Antic Magazine 1986 March/Antic_Magazine_1986_03_Antic.atr/bitz.m65

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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 ¢