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71 lines
1.5 KiB
ArmAsm
71 lines
1.5 KiB
ArmAsm
;
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; Ullrich von Bassewitz, 2003-08-12
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;
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; char* __fastcall__ getcwd (char* buf, size_t size);
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;
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.export _getcwd
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.import popax
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.import __cwd
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.importzp ptr1, ptr2
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.include "errno.inc"
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;--------------------------------------------------------------------------
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.proc _getcwd
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; Remember -size-1 because this simplifies the following loop
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eor #$FF
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sta ptr2
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txa
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eor #$FF
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sta ptr2+1
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jsr popax ; Get buf
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sta ptr1
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stx ptr1+1 ; Save buf
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; Copy __cwd to the given buffer checking the length
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ldy #$00
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loop: inc ptr2
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bne @L1
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inc ptr2+1
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beq overflow
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; Copy one character, end the loop if the zero terminator is reached. We
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; don't support directories longer than 255 characters for now.
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@L1: lda __cwd,y
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sta (ptr1),y
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beq done
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iny
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bne loop
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; For some reason the cwd is longer than 255 characters. This should not
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; happen, we handle it as if the passed buffer was too short.
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;
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; String overflow, return ERANGE
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overflow:
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lda #<ERANGE
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sta __errno
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lda #>ERANGE
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sta __errno+1
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tax ; High byte of ERANGE is zero, return zero
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rts
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; Success, return buf
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done: lda ptr1
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ldx ptr1+1
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rts
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.endproc
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