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48 lines
735 B
ArmAsm
48 lines
735 B
ArmAsm
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; Ullrich von Bassewitz, 31.05.1998
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;
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; char* strrchr (const char* s, int c);
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;
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.export _strrchr
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.import popax
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.importzp ptr1, ptr2, tmp1
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_strrchr:
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sta tmp1 ; Save c
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jsr popax ; get s
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sta ptr1
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stx ptr1+1
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lda #0 ; function result = NULL
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sta ptr2
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sta ptr2+1
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tay
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L1: lda (ptr1),y ; get next char
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beq L3 ; jump if end of string
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cmp tmp1 ; found?
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bne L2 ; jump if no
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; Remember a pointer to the character
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tya
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clc
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adc ptr1
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sta ptr2
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lda ptr1+1
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adc #$00
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sta ptr2+1
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; Next char
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L2: iny
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bne L1
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inc ptr1+1
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bne L1 ; jump always
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; Return the pointer to the last occurrence
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L3: lda ptr2
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ldx ptr2+1
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rts
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