61 lines
874 B
ArmAsm
61 lines
874 B
ArmAsm
;=========================================================
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; gr_copy_at_offset, 40x48 version
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;=========================================================
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; copy $1000 + line offset to $c00
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; offset is in Y
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; FIXME: smaller code if put offset in A instead?
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gr_copy_to_offset:
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lda #0
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sta TEMPY
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gr_copy_offset_outer_loop:
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; calculate source
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lda gr_offsets_h,Y
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clc
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adc #$c
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sta gr_copy_offset_smc_src+2
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lda gr_offsets_l,Y
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sta gr_copy_offset_smc_src+1
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tya
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pha
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; calculate destination
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lda TEMPY
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tay
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lda gr_offsets_h,Y
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clc
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adc #$8
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sta gr_copy_offset_smc_dst+2
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lda gr_offsets_l,Y
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sta gr_copy_offset_smc_dst+1
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ldx #0
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gr_copy_offset_line_loop:
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gr_copy_offset_smc_src:
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lda $1000,X
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gr_copy_offset_smc_dst:
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sta $c00,X
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inx
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cpx #40
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bne gr_copy_offset_line_loop
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inc TEMPY
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pla
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tay
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iny
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cpy #24
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bne gr_copy_offset_outer_loop
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rts ; 6
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