPL .5 6680 .8 RTS 6690 *---SPECIAL CASES---------------- 6700 .9 LDA #" " 6710 JSR COUT 6720 LDA #"$" 6730 JSR COUT 6740 LDA FORMATL 6750 BMI .11 MVN & MVP 6755 .LIST ON 6760 *---8- OR 16-BIT RELATIVE-------- 6770 LDA (PCL),Y 8=OFFSET, 16=OFFSETHI 6780 DEY TEST LENGTH 6790 STY FORMATH =0 IF 8-BIT 6800 BEQ .10 ...8-BIT 6810 STA FORMATH ...16-BIT 6820 LDA (PCL),Y LOW BYTE OF 16-BIT OFFSET 6830 .10 STA FORMATL 6840 JSR PCADJ 6850 CLC 6860 ADC FORMATL 6870 TAX 6880 TYA 6890 ADC FORMATH 6900 JMP PRNTAX 6905 .LIST OFF 6960 *---MVN & MVP-------------------- 6970 .11 LDA (PCL),Y 6980 JSR PRBYTE 6990 LDA #"," 7000 JSR COUT 7010 LDA #"$" 7020 JSR COUT 7030 DEY 7040 LDA (PCL),Y 7050 JMP PRBYTE 7055 .LIST ON 7060 *-------------------------------- 7070 TEST.OP.CODES 7080 PHA SAVE OPCODE 7090 LSR IMM.SIZE ASSUME 8-BIT IMMEDIATE 7100 LDX STATUS.PNTR 7110 CMP #$18 CLC? 7120 BEQ CLC.OP 7130 CMP #$38 SEC? 7140 BEQ SEC.OP 7150 INY 7160 CMP #$C2 REP? 7170 BEQ REP.OP 7180 CMP #$E2 SEP? 7190 BEQ SEP.OP 7200 DEY 7210 CMP #$08 PHP? 7220 BEQ PHP.OP 7230 CMP #$28 PLP? 7240 BEQ PLP.OP 7250 CMP #$FB XCE? 7260 BEQ XCE.OP 7270 *-------------------------------- 7280 AND #$1F ORA, AND, EOR, ADC, BIT, LDA, CMP, SBC? 7290 CMP #$09 7300 PHP SAVE ANSWER 7310 LDA #$20 ASSUME M-BIT 7320 PLP GET PREVIOUS ANSWER 7330 BEQ .1 IT IS M-BIT 7340 LSR (LDA #$10) USE X-BIT INSTEAD 7350 .1 AND STATUS.STACK,X 7360 BNE .2 ...USE 8-BIT IMMEDIATE 7370 LDA E.BIT 7380 LSR 7390 BCS .2 E=1, USE 8-BIT IMMEDIATE 7400 LDA #$FF ...USE 16-BIT IMMEDIATE 7410 STA IMM.SIZE 7420 .2 PLA GET OPCODE AGAIN 7430 RTS 7440 *-------------------------------- 7450 CLC.OP LDA STATUS.STACK,X 7460 AND #$FE 7470 UPDATE.STATUS 7480 STA STATUS.STACK,X 7490 PLA 7500 RTS 7510 *-------------------------------- 7520 SEC.OP LDA STATUS.STACK,X 7530 ORA #$01 7540 BNE UPDATE.STATUS ...ALWAYS 7550 *-------------------------------- 7560 REP.OP LDA (PCL),Y LOOK AT OPERAND 7570 EOR #$FF 7580 AND STATUS.STACK,X 7590 JMP UPDATE.STATUS 7600 *-------------------------------- 7610 SEP.OP LDA (PCL),Y 7620 ORA STATUS.STACK,X 7630 JMP UPDATE.STATUS 7640 *-------------------------------- 7650 PHP.OP LDA STATUS.STACK,X 7660 INX 7670 CPX #8 7680 BCC PHP.PLP 7690 LDX #0 7700 PHP.PLP 7710 STX STATUS.PNTR 7720 JMP UPDATE.STATUS 7730 *-------------------------------- 7740 PLP.OP DEX 7750 BPL PHP.PLP 7760 LDX #7 7770 BEQ PHP.PLP 7780 *-------------------------------- 7790 XCE.OP LSR E.BIT GET E-BIT INTO CARRY 7800 PHP SAVE IT 7810 LDA STATUS.STACK,X 7820 STA E.BIT NEW E-BIT 7830 LSR C-BIT INTO CARRY 7840 BCC .1 ...NEW E-BIT = 0 7850 ORA #$18 ...NEW E-BIT=1, SO SET M=X=1 7860 .1 PLP GET NEW C-BIT (OLD E-BIT) 7870 ROL PUT IT INTO STATUS BYTE 7880 JMP UPDATE.STATUS 7890 *-------------------------------- 7900 TT LDY #0 7910 LDA #$C0 7920 STA PCL 7930 LDA #2 $2C0...$3C3 7940 STA PCH 7950 .1 TYA 7960 STA $2C0,Y 7970 INY 7980 BNE .1 7990 STY $3C0 8000 INY 8010 STY $3C1 8020 INY 8030 STY $3C2 8040 .2 JSR INSTDSP 8050 LDY #0 8060 LDA (PCL),Y 8070 CMP #$FF 8080 BEQ .3 8090 .4 LDA $C000 8100 BPL .4 8110 STA $C010 8120 INC PCL 8130 BNE .2 8140 INC PCH 8150 BNE .2 ...ALWAYS 8160 .3 RTS 8170 *-------------------------------- 8180 .LIF |
| Fastest 6502 Multiplication Yet | Charles Putney Shankill, Dublin, Ireland |
Here is an 8x8 multiply routine that will blow your socks off! The maximum time, including both a calling JSR and a returning RTS, is only 66 cycles! The minimum is 60 cycles, and most factors will multiply in 63 cycles. Recall that the fastest time in Bob S-C's January 1986 AAL article for a 6502 was 132 cycles. My new one is twice as fast!
As with most fast routines, there is a trade off in memory space. My program uses 1024 bytes of lookup tables. This isn't so bad if you really need or want a 2:1 speed advantage.
My routine is based on the fact that:
4 * X * Y = (X+Y)^2 - (X-Y)^2
I got this idea from an article in EDN Magazine by Arch D. Robison (October 13, 1983, pages 263-4). His routine used the fact that:
2 * X * Y = X^2 + Y^2 - (X-Y)^2
Robison's method requires three dips into the lookup tables. Formulated to the same method for passing parameters, his method takes either 74 or 77 cycles. Here is my rendition of his method:
1000 *SAVE ROBISONS.8X8 1010 *-------------------------------- 1020 * MODIFIED FROM ORIGINAL PROGRAM 1030 * BY ARCH D. ROBISON, BURROUGHS CORP. 1040 * EDN, OCTOBER 13, 1983. 1050 *-------------------------------- 1060 * ENTER WITH (A)=MULTIPLIER # 1 1070 * (X)=MULTIPLIER #2 1080 * EXIT WITH (A)=PRODUCT HI BYTE 1090 * (X)=PRODUCT LO BYTE 1100 *-------------------------------- 1110 PROD .EQ $06 PRODUCT TEMP OF M1*M2 (LOW BYTE) 1120 M2 .EQ $07 TEMP FOR M2 SAVE 1130 *-------------------------------- 1140 MULT8 TAY SAVE M1 IN Y 1150 STX M2 SAVE M2 1160 AND M2 CHECK IF BOTH FACTORS ARE ODD 1170 LSR SET CARRY <--> BOTH ODD 1180 LDA SQL,X ADD (X*X)/2 AND (Y*Y)/2 1190 ADC SQL,Y 1200 STA PROD SAVE LO BYTE OF PRODUCT 1210 LDA SQH,X 1220 ADC SQH,Y 1230 TAX SAVE HI BYTE OF PRODUCT 1240 TYA GET M1 BACK 1250 SEC 1260 SBC M2 FIND M1 - M2 1270 BCS .1 M1 >= M2, CONTINUE 1280 SBC #0 M1 < M2, FORM 2'S COMPLEMENT 1290 EOR #$FF 1300 .1 TAY USE ABS(M1-M2) AS INDEX 1310 LDA PROD TO FIND SQUARE/2 IN TABLE 1320 SBC SQL,Y NOW SUBTRACT (X-Y)*(X-Y) 1330 STA PROD SAVE LO BYTE OF RESULT 1340 TXA HI BYTE FROM PREVIOUS SUM 1350 SBC SQH,Y 1360 LDX PROD LO BYTE OF FINAL PRODUCT 1370 RTS 1380 *-------------------------------- 1390 .OR $900 PAGE BOUNDARY TO SAVE MAX 6 CYCLES 1400 *-------------------------------- 1410 SQL 1420 .DA #0,#0,#2,#4,#8,#12,#18,#24 1430 .DA #32,#40,#50,#60,#72,#84,#98,#112 1440 .DA #128,#144,#162,#180,#200,#220,#242,#264 1450 .DA #288,#312,#338,#364,#392,#420,#450,#480 1460 .DA #512,#544,#578,#612,#648,#684,#722,#760 1470 .DA #800,#840,#882,#924,#968,#1012,#1058,#1104 1480 .DA #1152,#1200,#1250,#1300,#1352,#1404,#1458,#1512 1490 .DA #1568,#1624,#1682,#1740,#1800,#1860,#1922,#1984 1500 .DA #2048,#2112,#2178,#2244,#2312,#2380,#2450,#2520 1510 .DA #2592,#2664,#2738,#2812,#2888,#2964,#3042,#3120 1520 .DA #3200,#3280,#3362,#3444,#3528,#3612,#3698,#3784 1530 .DA #3872,#3960,#4050,#4140,#4232,#4324,#4418,#4512 1540 .DA #4608,#4704,#4802,#4900,#5000,#5100,#5202,#5304 1550 .DA #5408,#5512,#5618,#5724,#5832,#5940,#6050,#6160 1560 .DA #6272,#6384,#6498,#6612,#6728,#6844,#6962,#7080 1570 .DA #7200,#7320,#7442,#7564,#7688,#7812,#7938,#8064 1580 .DA #8192,#8320,#8450,#8580,#8712,#8844,#8978,#9112 1590 .DA #9248,#9384,#9522,#9660,#9800,#9940,#10082,#10224 1600 .DA #10368,#10512,#10658,#10804,#10952,#11100,#11250,#11400 1610 .DA #11552,#11704,#11858,#12012,#12168,#12324,#12482,#12640 1620 .DA #12800,#12960,#13122,#13284,#13448,#13612,#13778,#13944 1630 .DA #14112,#14280,#14450,#14620,#14792,#14964,#15138,#15312 1640 .DA #15488,#15664,#15842,#16020,#16200,#16380,#16562,#16744 1650 .DA #16928,#17112,#17298,#17484,#17672,#17860,#18050,#18240 1660 .DA #18432,#18624,#18818,#19012,#19208,#19404,#19602,#19800 1670 .DA #20000,#20200,#20402,#20604,#20808,#21012,#21218,#21424 1680 .DA #21632,#21840,#22050,#22260,#22472,#22684,#22898,#23112 1690 .DA #23328,#23544,#23762,#23980,#24200,#24420,#24642,#24864 1700 .DA #25088,#25312,#25538,#25764,#25992,#26220,#26450,#26680 1710 .DA #26912,#27144,#27378,#27612,#27848,#28084,#28322,#28560 1720 .DA #28800,#29040,#29282,#29524,#29768,#30012,#30258,#30504 1730 .DA #30752,#31000,#31250,#31500,#31752,#32004,#32258,#32512 1740 SQH 1750 .DA /0,/0,/2,/4,/8,/12,/18,/24 1760 .DA /32,/40,/50,/60,/72,/84,/98,/112 1770 .DA /128,/144,/162,/180,/200,/220,/242,/264 1780 .DA /288,/312,/338,/364,/392,/420,/450,/480 1790 .DA /512,/544,/578,/612,/648,/684,/722,/760 1800 .DA /800,/840,/882,/924,/968,/1012,/1058,/1104 1810 .DA /1152,/1200,/1250,/1300,/1352,/1404,/1458,/1512 1820 .DA /1568,/1624,/1682,/1740,/1800,/1860,/1922,/1984 1830 .DA /2048,/2112,/2178,/2244,/2312,/2380,/2450,/2520 1840 .DA /2592,/2664,/2738,/2812,/2888,/2964,/3042,/3120 1850 .DA /3200,/3280,/3362,/3444,/3528,/3612,/3698,/3784 1860 .DA /3872,/3960,/4050,/4140,/4232,/4324,/4418,/4512 1870 .DA /4608,/4704,/4802,/4900,/5000,/5100,/5202,/5304 1880 .DA /5408,/5512,/5618,/5724,/5832,/5940,/6050,/6160 1890 .DA /6272,/6384,/6498,/6612,/6728,/6844,/6962,/7080 1900 .DA /7200,/7320,/7442,/7564,/7688,/7812,/7938,/8064 1910 .DA /8192,/8320,/8450,/8580,/8712,/8844,/8978,/9112 1920 .DA /9248,/9384,/9522,/9660,/9800,/9940,/10082,/10224 1930 .DA /10368,/10512,/10658,/10804,/10952,/11100,/11250,/11400 1940 .DA /11552,/11704,/11858,/12012,/12168,/12324,/12482,/12640 1950 .DA /12800,/12960,/13122,/13284,/13448,/13612,/13778,/13944 1960 .DA /14112,/14280,/14450,/14620,/14792,/14964,/15138,/15312 1970 .DA /15488,/15664,/15842,/16020,/16200,/16380,/16562,/16744 1980 .DA /16928,/17112,/17298,/17484,/17672,/17860,/18050,/18240 1990 .DA /18432,/18624,/18818,/19012,/19208,/19404,/19602,/19800 2000 .DA /20000,/20200,/20402,/20604,/20808,/21012,/21218,/21424 2010 .DA /21632,/21840,/22050,/22260,/22472,/22684,/22898,/23112 2020 .DA /23328,/23544,/23762,/23980,/24200,/24420,/24642,/24864 2030 .DA /25088,/25312,/25538,/25764,/25992,/26220,/26450,/26680 2040 .DA /26912,/27144,/27378,/27612,/27848,/28084,/28322,/28560 2050 .DA /28800,/29040,/29282,/29524,/29768,/30012,/30258,/30504 2060 .DA /30752,/31000,/31250,/31500,/31752,/32004,/32258,/32512 |
The entries in the two tables (SQL and SQH) are the squares of the numbers from 0 to 255, divided by two. The low bytes are in the SQL table, and the high bytes are in SQH. Dividing by two throws away an important bit for odd factors, but lines 1160-1170 compensate for the loss.
I looked for a way to add fewer table entries together and came upon the sum^2 - diff^2. Since the sum can be as large as 255+255=510, I need twice as much table space. Lest you despair of typing in such a large table, let me offer an Applesoft program which will write a text file of the source code for the table:
100 D$ = CHR$ (4)
110 PRINT D$"OPEN TEMPFILE"
120 PRINT D$"WRITE TEMPFILE"
1000 REM CREATE SQUARE/4 TABLE
1010 PRINT "1000 SQL":A$ = "#":L = 1010
1020 FOR I = 0 TO 510 STEP 8: GOSUB 2000
1030 NEXT I
1100 PRINT "2000 SQH":A$ = "/":L = 2010
1110 FOR I = 0 TO 510 STEP 8: GOSUB 2000
1120 NEXT I
1130 PRINT D$"CLOSE": END
2000 REM GENERATE 8 ITEMS
2010 N = INT (I * I / 4): PRINT L" .DA "A$;N;
2020 FOR J = I + 1 TO I + 7
2030 N = INT (J * J / 4): PRINT ","A$;N;
2040 NEXT J:L = L + 10
2050 PRINT : RETURN
My tables contain the squares divided by four. I can hear you saying, "Wait a minute! You can't just divide by four and truncate!" Well, even squares are all multiples of four; odd squares are all multiples of four with a remainder = 1. The sum of two numbers and the difference of the same numbers are either both even or both odd. Therefore, we never lose anything by throwing away our truncated 1.
The number of cycles my MULT8 takes depends on the values of the two factors. You call MULT8 with one factor in the A-register and the other in the X-register. If (A) is less than (X), it takes an extra 3 cycles to perform a complement operation. If the sum of the factors is greater than 255, add another three cycles. To summarize,
A>=X | A<X
-----------------------
sum<256 | 60 | 63
sum>255 | 63 | 66
-----------------------
Just for fun, I also wrote a program to generate the square/4 tables. This takes less time than loading the tables from disk, so it could mean faster booting for some hi-resolution game program that needs super-fast multiplications. It is in lines 1560-2100 below.
The origin I used in my program is meant just to allow me to test it. I wrote an Applesoft program to call TEST at $6000 (CALL 24576). The program POKEd two factors at $FA and $FB, called TEST, and then checked the result at the same two locations. If you want to use MULT8, you should just assemble it along with the rest of your program, without any special origin. You should make sure that the tables start on an even page boundary, or it will cost you up to 8 cycles extra for indexing across a page boundary.
1000 *SAVE PUTNEYS.8X8 1010 *-------------------------------- 1020 * ULTRA-FAST 8 X 8 MULTIPLY 1030 *-------------------------------- 1040 * ENTER WITH (A)=MULTIPLIER # 1 1050 * (X)=MULTIPLIER #2 1060 * EXIT WITH (A)=PRODUCT HI BYTE 1070 * (X)=PRODUCT LO BYTE 1080 *-------------------------------- 1090 * TIMING DATA 1100 * MINIMUM TIME = 54 CYCLES 1110 * MAXIMUM TIME = 60 CYCLES 1120 * AVERAGE TIME = 57 CYCLES 1130 *-------------------------------- 1140 PROD .EQ $06 PRODUCT TEMP OF M1*M2 (LOW BYTE) 1150 M2 .EQ $07 TEMP FOR M2 SAVE 1160 *-------------------------------- 1170 .OR $6000 SAFE PLACE 1180 *-------------------------------- 1190 * TEST FOR APPLESOFT DRIVER 1200 *-------------------------------- 1210 TEST LDA $FA LOAD ACC AND X SO BASIC CAN TEST 1220 LDX $FB 1230 JSR MULT8 1240 STX $FA NOW BASIC CAN CHECK ACC AND X 1250 STA $FB 1260 RTS 1270 *-------------------------------- 1280 MULT8 TAY SAVE M1 IN Y 1290 STX M2 SAVE M2 1300 SEC SET CARRY FOR SUBTRACT 1310 SBC M2 FIND DIFFERENCE 1320 BCS .1 WAS M1 > M2 ? 1330 EOR #$FF INVERT IT 1340 ADC #$01 AND ADD 1 1350 .1 TAX USE ABS(M1-M2) AS INDEX 1360 CLC 1370 TYA GET M1 BACK 1380 ADC M2 FIND M1 + M2 1390 TAY USE M1+M2 AS INDEX 1400 BCC .2 M1+M2 < 255 ? 1410 LDA SQL+256,Y FIND SUM SQUARED LOW IF > 255 1420 SBC SQL,X SUBTRACT DIFF SQUARED 1430 STA PROD SAVE IN PRODUCT 1440 LDA SQH+256,Y HI BYTE 1450 SBC SQH,X 1460 LDX PROD GET PROD LOW IN X 1470 RTS DONE 1480 .2 SEC SET CARRY FOR SUBTRACT 1490 LDA SQL,Y FIND SUM OF SQUARES LOW IF < 255 1500 SBC SQL,X SUBTRACT DIFF SQUARED 1510 STA PROD SAVE IN PRODUCT 1520 LDA SQH,Y HI BYTE 1530 SBC SQH,X 1540 LDX PROD GET PROD LOW IN X 1550 RTS 1560 *-------------------------------- 1570 * PROGRAM TO CREATE A TABLE OF SQUARES/4 1580 *-------------------------------- 1590 LOTP .EQ 0,1 1600 HITP .EQ 2,3 1610 *-------------------------------- 1620 SQUARE LDY #0 1630 STY LOTP 1640 STY HITP 1650 STY SQ 1660 STY SQ+1 1670 STY SQ+2 1680 STY DELTA+1 1690 STY DELTA+2 1700 STY $6800 1710 STY $6A00 1720 INY 1730 LDA #$40 1740 STA DELTA 1750 LDA /$6800 1760 STA LOTP+1 1770 LDA /$6A00 1780 STA HITP+1 1790 LDX #1 1800 *-------------------------------- 1810 .1 CLC 1820 LDA DELTA 1830 ADC SQ 1840 STA SQ 1850 LDA DELTA+1 1860 ADC SQ+1 1870 STA SQ+1 1880 STA (LOTP),Y 1890 LDA DELTA+2 1900 ADC SQ+2 1910 STA SQ+2 1920 STA (HITP),Y 1930 *-------------------------------- 1940 LDA DELTA 1950 ADC #$80 1960 STA DELTA 1970 BCC .2 1980 INC DELTA+1 1990 BNE .2 2000 INC DELTA+2 2010 .2 INY 2020 BNE .1 2030 INC LOTP+1 2040 INC HITP+1 2050 DEX 2060 BPL .1 2070 RTS 2080 *-------------------------------- 2090 DELTA .BS 3 2100 SQ .BS 3 2110 *-------------------------------- 2120 * TABLE OF SQUARES/4 FROM 0 TO 511 2130 *-------------------------------- 2140 .BS *+$FF/$100*$100-* KEEP TABLES ALIGNED ON PAGE BOUNDARY 2150 *-------------------------------- 2160 SQL .DA #0,#0,#1,#2,#4,#6,#9,#12 2170 .DA #16,#20,#25,#30,#36,#42,#49,#56 2180 .DA #64,#72,#81,#90,#100,#110,#121,#132 2190 .DA #144,#156,#169,#182,#196,#210,#225,#240 2200 .LIF 2210 .DA #256,#272,#289,#306,#324,#342,#361,#380 2220 .DA #400,#420,#441,#462,#484,#506,#529,#552 2230 .DA #576,#600,#625,#650,#676,#702,#729,#756 2240 .DA #784,#812,#841,#870,#900,#930,#961,#992 2250 .DA #1024,#1056,#1089,#1122,#1156,#1190,#1225,#1260 2260 .DA #1296,#1332,#1369,#1406,#1444,#1482,#1521,#1560 2270 .DA #1600,#1640,#1681,#1722,#1764,#1806,#1849,#1892 2280 .DA #1936,#1980,#2025,#2070,#2116,#2162,#2209,#2256 2290 .DA #2304,#2352,#2401,#2450,#2500,#2550,#2601,#2652 2300 .DA #2704,#2756,#2809,#2862,#2916,#2970,#3025,#3080 2310 .DA #3136,#3192,#3249,#3306,#3364,#3422,#3481,#3540 2320 .DA #3600,#3660,#3721,#3782,#3844,#3906,#3969,#4032 2330 .DA #4096,#4160,#4225,#4290,#4356,#4422,#4489,#4556 2340 .DA #4624,#4692,#4761,#4830,#4900,#4970,#5041,#5112 2350 .DA #5184,#5256,#5329,#5402,#5476,#5550,#5625,#5700 2360 .DA #5776,#5852,#5929,#6006,#6084,#6162,#6241,#6320 2370 .DA #6400,#6480,#6561,#6642,#6724,#6806,#6889,#6972 2380 .DA #7056,#7140,#7225,#7310,#7396,#7482,#7569,#7656 2390 .DA #7744,#7832,#7921,#8010,#8100,#8190,#8281,#8372 2400 .DA #8464,#8556,#8649,#8742,#8836,#8930,#9025,#9120 2410 .DA #9216,#9312,#9409,#9506,#9604,#9702,#9801,#9900 2420 .DA #10000,#10100,#10201,#10302,#10404,#10506,#10609,#10712 2430 .DA #10816,#10920,#11025,#11130,#11236,#11342,#11449,#11556 2440 .DA #11664,#11772,#11881,#11990,#12100,#12210,#12321,#12432 2450 .DA #12544,#12656,#12769,#12882,#12996,#13110,#13225,#13340 2460 .DA #13456,#13572,#13689,#13806,#13924,#14042,#14161,#14280 2470 .DA #14400,#14520,#14641,#14762,#14884,#15006,#15129,#15252 2480 .DA #15376,#15500,#15625,#15750,#15876,#16002,#16129,#16256 2490 .DA #16384,#16512,#16641,#16770,#16900,#17030,#17161,#17292 2500 .DA #17424,#17556,#17689,#17822,#17956,#18090,#18225,#18360 2510 .DA #18496,#18632,#18769,#18906,#19044,#19182,#19321,#19460 2520 .DA #19600,#19740,#19881,#20022,#20164,#20306,#20449,#20592 2530 .DA #20736,#20880,#21025,#21170,#21316,#21462,#21609,#21756 2540 .DA #21904,#22052,#22201,#22350,#22500,#22650,#22801,#22952 2550 .DA #23104,#23256,#23409,#23562,#23716,#23870,#24025,#24180 2560 .DA #24336,#24492,#24649,#24806,#24964,#25122,#25281,#25440 2570 .DA #25600,#25760,#25921,#26082,#26244,#26406,#26569,#26732 2580 .DA #26896,#27060,#27225,#27390,#27556,#27722,#27889,#28056 2590 .DA #28224,#28392,#28561,#28730,#28900,#29070,#29241,#29412 2600 .DA #29584,#29756,#29929,#30102,#30276,#30450,#30625,#30800 2610 .DA #30976,#31152,#31329,#31506,#31684,#31862,#32041,#32220 2620 .DA #32400,#32580,#32761,#32942,#33124,#33306,#33489,#33672 2630 .DA #33856,#34040,#34225,#34410,#34596,#34782,#34969,#35156 2640 .DA #35344,#35532,#35721,#35910,#36100,#36290,#36481,#36672 2650 .DA #36864,#37056,#37249,#37442,#37636,#37830,#38025,#38220 2660 .DA #38416,#38612,#38809,#39006,#39204,#39402,#39601,#39800 2670 .DA #40000,#40200,#40401,#40602,#40804,#41006,#41209,#41412 2680 .DA #41616,#41820,#42025,#42230,#42436,#42642,#42849,#43056 2690 .DA #43264,#43472,#43681,#43890,#44100,#44310,#44521,#44732 2700 .DA #44944,#45156,#45369,#45582,#45796,#46010,#46225,#46440 2710 .DA #46656,#46872,#47089,#47306,#47524,#47742,#47961,#48180 2720 .DA #48400,#48620,#48841,#49062,#49284,#49506,#49729,#49952 2730 .DA #50176,#50400,#50625,#50850,#51076,#51302,#51529,#51756 2740 .DA #51984,#52212,#52441,#52670,#52900,#53130,#53361,#53592 2750 .DA #53824,#54056,#54289,#54522,#54756,#54990,#55225,#55460 2760 .DA #55696,#55932,#56169,#56406,#56644,#56882,#57121,#57360 2770 .DA #57600,#57840,#58081,#58322,#58564,#58806,#59049,#59292 2780 .DA #59536,#59780,#60025,#60270,#60516,#60762,#61009,#61256 2790 .DA #61504,#61752,#62001,#62250,#62500,#62750,#63001,#63252 2800 .DA #63504,#63756,#64009,#64262,#64516,#64770,#65025,#65280 2810 *-------------------------------- 2820 .LIST ON 2830 SQH .DA /0,/0,/1,/2,/4,/6,/9,/12 2840 .DA /16,/20,/25,/30,/36,/42,/49,/56 2850 .DA /64,/72,/81,/90,/100,/110,/121,/132 2860 .LIST OFF 2870 .DA /144,/156,/169,/182,/196,/210,/225,/240 2880 .DA /256,/272,/289,/306,/324,/342,/361,/380 2890 .DA /400,/420,/441,/462,/484,/506,/529,/552 2900 .DA /576,/600,/625,/650,/676,/702,/729,/756 2910 .DA /784,/812,/841,/870,/900,/930,/961,/992 2920 .DA /1024,/1056,/1089,/1122,/1156,/1190,/1225,/1260 2930 .DA /1296,/1332,/1369,/1406,/1444,/1482,/1521,/1560 2940 .DA /1600,/1640,/1681,/1722,/1764,/1806,/1849,/1892 2950 .DA /1936,/1980,/2025,/2070,/2116,/2162,/2209,/2256 2960 .DA /2304,/2352,/2401,/2450,/2500,/2550,/2601,/2652 2970 .DA /2704,/2756,/2809,/2862,/2916,/2970,/3025,/3080 2980 .DA /3136,/3192,/3249,/3306,/3364,/3422,/3481,/3540 2990 .DA /3600,/3660,/3721,/3782,/3844,/3906,/3969,/4032 3000 .DA /4096,/4160,/4225,/4290,/4356,/4422,/4489,/4556 3010 .DA /4624,/4692,/4761,/4830,/4900,/4970,/5041,/5112 3020 .DA /5184,/5256,/5329,/5402,/5476,/5550,/5625,/5700 3030 .DA /5776,/5852,/5929,/6006,/6084,/6162,/6241,/6320 3040 .DA /6400,/6480,/6561,/6642,/6724,/6806,/6889,/6972 3050 .DA /7056,/7140,/7225,/7310,/7396,/7482,/7569,/7656 3060 .DA /7744,/7832,/7921,/8010,/8100,/8190,/8281,/8372 3070 .DA /8464,/8556,/8649,/8742,/8836,/8930,/9025,/9120 3080 .DA /9216,/9312,/9409,/9506,/9604,/9702,/9801,/9900 3090 .DA /10000,/10100,/10201,/10302,/10404,/10506,/10609,/10712 3100 .DA /10816,/10920,/11025,/11130,/11236,/11342,/11449,/11556 3110 .DA /11664,/11772,/11881,/11990,/12100,/12210,/12321,/12432 3120 .DA /12544,/12656,/12769,/12882,/12996,/13110,/13225,/13340 3130 .DA /13456,/13572,/13689,/13806,/13924,/14042,/14161,/14280 3140 .DA /14400,/14520,/14641,/14762,/14884,/15006,/15129,/15252 3150 .DA /15376,/15500,/15625,/15750,/15876,/16002,/16129,/16256 3160 .DA /16384,/16512,/16641,/16770,/16900,/17030,/17161,/17292 3170 .DA /17424,/17556,/17689,/17822,/17956,/18090,/18225,/18360 3180 .DA /18496,/18632,/18769,/18906,/19044,/19182,/19321,/19460 3190 .DA /19600,/19740,/19881,/20022,/20164,/20306,/20449,/20592 3200 .DA /20736,/20880,/21025,/21170,/21316,/21462,/21609,/21756 3210 .DA /21904,/22052,/22201,/22350,/22500,/22650,/22801,/22952 3220 .DA /23104,/23256,/23409,/23562,/23716,/23870,/24025,/24180 3230 .DA /24336,/24492,/24649,/24806,/24964,/25122,/25281,/25440 3240 .DA /25600,/25760,/25921,/26082,/26244,/26406,/26569,/26732 3250 .DA /26896,/27060,/27225,/27390,/27556,/27722,/27889,/28056 3260 .DA /28224,/28392,/28561,/28730,/28900,/29070,/29241,/29412 3270 .DA /29584,/29756,/29929,/30102,/30276,/30450,/30625,/30800 3280 .DA /30976,/31152,/31329,/31506,/31684,/31862,/32041,/32220 3290 .DA /32400,/32580,/32761,/32942,/33124,/33306,/33489,/33672 3300 .DA /33856,/34040,/34225,/34410,/34596,/34782,/34969,/35156 3310 .DA /35344,/35532,/35721,/35910,/36100,/36290,/36481,/36672 3320 .DA /36864,/37056,/37249,/37442,/37636,/37830,/38025,/38220 3330 .DA /38416,/38612,/38809,/39006,/39204,/39402,/39601,/39800 3340 .DA /40000,/40200,/40401,/40602,/40804,/41006,/41209,/41412 3350 .DA /41616,/41820,/42025,/42230,/42436,/42642,/42849,/43056 3360 .DA /43264,/43472,/43681,/43890,/44100,/44310,/44521,/44732 3370 .DA /44944,/45156,/45369,/45582,/45796,/46010,/46225,/46440 3380 .DA /46656,/46872,/47089,/47306,/47524,/47742,/47961,/48180 3390 .DA /48400,/48620,/48841,/49062,/49284,/49506,/49729,/49952 3400 .DA /50176,/50400,/50625,/50850,/51076,/51302,/51529,/51756 3410 .DA /51984,/52212,/52441,/52670,/52900,/53130,/53361,/53592 3420 .DA /53824,/54056,/54289,/54522,/54756,/54990,/55225,/55460 3430 .DA /55696,/55932,/56169,/56406,/56644,/56882,/57121,/57360 3440 .DA /57600,/57840,/58081,/58322,/58564,/58806,/59049,/59292 3450 .DA /59536,/59780,/60025,/60270,/60516,/60762,/61009,/61256 3460 .LIST ON 3470 .DA /61504,/61752,/62001,/62250,/62500,/62750,/63001,/63252 3480 .DA /63504,/63756,/64009,/64262,/64516,/64770,/65025,/65280 3490 *-------------------------------- 3500 .LIF |
| New Hardware for Programming PALs | Bob Sander-Cederlof |
PALs (programmable array logic chips) are to logic circuitry as ROMs are to memory. Most of the new cards coming out these days contain one or more PALs. Engineers write logic equations, feed them into a PAL Assembler, and run the output to a PAL burner. The programmed PAL is then ready to use in a circuit. Until now, you had to buy a PAL development system, either stand-alone or perhaps interfaced to an IBM-alike.
But now, Dynatek Electronics has introduced a new board than slips nicely into an Apple slot for programming 20- and 24-pin PALs. The PALP-701A, for $245, programs 20-pin PALs. The PALP-702A handles both 20- and 24-pin chips, and can also blow the security fuse when you are ready for it. Both of them come with the PAL Assembler software.
Dynatek's PAL Assembler is compatible with Monolithic Memories PALASM. It creates a fuse plot from a PAL source file of Boolean equations. The fuse plot is then used by the PAL Programmer card via on-board firmware to program the PAL. The firmware on the Programmer card can also read un-protected PALs, and verify them. There is also a screen editor for creating, examining, and modifying a fuse plot.
Almost any Apple II system will do. You need at least 16K RAM to use the card, at least 48K and a disk drive to use the PAL Assembler. And who, these days, does not have at LEAST 48K?
If you design and build circuits, you ought to investigate this card. Call Jerry Wang at (312) 255-3469, or write to Dynatek Electronics, Inc., P. O. Box 1567, Arlington Heights, IL 60006. Tell him we sent you!
| Review of Applied Engineering Transwarp | Bob Sander-Cederlof |
We reviewed the M-c-T SpeedDemon accelerator card in AAL of July 1985. At the time the price was $295 from the manufacturer or $199 through Call APPLE. We recently received a promotion sent to software publishers offering wholesale prices if we would advertise the SpeedDemon in conjunction with our software. The suggested price is now $249. (We notice that at least one game publisher took them up on the offer.)
Now Applied Engineering has released their new accelerator card, the Transwarp. Their price is $279 with a 65C02 installed, and an optional upgrade to a fast 65802 for an additional $89. The higher price is probably well justified by the features.
Transwarp includes 256K of high-speed RAM on the card. This compares to 64K on the Titan Accelerator, and a 4K cache on the SpeedDemon. Transwarp will run with the SWYFT card installed, while the others apparently will not.
Transwarp's 256K RAM is effectively divided into four 64K banks. When you power-up your Apple with Transwarp installed, all of the ROM from $D000 through $FFFF is copied into one of the high-speed RAM banks. The rest of this bank is not used. A second bank is used in place of the motherboard RAM. The third and fourth banks are used in place of the first and second banks of AUXMEM, if you have a RAM card such as RAMWORKS installed in the AUX slot. If you have a large RAMWORKS in the auxiliary slot of a //e, any additional banks beyond two will still be usable but at "only" 1 MHz.
When you write data to one of the screen areas (any address $400-$BFF or $2000-$5FFF), the data is "written through" to the motherboard RAM. (The video hardware in the Apple requires that the screen data be in motherboard RAM.) When you read from any of these addresses, the data will be read from the fast Transwarp RAM.
Transwarp keeps track of the state of all the AUXMEM soft switches, as well as the RAMWORKS bank register. All reads from any memory that is supported in the Transwarp RAM will be done at full speed. Reads from and writes to any address in the range $C000-$CFFF will slow down to 1 MHz for one cycle.
There are 16 dip switches on the card, allowing you to configure for most environments. Seven switches indicate which slots must execute code at 1 MHz. Slots designated by switches will slow down the processor for about 1/2 second after any access to either the slot ROM or the slot registers. An Apple disk Controller must run at the slow speed, while most other slots can run faster. Some I/O cards, especially serial cards, must run at slow speed due to internal software-controlled timing. The Transwarp's switches are much more flexible than the SpeedDemon's system of always slowing down for slot 6 and using jumpers to allow a slowdown for slots 4 and 5.
Another seven switches let you indicate which slots (1-7) have RAM cards installed. The two remaining switches let you select the initial speed of the Transwarp card. You can select a default speed of 3.58 MHz, 1.7 MHz, or 1 MHz. This is the speed the card runs at when you power up. You might like the 1.7 MHz speed for making your game software just a LITTLE faster.
Once the Transwarp has taken over, you can switch back and forth between the default speed and 1 MHz by storing either 0 (default speed) or 1 (1 MHz) into $C074. In BASIC this would be POKE to -16268 or 49268 of either 0 or 1.
If you POKE a value of 3 to $C074, Transwarp will be shut down completely; the motherboard processor will take over when you hit CTRL-RESET. In order to turn Transwarp back on, you have to turn the computer off and back on again with the power switch. You also have the option of disabling Transwarp during the power-on cycle, by typing the ESCAPE key within a couple of seconds after turning on the computer.
Transwarp has a 4K EPROM on-board with startup and self-test firmware. Naturally, I disassembled the code to see how it all works. The self-test is initiated by typing a "0" or "9" during the first two seconds. The test checks for the type of processor installed (65C02 or 65802), measures the speed, tests bank switching, and tests RAM. If you are in a //e, you can hold down the Open-Apple key to keep it looping through the speed test.
Transwarp measures its own speed by counting how many cycles it takes for the Vertical Blanking Signal to pass by. This signal is not available on the II or II Plus, so no speed information is tested on the older machines.
We tested Transwarp doing various jobs such as assembling, word processing, and spreadsheet-ing. Everything worked, no glitches, and a lot faster. The speedup factor depends on the amount of disk I/O, screen I/O, and so on. Nothing runs with a full 3.5 or 3.6 speed increase, not even a short timing loop. The very highest factor I could coax out of my board was about 3.3, on a timing loop running at $C00. This loop included a large number of STA instructions, on purpose. When I moved the program to $800, so that the STA instructions were storing into the range slowed down to 1MHz (between $400 and $BFF), the loop only ran 2.0 times faster under Transwarp than under a normal 1 MHz processor.
Why do the advertisements for accelerators claim a 3.6 or larger speedup factor? I think they are rounding up the clock speed of 3.579... to 3.6, and likewise rounding down the Apple's clock speed from 1.023 to 1. That is not the way the IRS likes you to do math.... The actual ratio of the two clock speeds is exactly 3.5, but the mist does not entirely clear yet.
Remember that the Apple stretches one cycle out of every 65 by an amount equal to one cycle of the 7MHz signal. See chapter 3 of Jim Sather's "Understanding the Apple //e" for details. This means the normal Apple runs a hair slower than the clock rate. But also remember that dynamic RAM needs refreshing from time to time. The refresh of the 256K RAM on the Transwarp card occurs once out of every 16 Apple phase 0 (1MHz) clock cycles. During each 16th 1MHz cycle, the Transwarp slows down to 1MHz. This means that in the time a normal Apple would execute 16 clock cycles, the full-speed Transwarp will execute 53 clock cycles. If not for the long refresh cycle, Transwarp would execute 56 cycles during 16 phase 0 cycles. Now 53 divided by 16 is 3.3125, showing that the maximum speedup factor for Transwarp is 3.3125. I don't know for certain, but the Titan Accelerator II probably has the same characteristic. If so, they both run at a full 3.5 times faster for 15 microseconds, slow down for one microsecond, and then take off again.
The SpeedDemon, on the other hand, can run at a full 3.5 times faster for somewhat longer bursts. If every byte needed is in the SpeedDemon cache memory (static RAM, needing no refresh), execution should proceed at 3.5 times normal Apple speed. Normal programs, however, which are long enough to make us worry about speed, will never be entirely inside the cache. In all comparison tests of real software, Transwarp is faster than either SpeedDemon or Titan. SpeedDemon loses due to its cache, and Titan loses because it does not speed up any accesses to AUXMEM.
The S-C Word Processor increased its speed by about 3.2 for compute-bound operations like searching. Interestingly, an operation that is limited by screen output, like inserting characters from the yank buffer, showed almost no increase in speed. In THE Spreadsheet (MagiCalc) the acceleration factor was about 3.1-3.3, running in a II+ with a Viewmaster 80-column card. Our mailing label system, written mostly in Applesoft, showed a pretty consistent 3.3 speedup. Programs which involve disk I/O will not speed up as much, because the disk still spins at the same 300 rpm.
All in all, we think the Transwarp is a good investment: you get a quality product at a reasonable price which significantly enhances the performance of your computer.
| New Book by Tom Weishaar | reviewed by Bob Sander-Cederlof |
A little over a year ago, just before he started the "Open-Apple" newsletter, Tom wrote a book. Info Books has just released it, called "Your Best Interest: A Money Book for the Computer Age." It's not about Apple assembly language, but I cannot resist telling you about it anyway!
The book is about interest rates -- how to understand them, how to calculate them, how they affect you. It was written for people who know how to use a spreadsheet program. All the hard math and books of tables are replaced your favorite calc-alike.
If you remember Tom's DOSTalk column from the much-missed pages of Softalk Magazine, or are familiar with his current Open-Apple newsletter, you know that what he writes is easy to read, fun to read, and WORTH READING.
Seven fascinating chapters lead you to an understanding of how financial transactions really work. He starts with simple percentage calculations, at a level your Junior High children can follow. If you think that is starting too simply, try explaining percentages to YOUR children! But he keeps going....
Have you thought about buying a house recently? Tom shows you how to figure the true cost of an adjustable-rate mortgage, how to compare different financing schemes, and how to protect your money. You'll learn about the tricks money lenders sometimes use to take advantage of unwary investors and borrowers. And all is tied to spreadsheet models you can put into your Apple. I wish I had only known how to do these things when I bought a pickup truck last summer. Or leased a copying machine three years ago. And when we bought some land in the country....
The book is 160 pages slim (172 counting everything), only $9.95 at your favorite book store. And worth a trip! Or call Gerald Rafferty at Info Books, (213) 470-6786. Or write to them at P. O. Box 1018, Santa Monica, CA 90406.
| Which Processor Am I In? | Jim Popenoe |
One of the first programs I wrote after receiving my 65802 chip was one which tells me which microprocessor is in my Apple. Since the 65C02 has instructions not in the 6502, and since the 65802 has all of those and still more, it is possible to tell which is which.
The instructions in the 65802 (or 65816) which are not in the 65C02 are all "no-operation" opcodes in the 65C02. The same is not true for the un-implemented codes in the 6502! Bob S-C detailed what all the un-implemented 6502 opcodes do in the March 1981 issue of AAL. Some of them do really exotic things, but some are in fact NOPs. $80 is a two-byte NOP in the 6502, but a Branch Always (BRA) in the 65C02 and 658xx. Therefore, the BRA opcode can be used to distinguish between the 6502 and higher versions.
The XBA instruction ($EB) is a one-byte no-operation in the 65C02. In the 658xx it exchanges the low and high bytes of the 16-bit A-register. Therefore it can be used to distinguish between the 65C02 and the 658xx processors.
The following program will print out either "6502", "65C02", or "65802" depending on which it finds. A few more tests could distinguish the Rockwell 65C02, which has four opcodes beyond those in 65C02s made by other manufacturers. And a few more might distinguish between a 65802 in my motherboard and a 65816 running in a co-processor card. I'll leave those for interested readers to try.
1000 *SAVE S.WHICH.PROC 1010 .OP 65802 1020 *-------------------------------- 1030 PRBYTE .EQ $FDDA 1040 COUT .EQ $FDED 1050 *-------------------------------- 1060 WHICH.PROCESSOR 1070 LDA #$65 1080 JSR PRBYTE 1090 BRA .1 1100 JMP .2 1110 .1 LDA #"8" 1120 XBA 1130 LDA #"C" 1140 XBA 1150 JSR COUT 1160 .2 LDA #$02 1170 JMP PRBYTE 1180 *-------------------------------- |
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