37 lines
695 B
ArmAsm
37 lines
695 B
ArmAsm
include "includes.i"
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xdef SwitchBuffers
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SwitchBuffers:
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;; offscreen - bitplane address
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movem.l d0/a0-a1,-(sp)
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move.l offscreen,a0
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move.l onscreen,offscreen
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move.l a0,onscreen
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moveq.l #LEFT_SCREEN_BUFFER_BYTES,d0
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move.l a0,a1
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lea copperListBplPtr,a0
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jsr PokeBitplanePointers
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movem.l (sp)+,d0/a0-a1
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rts
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PokeBitplanePointers:
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; d0 = frame offset in bytes
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; a0 = BPLP copper list address
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; a1 = bitplanes pointer
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movem.l d0-a6,-(sp)
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add.l d0,a1 ; Offset for odd/even frames
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moveq #SCREEN_BIT_DEPTH-1,d0
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.bitplaneloop:
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move.l a1,d1
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move.w d1,2(a0)
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swap d1
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move.w d1,6(a0)
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lea BITPLANE_WIDTH_BYTES(a1),a1
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addq #8,a0
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dbra d0,.bitplaneloop
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movem.l (sp)+,d0-a6
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rts
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