PSC Simple Debugger#
This is a very simple debugger I have written years ago. It has been used to figure out the hotspots of a program or to slow down the program to be examined.
The "BUG.COM" executable will install a VBI with a wait loop. This loop is slowing down the Atari and thus other programs running. It can be adjusted with "START" and "SELECT". In the top line the tool will display the current CPU instruction pointer. This instruction pointer can be copied to the field on the right with the "OPTION" key (e.g. to examine a specific code area with a hardware monitor such as BiboMon, QMeg or Turbo-Freezer).
Disk#
A simple 6502 debugger/sbug6502.atr
Source#
00010 .LI OFF 00020 *************************** 00030 * PSC DEBUGGER V.1 * 00040 *************************** 00050 ; 00060 CASINI = $02 00070 BOOT = $09 00080 CONSOL = $D01F 00090 SDLST = $0230 00100 HLPFLG = $2DC 00110 VCOUNT = $D40B 00111 BZAHL = $238 00120 ; 00130 ; OS ADRESSEN 00140 ; 00150 SETVBV = $E45C 00160 XITVBV = $E462 00170 ; 00180 ; 00190 .OF "D:BUG.COM" 00200 .OR $400 00210 ; 00220 HLPMEM .HX 000000000000 00240 DL .HX 707042 00250 .DA TEXT 00260 .HX 0001 00270 DLEND .HX 0000 00280 TEXT .AT "\240–”√≠¬’«¸¡√‘\240®∞∞∞∞∞©Ωæ®∞∞∞∞∞©¸ƒ≈î∞∞∞∞∞©" 00290 DECLO .HX 10E8640A 00300 DECHI .HX 27030000 00310 ZIFFER .AT "00000" 00320 DELAY .HX 77 00330 ; 00340 ; 00350 ; 00360 ; 00370 X 00380 LDA #X 00390 STA CASINI 00400 LDA /X 00410 STA CASINI+1 00420 ; 00430 LDA BOOT 00440 ORA #$02 00450 STA BOOT 00460 ; 00470 LDA #$04 00480 BIT CONSOL 00490 BNE SETVBI 00500 RTS 00510 ; 00520 SETVBI 00530 LDY #START 00540 LDX /START 00550 LDA #$07 00560 JSR SETVBV 00570 RTS 00580 ; 00590 .OR $0600 00600 ; 00610 START LDA SDLST+1 00620 CMP /DL 00630 BEQ BUG 00640 LDA SDLST 00650 CLC 00660 ADC #$03 00670 STA DLEND 00680 LDA SDLST+1 00690 ADC #$00 00700 STA DLEND+1 00710 LDA #DL 00720 STA SDLST 00730 LDA /DL 00740 STA SDLST+1 00750 ; 00760 BUG 00770 LDX #6 00780 .1 PLA 00790 STA HLPMEM-1,X 00800 DEX 00810 BNE .1 00820 LDX HLPMEM+1 00830 LDA HLPMEM 00840 JSR BINDEZ 00850 ; 00860 XDSPL 00870 LDX #5 00880 LDY #$12 00890 JSR DSPL2 00900 ; 00910 LDA CONSOL 00920 CMP #6 00930 BNE RESTORE 00940 LDX #5 00950 LDY #$1B 00960 JSR DSPL2 00970 ; 00980 RESTORE 00990 ; 01000 LDX #0 01010 .1 LDA HLPMEM,X 01020 PHA 01030 INX 01040 CPX #6 01050 BNE .1 01060 LDA DELAY 01070 LDX #0 01080 JSR BINDEZ 01090 LDX #5 01100 LDY #$26 01110 JSR DSPL2 01120 DELMIN 01130 LDA CONSOL 01140 CMP #5 01150 BNE DELPL 01160 LDA DELAY 01170 CMP #$10 01180 BMI DELPL 01190 DEC DELAY 01200 DELPL 01210 LDA CONSOL 01220 CMP #3 01230 BNE WAIT 01240 LDA DELAY 01250 CMP #$7B 01260 BPL WAIT 01270 INC DELAY 01280 WAIT 01290 LDA DELAY 01300 .1 CMP VCOUNT 01310 BNE WAIT 01320 JMP XITVBV 01330 ------------------------------ 01340 BINDEZ 01350 STA BZAHL 01360 STX BZAHL+1 01370 LDX #4 01380 VORBES 01390 LDA #$10 01400 STA ZIFFER,X 01410 DEX 01420 BPL VORBES 01430 LDX #0 01440 STELLE 01450 LDA BZAHL+1 01460 CMP DECHI,X 01470 BNE TSTHI 01480 LDA BZAHL 01490 CMP DECLO,X 01500 TSTHI 01510 BCC KLEINER 01520 SEC 01530 LDA BZAHL 01540 SBC DECLO,X 01550 STA BZAHL 01560 LDA BZAHL+1 01570 SBC DECHI,X 01580 STA BZAHL+1 01590 INC ZIFFER,X 01600 JMP STELLE 01610 KLEINER 01620 INX 01630 CPX #4 01640 BNE STELLE 01650 CLC 01660 LDA BZAHL 01670 ADC ZIFFER+4 01680 STA ZIFFER+4 01690 RTS 01700 ------------------------------ 01710 DSPL2 01720 LDA ZIFFER-1,X 01730 ORA #$80 01740 STA TEXT,Y 01750 DEY 01760 DEX 01770 BNE DSPL2 01780 RTS 01790 ------------------------------ 01800 .OR $2E0 01810 .DA X 01820 ------------------------------