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51 lines
858 B
ArmAsm
51 lines
858 B
ArmAsm
;
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; Ullrich von Bassewitz, 14.09.2001
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;
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.export _peekbsys, _peekwsys
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.importzp ptr1
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.include "cbm510.inc"
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; ------------------------------------------------------------------------
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; unsigned char __fastcall__ peekbsys (unsigned addr);
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.proc _peekbsys
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sta ptr1 ; Store argument pointer
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stx ptr1+1
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ldx IndReg
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lda #$0F
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sta IndReg
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ldy #$00
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lda (ptr1),y
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stx IndReg
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ldx #$00 ; Extend to word
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rts
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.endproc
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; ------------------------------------------------------------------------
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; unsigned __fastcall__ peekwsys (unsigned addr);
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.proc _peekwsys
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sta ptr1 ; Store argument pointer
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stx ptr1+1
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ldx IndReg
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lda #$0F
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sta IndReg
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ldy #$00
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lda (ptr1),y ; Get low byte
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pha
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iny
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lda (ptr1),y ; Get high byte
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stx IndReg
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tax ; High byte -> X
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pla ; Low byte -> A
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rts
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.endproc
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