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63 lines
1.2 KiB
ArmAsm
63 lines
1.2 KiB
ArmAsm
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; 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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org $1000
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ldy #END-AFTER
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copy lda BEFORE,y
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sta AFTER,y
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dey
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bmi done
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bpl copy
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dfb $00
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stuff asc 'hello!'
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done jmp AFTER
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BEFORE
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org $2000
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AFTER
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lda INPUT ;expecting 0-3
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cmp #4
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blt :valid
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lda #4 ;error message
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:valid asl A
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tax
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lda stringtab,x ;set load to address
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sta _load+1
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lda stringtab+1,x
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sta _load+2
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ldy #12 ;fixed-width strings
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_load lda $0000,y ;self-modifying code
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ora #$80
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sta OUTPUT,y
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dey
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bpl _load
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rts
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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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dw stringX
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dfb $00
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string0 asc 'string zero '
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string1 asc 'string one '
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string2 asc 'string two '
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string3 asc 'string three '
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stringX asc 'invalid index'
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END
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