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36 lines
527 B
ArmAsm
36 lines
527 B
ArmAsm
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; Ullrich von Bassewitz, 05.08.1998
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; CC65 runtime: sub ints
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.export tossuba0, tossubax
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.import addysp1
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.importzp sp
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.macpack cpu
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; AX = TOS - AX
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tossuba0:
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ldx #0
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tossubax:
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sec
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eor #$FF
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.if (.cpu .bitand CPU_ISET_65SC02)
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adc (sp)
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ldy #1
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.else
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ldy #0
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adc (sp),y ; Subtract low byte
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iny
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.endif
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pha ; Save high byte
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txa
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eor #$FF
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adc (sp),y ; Subtract high byte
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tax ; High byte into X
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pla ; Restore low byte
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jmp addysp1 ; drop TOS
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