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36 lines
809 B
ArmAsm
36 lines
809 B
ArmAsm
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; Ullrich von Bassewitz, 25.11.2002
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; CC65 runtime: Swap 2 bytes of register variable space
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;
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.export regswap2
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.importzp sp, regbank
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.proc regswap2
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; First byte
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lda regbank,x ; Get old value
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pha ; Save it
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lda (sp),y ; Get stack loc
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sta regbank,x ; Store new value
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pla
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sta (sp),y ; Store old value
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; Second byte
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iny
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lda regbank+1,x ; Get old value
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pha ; Save it
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lda (sp),y ; Get stack loc
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sta regbank+1,x ; Store new value
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pla
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sta (sp),y ; Store old value
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rts
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.endproc
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