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cc65/libsrc/common/getcwd.s
cuz 6fcf735744 Fixes to the code just written
git-svn-id: svn://svn.cc65.org/cc65/trunk@2276 b7a2c559-68d2-44c3-8de9-860c34a00d81
2003-08-12 13:58:17 +00:00

71 lines
1.5 KiB
ArmAsm

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