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67 lines
828 B
ArmAsm
67 lines
828 B
ArmAsm
.define EQU =
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PTR EQU $06
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PTRH EQU $07
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WRAPL EQU $08
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WRAPH EQU $09
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SIZEL EQU $0A
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SIZEH EQU $0B
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tx_copy:
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lda #0 ; always copying from 0x4000
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sta PTR
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lda #$40
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sta PTR+1
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ldx #SIZEH ; number of 256-byte blocks
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beq copy_remainder ; if none, skip ahead
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ldy #0
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copy256:
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lda (PTR),y
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sta $C0B7 ; change based on uthernet slot
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cmp WRAPH,x
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bne nowrap256
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cmp WRAPL,y
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bne nowrap256
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lda #$40
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sta $C0B5
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lda #$00
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sta $C0B6 ; wrap tx buffer address to 0x4000
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nowrap256:
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iny
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bne copy256
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inc PTR+1 ; update 16-bit pointer
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dex ; finish a 256 byte block
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bne copy256
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ldx #SIZEL
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copy_remainder:
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lda (PTR),y
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sta $C0B7 ; change based on uthernet slot
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cmp WRAPL,y
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bne nowrap_r
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lda #$40
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sta $C0B5
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lda #$00
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sta $C0B6 ; wrap tx buffer address to 0x4000
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nowrap_r:
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iny
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dex
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bne copy_remainder
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rts
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