mirror of
https://github.com/a2-4am/passport.git
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80 lines
1.7 KiB
Plaintext
Executable File
80 lines
1.7 KiB
Plaintext
Executable File
;-------------------------------
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; modify subroutine
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; in: A = starting address (high byte)
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; X = starting address (low byte)
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; Y = string length
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; stack = string to set
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; out $BASEPAGE buffer changed
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; $gPatchCount++
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; $modsrc zero page clobbered
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; $moddest zero page clobbered
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; stack set to return to
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; code after string
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; A,X preserved
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; Y clobbered
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; oVerflow bit clear
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; all other flags clobbered
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;-------------------------------
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!zone {
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modify
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sta gDisplayBytes
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clc
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adc #BASEPAGE
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sta moddest+1
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stx moddest
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stx gDisplayBytes+1
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pla
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sta modsrc
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pla
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sta modsrc+1
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tax
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tya
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clc
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adc modsrc
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bcc .noinc
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inx
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.noinc
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sta tmp
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txa
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pha
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lda tmp
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pha
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sty modtmp
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bit gMode
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bpl .exitnomod ; verify mode -> no modify
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bvc .exitnomod ; demuffin mode -> no modify
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lda #s_modify
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jsr PrintByID
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ldy #0
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.dest
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lda (moddest),y
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jsr PrintByte
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iny
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cpy modtmp
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bne .dest
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lda #s_modifyto
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jsr PrintByID
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ldy #0
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.src
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iny
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lda (modsrc),y
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jsr PrintByte
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cpy modtmp
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bne .src
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lda #$8D
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jsr PrintA
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bvc +
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.mod
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sta (moddest),y
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+ lda (modsrc),y
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dey
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bpl .mod
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.exit
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inc gPatchCount
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.exitnomod
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lda gDisplayBytes
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ldx moddest
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clv
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rts
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}
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