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https://github.com/nathanriggs/AppleIIAsm-Collection.git
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89 lines
2.3 KiB
NASM
89 lines
2.3 KiB
NASM
*
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*``````````````````````````````*
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* HEAD.REQUIRED *
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* *
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* THIS HEADER MUST BE THE *
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* INCLUDED BEFORE ANY OTHER *
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* CODE IN ORDER FOR THE PROPER *
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* FUNCTIONING OF ANY LIBRARY. *
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* *
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* AUTHOR: NATHAN RIGGS *
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* CONTACT: NATHAN.RIGGS@ *
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* OUTLOOK.COM *
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* *
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* DATE: 04-JUN-2021 *
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* ASSEMBLER: MERLIN 8 PRO *
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* OS: DOS 3.3 *
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* *
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* SIZE: 305 BYTES *
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*,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,*
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*
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*``````````````````````````````*
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* CONSTANTS *
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*,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,*
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*
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** ZERO PAGE WORD LOCATIONS
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*
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ZPW1 EQU $06 ; AND $07
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ZPW2 EQU $08 ; AND $09
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ZPW3 EQU $EB ; AND $EC
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ZPW4 EQU $ED ; AND $EE
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ZPW5 EQU $FA ; AND $FB
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ZPW6 EQU $FC ; AND $FD
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ZPWSYS EQU $FE ; AND $FF
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*
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** ZERO PAGE BYTE LOCATIONS
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*
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ZPB1 EQU $19 ; USED TO BACKUP .Y
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ZPB2 EQU $1E
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ZPB3 EQU $EF
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ZPB4 EQU $E3
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*
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REENTRY EQU $3D0
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*
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PROMPT EQU $33 ; DOS PROMPT CHARACTER
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COLDENT EQU $03D3 ; COLD ENTRY TO DOS
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SRESET EQU $03F2 ; SOFT RESET
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PRNTAX EQU $F941 ; PRINT HEX VALS OF A,X REGISTERS
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BELL EQU $FBE4 ; RING MY BELL
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IOSAVE EQU $FF4A ; SAVE CURRENT STATE OF REGISTERS
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IOREST EQU $FF3F ; RESTORE OLD STATE OF REGISTERS
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*
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BITON0 EQU $01 ; FOR AND MASKING
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BITON1 EQU $02 ; TO CHECK IF BIT IS ON
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BITON2 EQU $04
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BITON3 EQU $08
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BITON4 EQU $10
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BITON5 EQU $20
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BITON6 EQU $40
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BITON7 EQU $80
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*
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*``````````````````````````````*
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* DEDICATED MEMORY *
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*,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,*
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*
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JMP _MAINSTART
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*
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** 16 BYTES FOR PASSING VARIABLES. THIS WOULD
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** NORMALLY HAPPEN WITH ZERO PAGE LOCATIONS, AT
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** LEAST IDEALLY, BUT SOMETIMES EXTRA SPACE MIGHT
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** BE NECESSARY.
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*
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PASSTAB DS 16
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*
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** 30 BYTES FOR DEDICATED VARIABLE STORAGE. AGAIN, NOT
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** ALWAYS NEEDED SINCE MOST VARIABLES ARE HELD ON THE
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** ZERO PAGE, BUT SOMETIMES NECESSARY.
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*
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VARTAB DS 30
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*
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** 256 BYTES DEDICATED TO RETURN
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** VALUES OF VARIABLE LENGTH; CAN BE
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** MODIFIED TO SUIT SMALLER OR LARGER
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** NEEDS.
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*
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RETLEN DS 1 ; RETURN VALUE BYTE LENGTH
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RETURN DS 255
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*
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_MAINSTART
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