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36 lines
818 B
ArmAsm
36 lines
818 B
ArmAsm
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; Ullrich von Bassewitz, 26.10.2000
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; CC65 runtime: Push value in a/x onto the stack
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;
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.export push0, pusha0, pushax
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.importzp sp
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push0: lda #0
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pusha0: ldx #0
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; This function is used *a lot*, so don't call any subroutines here.
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; Beware: The value in ax must not be changed by this function!
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; Beware^2: The optimizer knows about the value of Y after the function
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; returns!
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.proc pushax
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pha ; (3)
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lda sp ; (6)
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sec ; (8)
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sbc #2 ; (10)
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sta sp ; (13)
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bcs @L1 ; (17)
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dec sp+1 ; (+5)
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@L1: ldy #1 ; (19)
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txa ; (21)
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sta (sp),y ; (27)
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pla ; (31)
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dey ; (33)
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sta (sp),y ; (38)
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rts ; (44)
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.endproc
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