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https://github.com/sehugg/8bitworkshop.git
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55 lines
1.1 KiB
Plaintext
55 lines
1.1 KiB
Plaintext
.export _copyxdata
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.import __XDATA_LOAD__, __XDATA_RUN__, __XDATA_SIZE__
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.importzp ptr1, ptr2, tmp1
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.code
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_copyxdata:
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lda #<__XDATA_LOAD__ ; Source pointer
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sta ptr1
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lda #>__XDATA_LOAD__
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sta ptr1+1
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lda #<__XDATA_RUN__ ; Target pointer
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sta ptr2
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lda #>__XDATA_RUN__
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ora #$04 ; write port
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sta ptr2+1
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ldx #<~__XDATA_SIZE__
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lda #>~__XDATA_SIZE__ ; Use -(__DATASIZE__+1)
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sta tmp1
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ldy #$00
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; Copy loop
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@L1: inx
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beq @L3
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@L2:
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lda #0
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sta $3F ; select ROM0
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lda (ptr1),y
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pha
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lda #0
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sta $3E ; select RAM0
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pla
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sta (ptr2),y
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iny
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bne @L1
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inc ptr1+1
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inc ptr2+1 ; Bump pointers
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bne @L1 ; Branch always (hopefully)
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; Bump the high counter byte
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@L3: inc tmp1
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bne @L2
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; Done
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lda #0
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sta $3F ; select ROM0
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rts
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