* *``````````````````````````````* * ZMSAVE :: SAVE 0-PAGE FREE * *- -* * STORES THE VALUES IN THE * * LITTLE FREE SPACE ON THE * * ZERO PAGE AT AN ALTERNATE * * MEMORY LOCATION TO BE * * RETRIEVED AND RESTORED AT A * * LATER POINT. * *- -* * CLOBBERS: * * * * FLAGS: ????---- REG: AXYM * *- -* * CYCLES: ??? * * SIZE: * *- -* * USAGE: * * * * LDA #>$6A00 * * PHA * * LDA #<$6A00 * * PHA * * JSR ZMSAVE * *- -* * ENTRY * * * * TOP OF STACK * * * * LOW BYTE OF RETURN ADDRESS * * HI BYTE OF RETURN ADDRESS * * LOW BYTE OF DESTINATION * * HIGH BYTE OF DESTINATION * *- -* * EXIT * * * * TOP OF STACK * * * * LOW BYTE OF RETURN ADDRESS * * HI BYTE OF RETURN ADDRESS * * * * Y = TRASH * * X = TRASH * * A = LOW BYTE OF RET ADDR * *,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,* * ZMSAVE * ** LOAD ADDR1 ZERO PAGE AREA FIRST, ** SINCE WE'LL BE USING THAT * ** NOTE THAT THIS SHOULD ALWAYS BE ** $06 AND $07, OR ELSE CODE WILL ** HAVE TO CHANGE. * LDX ADDR1 LDY ADDR1+1 * ** SAVE RETURN ADDRESS * PLA STA :RETADR ; LOCAL BECAUSE RETADDR PLA ; IS STORED ON ZERO PAGE STA :RETADR+1 * ** GET PARAMETERS * PLA STA ADDR1 PLA STA ADDR1+1 * ** COPY ZERO PAGE TO SPECIFIED ** NON-ZERO LOCATION (ONLY THE ** FREE ONES..) * TYA ; STORE ADDR1 VALS LDY #1 ; FIRST STA (ADDR1),Y LDY #0 TXA STA (ADDR1),Y LDY #2 LDA $08 STA (ADDR1),Y INY LDA $09 STA (ADDR1),Y INY LDA $19 STA (ADDR1),Y INY LDA $1E STA (ADDR1),Y INY LDA $E3 STA (ADDR1),Y INY LDA $EB STA (ADDR1),Y INY LDA $EC STA (ADDR1),Y INY LDA $ED STA (ADDR1),Y INY LDA $EE STA (ADDR1),Y INY LDA $EF STA (ADDR1),Y INY LDA $FA STA (ADDR1),Y INY LDA $FB STA (ADDR1),Y INY LDA $FC STA (ADDR1),Y INY LDA $FD STA (ADDR1),Y INY LDA $FE STA (ADDR1),Y INY LDA $FF STA (ADDR1),Y * ** RESTORE RETURN ADDRESS * LDA :RETADR+1 PHA LDA :RETADR PHA * RTS * ** DATA * :RETADR DS 2 *