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eb99a716f1
Added an inline data formatting section to Tutorial2. Added a new section on extension scripts, using Scripts/Sample as the code.
115 lines
2.1 KiB
ArmAsm
115 lines
2.1 KiB
ArmAsm
; Copyright 2018 faddenSoft. All Rights Reserved.
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; See the LICENSE.txt file for distribution terms (Apache 2.0).
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;
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; Assembler: Merlin 32
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INPUT equ $3000
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OUTPUT equ $0400
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PTR1 equ $02
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PTR2 equ $04
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START equ $2000
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org START-2
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dw START
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sec
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ror A
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bmi skipstr
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string0 asc 'first string',00
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string1 asc 'another string',00
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string2 asc 'string the third',00
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string3 asc 'last string',00
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skipstr
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lda #<stringtab
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sta PTR1
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lda #>stringtab
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sta PTR1+1
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jsr thing
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and #$03
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asl A
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tay
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lda (PTR1),y
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sta PTR2
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iny
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lda (PTR1),y
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sta PTR2+1
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ldy #$ff
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]loop iny
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lda (PTR2),y
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beq copydone
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ora #$80
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sta OUTPUT,y
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bne ]loop ;always taken
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stringtab
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dw string0
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dw string1
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dw string2
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dw string3
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copydone
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jsr PrintInlineZString
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asc 'Embedded!',00
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lda #$ff ;self-modifying code example
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sta _mod+1
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_mod lda #$00
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bne skipbrk
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middat ds 4
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outdat ds 1
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skipbrk
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lda middat ;nearby-label example
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ora middat+1
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and middat+2
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eor middat+3
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ldx #$00 ;embedded instruction example
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dfb $2c
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rebr ldx #$01
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sta outdat
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lda INPUT
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lsr A
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lsr A
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lsr A
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lsr A
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sta INPUT
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bne rebr
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rts
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thing
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lda INPUT
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rts
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PrintInlineZString
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pla
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sta PTR1
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pla
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sta PTR1+1
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ldy #$01
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:loop lda (PTR1),Y
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beq strend
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ora #$80
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jsr $FDED
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iny
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bne :loop
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strend tya
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clc
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adc PTR1
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sta PTR1
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lda PTR1+1
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adc #$00
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pha
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lda PTR1
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pha
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rts
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