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63 lines
717 B
ArmAsm
63 lines
717 B
ArmAsm
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; Ullrich von Bassewitz, 09.12.1998
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;
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; void __fastcall__ _swap (void* p, void* q, size_t size);
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;
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.export __swap
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.import popax
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.importzp ptr1, ptr2, ptr3
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__swap: sta ptr3 ; Save size
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stx ptr3+1
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jsr popax ; Get q
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sta ptr2
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stx ptr2+1
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jsr popax ; Get p
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sta ptr1
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stx ptr1+1
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; Prepare for swap
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ldy #$00
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; Swap 256 byte blocks
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ldx ptr3+1
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beq @L2
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@L1: lda (ptr1),y
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tax
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lda (ptr2),y
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sta (ptr1),y
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txa
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sta (ptr2),y
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iny
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bne @L1
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dec ptr3+1
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bne @L1
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; Swap remaining bytes (Y is zero)
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@L2: ldx ptr3
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beq @L9
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@L3: lda (ptr1),y
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tax
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lda (ptr2),y
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sta (ptr1),y
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txa
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sta (ptr2),y
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iny
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dec ptr3
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bne @L3
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; Done
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@L9: rts
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