0250 ; REV.B TO REV.C CONVERTER 0260 ; BY MATTHEW RATCLIFF 0270 ; (c) 1985, ANTIC PUBLISHING 0280 *= $0600 0290 .OPT OBJ 0300 ; 0310 ; PUT CODE INTO PAGE 6 0320 ; 0330 CASINI = $02 ;VECTOR WE WILL STEAL 0340 BOOT = $09 ;CASS/DISK BOOT FLAG 0350 ; SET BIT 1 AND SYSTEM LOOKS FOR 0360 ; POST RESET HANDLER CODE POINTED 0370 ; TO BY CASINI VECTOR. THIS IS 0380 ; HOW RESET ALWAYS GIVES YOU REV.C 0390 ; RAM-BASIC. 0400 GINTLK = $03FA ;EXTERNAL CART? DO NOTHING 0410 RMPNT = $D8 ;ROM/RAM POINTER 0420 COUNT = $DA ;BUG FIX COUNT LOC 0430 PORTB = $D301 ;CONTROL ROM/RAM THRU HERE 0440 BEGBAS = $A000 ;BASIC ROM STARTS HERE 0450 ; 0460 ; STEAL CASSETTE RESET VECTOR 0470 ; AND POINT HERE FOR NEXT RESET. 0480 ; 0490 STEAL LDA # <STEAL 0500 STA CASINI ;MUST RESTORE VECTOR 0510 LDA # >STEAL ;EVERY TIME RESET IS PRESSED 0520 STA CASINI+1 0530 LDA GINTLK ;EXTERNAL CART? 0540 BEQ CNTNU ;IF YES, CONTINUE 0550 RTS ; IF NO, ABORT 0560 CNTNU LDA # <BEGBAS ;POINT TO START OF 0570 STA RMPNT ;BAD BASIC ROM 0580 LDA # >BEGBAS 0590 STA RMPNT+1 0600 BCOPY LDY #0 ;COPY IT TO RAM 0610 LDA PORTB ;BASIC ROM ON PLEASE 0620 AND #$FD ;RESET CONTROL BIT=ON 0630 STA PORTB ;GOT IT 0640 LDA (RMPNT),Y ;GET ROM BYTE 0650 PHA ;SAVE IT 0660 LDA PORTB ;NOW ENABLE THE RAM INSTEAD 0670 ORA #$02 ;SET CONTROL BIT=OFF 0680 STA PORTB ;ROM OFF, RAM ON 0690 PLA ;GET ROM BYTE 0700 STA (RMPNT),Y ;RAM VERSION UPDATED 0710 INC RMPNT 0720 BNE BCOPY 0730 INC RMPNT+1 0740 LDA RMPNT+1 ;DONE COPYING? 0750 CMP #$C0 ;END OF BASIC? 0760 BNE BCOPY ;NOT YET! 0770 ; NOW GO FIX THE BUGS! 0780 FIXBUGS LDX #0 ;BUG TABLE INDEX 0790 LDA #12 ;12 BUGS TO FIX 0800 STA COUNT 0810 FXLOOP LDY #0 ;SETUP RAM POINTERS 0820 LDA FXTBL,X ;GET ADDR LO BYTE 0830 STA RMPNT ;SETUP RAM POINTER 0840 INX 0850 LDA FXTBL,X ;GET ADDR HI BYTE 0860 STA RMPNT+1 0870 INX 0880 LDA FXTBL,X ;GET CORRECT BYTE 0890 STA (RMPNT),Y ;TO FIX THE BUG 0900 INX ;POINT TO NEXT FIX 0910 DEC COUNT 0920 BNE FXLOOP 0930 LDA BOOT ;ALL DONE WITH FIXED RAM-BASIC 0940 ORA #$02 ;RE-HOOK INTO BOOT 0950 STA BOOT ;FOR NEXT RESET KEY-PRESS 0960 RTS 0970 ; 0980 ; ADDRESS,BYTE FIXUP TABLE FOR 0990 ; REV.B TO REV.C CONVERSION! 1000 ; 1010 FXTBL .WORD $A8DF ;ADDRESS 1020 .BYTE 234 ;WAS 202, NOW 234 IN REV.C 1030 .WORD $A8E0 1040 .BYTE 240 ;WAS 208 1050 .WORD $A8E1 1060 .BYTE 17 ;WAS 10 1070 .WORD $A8E2 1080 .BYTE 234 ;WAS 96 1090 ; 1100 ; PEEK (43234)=96 FOR REV.B 1110 ; THAT IS ADDR $A8E2 1120 ; 1130 .WORD $BB29 1140 .BYTE 0 ;WAS 16 1150 .WORD $BFF3 1160 .BYTE 0 ;WAS 44 1170 .WORD $BFF4 1180 .BYTE 0 ;WAS 55 1190 .WORD $BFF5 1200 .BYTE 0 ;WAS 105 1210 .WORD $BFF6 1220 .BYTE 0 ;WAS 110 1230 .WORD $BFF7 1240 .BYTE 0 ;WAS 110 1250 .WORD $BFF8 1260 .BYTE 0 ;WAS 101 1270 .WORD $BFF9 1280 .BYTE 0 ;WAS 114 1290 ; 1300 ; ONLY 12 BYTES DIFFERENCE BETWEEN 1310 ; REV.B & REV.C! 1320 ; 1330 .END
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