10 ; BITZ, LISTING 2›20 ; BY DON LEBOW›30 ; (c) 1985, ANTIC PUBLISHING›40 ;›50       *=  $0600›60 ;›70 ;EQUATES...z page free bytes›80 ;›90 FIRST =   $CB     ;first number›0100 SECOND = $CC    ;optional mask›0110 RESULT = $CD    ;what we got›0120 FLAGS = $CE     ;status register›0130 FLAGOPT = $CF   ;user option›0140 STRING = $D0    ;string address pointer›0150 ;›0160 ;MODULE 1 (USR 1536....)›0170 ;The Bit Shifter›0180 ;›0190     PLA         ;Pop argument count›0200     CMP #2      ;2 means 2 parameters passed›0210     BEQ DOUBLE  ;so go to double byte routine›0220 ;›0230 ;One byte routine›0240 ;›0250     LDA FLAGOPT ;carry option›0260     BEQ CLEAR   ;0 means user has specified 'clear carry'›0270     LDA FLAGS   ;otherwise, get the old status register›0280     PHA         ;push it›0290     PLP         ;pull it to current status›0300     JMP DOTARGET ;detour around the CLC instruction›0310 ;›0320 CLEAR›0330     CLC ›0340 ;›0350 DOTARGET›0360     PLA ›0370     PLA         ;target byte›0380     NOP         ;opcode poked from Basic:  'accumulator' mode›0390     STA RESULT  ;save new byte›0400 ;›0410 ;Get the flags and return›0420 ;›0430 RETURN›0440     PHP         ;push Status Register›0450     PLA         ;get it back›0460     STA FLAGS   ;put it where we can get at it›0470     RTS         ;done›0480 ;›0490 ;›0500 ;Double byte routine›0510 ;›0520 ;›0530 DOUBLE›0540     CLC         ;default clear›0550     PLA ›0560     PLA ›0570     STA FIRST   ;target›0580     PLA ›0590     PLA ›0600     STA SECOND  ;mask›0610     LDA FIRST›0620     NOP         ;opcode poked from Basic:'Zero Page' mode›0630     .BYTE SECOND ;z page mask›0640     STA RESULT  ;save result›0650     JMP RETURN  ;common return›0660 ;›0670 ;›0680 ;MODULE 2 (USR 1581,ADR(B$),NUM)›0690 ;Byte to Binary String for Basic›0700 ;›0710     PLA         ;pop argument count›0720     PLA ›0730     STA STRING+1 ;hi byte of string address›0740     PLA ›0750     STA STRING  ;and lo›0760     PLA ›0770     PLA         ;number to convert›0780     LDY #7      ;index string›0790 ROTATE›0800     LSR A       ;shift right to carry›0810     PHA         ;save current value›0820     BCC ZERO    ;zero in carry flag›0830 ;›0840 ;Put "1" in string›0850 ;›0860 ONE›0870     LDA #'1›0880     STA (STRING),Y›0890     JMP NEXT›0900 ;›0910 ;Put "O" in string›0920 ;›0930 ZERO›0940     LDA #'O›0950     STA (STRING),Y›0960 ;›0970 ;Next bit›0980 ;›0990 NEXT›1000     PLA         ;get the current value back›1010     DEY         ;decrement index›1020     BPL ROTATE  ;done all 8 bits?›1030 ;›1040 ;All finished›1050 ;›1060     RTS ›