0100 ; FAST STACK›0110 ; BY BILL BODENSTEIN›0120 ; (c)1987, ANTIC PUBLISHING›0130 ;›0140 ;EQUATES›0150 ;›0160 PORTB = $D301   ;Toggle ROM›0170 BASIC.ON = 253›0180 BASIC.OFF = 255›0190 ;›0200 LDA =   165     ;Decimal opcode›0210 STMCUR = $8A    ;BASIC line ptr›0220 FORLN = $A0     ;Line # put here›0230 ;›0240 PUT.PATCH1 = $A071 ;Patch after›0250 ;                   STOP/END›0260 PUT.PATCH2 = PUT.PATCH1+5›0270 ;›0280 ;               Relocatable, but›0290     *=  $0600   ;could be called›0300 ;                via USR(1536)›0310 STARTCODE›0320     PLA         ;Remove # args›0330 COPY.BASIC›0340     LDA #$A0    ;Start of BASIC›0350     STA $E1›0360     LDA #$00›0370     STA $E0›0380     TAY ›0390 LOOP1›0400     LDX #BASIC.ON›0410     STX PORTB   ;BASIC ROM on›0420     LDA ($E0),Y ;Get a byte›0430     LDX #BASIC.OFF›0440     STX PORTB   ;BASIC RAM on›0450     STA ($E0),Y ;Copy byte›0460     INY ›0470     BNE LOOP1   ;And loop›0480 ;›0490     INC $E1›0500     LDA $E1›0510     CMP #192    ;Until all moved›0520     BNE LOOP1›0530 ;›0540 MODIFY.BASIC›0550     LDA #STMCUR+1 ;LDA ($8A),Y=>›0560     STA $B6C6   ;  LDA  $8B›0570     LDA #LDA    ;  and LDA $8A›0580     STA $B6C0›0590     STA $B6C5›0600 ;›0610     LDA # <PUT.PATCH2›0620     STA $BDCC   ;Change JSR from›0630     LDA # >PUT.PATCH2›0640     STA $BDCD   ;$B816 to patch2›0650 ;›0660 ;Install patch to re-enable ROM›0670 ;at STOP or END, and patch to›0680 ;change line pointer.›0690     LDX #ENDCODE-PATCH1-1›0700     LDY #ENDCODE-STARTCODE-1›0710 LOOP2›0720     LDA ($D4),Y ;Move bytes from›0730     STA PUT.PATCH1,X ;USR code›0740     DEY ›0750     DEX ›0760     BPL LOOP2   ;Done when patch›0770 ;›0780     RTS         ;installed›0790 ;›0800 ;Patches to be placed in code›0810 ;after STOP/END. Note: once›0820 ;BASIC ROM is enabled by patch1,›0830 ;patch2 won't be executed.›0840 PATCH1›0850     LDX #BASIC.ON›0860     STX PORTB›0870 ;›0880 PATCH2›0890     LDA FORLN   ;Ln addr is here›0900     STA STMCUR  ;Point to it›0910     LDA FORLN+1›0920     STA STMCUR+1›0930     LDY #2      ;(Rest is the›0940     LDA (STMCUR),Y ; same)›0950     STA $9F›0960     CLC ›0970     RTS ›0980 ENDCODE›