Added a getcwd function

git-svn-id: svn://svn.cc65.org/cc65/trunk@2275 b7a2c559-68d2-44c3-8de9-860c34a00d81
2003-08-12 13:51:11 +00:00
parent 20e805a124
commit 8bfaa09b77
4 changed files with 85 additions and 3 deletions
--- a/libsrc/common/getcwd.s
+++ b/libsrc/common/getcwd.s
@@ -0,0 +1,64 @@
+;
+; 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     #$00
+loop:   inc     ptr2
+        bne     @L1
+        inc     ptr2+1
+        beq     overflow
+
+; Copy one character, end the loop if the zero terminator is reached
+
+@L1:    lda     __cwd,y
+        sta     (ptr1),y
+        bne     loop
+
+; Current working dir copied ok, A contains zero
+
+        tax                     ; Return zero in a/x
+        rts
+
+; String overflow, return ERANGE
+
+overflow:
+        lda     #<ERANGE
+        sta     __errno
+        lda     #>ERANGE
+        sta     __errno+1
+        lda     #$FF
+        tax                     ; Return -1
+        rts
+
+.endproc
+
+