Implemented __syschdir on CBM. As getcwd returns a cached directory any direct access to __curunit would cause inconsistencies. Therefore __curunit was renamed to curunit to prohibit user access.

git-svn-id: svn://svn.cc65.org/cc65/trunk@5857 b7a2c559-68d2-44c3-8de9-860c34a00d81

include/cbm.h

@@ -81,10 +81,9 @@
 
 
 
-/* The file stream implementation and the POSIX I/O functions will use the
- * following variables to determine the file type and the disk unit to use.
+/* The file stream implementation and the POSIX I/O functions will
+ * use the following variable to determine the file type to use.
  */
-extern unsigned char _curunit;  /* Defaults to current when program started */
 extern char _filetype;          /* Defaults to 's' */
 
 

libsrc/cbm/Makefile

@@ -90,6 +90,7 @@ S_OBJS =	c_acptr.o	\
 		rewinddir.o	\
 		rwcommon.o	\
 		scratch.o	\
+		syschdir.o	\
 		sysremove.o	\
 		sysrename.o	\
 		telldir.o	\
@@ -109,4 +110,3 @@ clean:
 	@$(RM) *~ *.bck $(C_OBJS:.o=.s) $(C_OBJS) $(S_OBJS)
 
 zap:	clean
-

libsrc/cbm/filename.s

@@ -9,7 +9,7 @@
         .export         fnunit, fnlen, fnisfile, fncmd, fnbuf
 
         .import         SETNAM
-        .import         __curunit, __filetype
+        .import         curunit, __filetype
         .importzp       ptr1, tmp1
 
         .include        "ctype.inc"
@@ -147,7 +147,7 @@ drivedone:
 
 .proc   fndefunit
 
-        lda     __curunit
+        lda     curunit
         sta     fnunit
         rts
 

libsrc/cbm/filevars.s

@@ -4,14 +4,14 @@
 ; Variables used for CBM file I/O
 ;
 
-        .export         __curunit
+        .export         curunit
         .constructor    initcurunit, 30
         .importzp       devnum
 
 
 .bss
 
-__curunit:
+curunit:
         .res    1
 
 
@@ -23,7 +23,7 @@ __curunit:
         bne     @L0
         lda     #8              ; Default is disk
         sta     devnum
-@L0:    sta     __curunit
+@L0:    sta     curunit
         rts
 
 .endproc

libsrc/cbm/initcwd.s

@@ -5,7 +5,7 @@
 ;
 
 	.export		initcwd, devicestr
-	.import		__curunit, __cwd
+	.import		curunit, __cwd
 	.import		pusha0, tosudiva0
 	.importzp	sreg, ptr1, ptr2
 
@@ -16,7 +16,7 @@ initcwd:
 	ldx	#>__cwd
 	sta	ptr2
 	stx	ptr2+1
-	lda	__curunit
+	lda	curunit
 	; Fall through
 
 ;------------------------------------------------------------------------------
@@ -28,11 +28,11 @@ devicestr:
 	jsr	tosudiva0
 	ldy	#0
 	lda	sreg
-	beq	:+		; >=10
+	beq	@L0		; >=10
 	add	#'0'
 	sta	(ptr2),y
 	iny
-:	lda	ptr1		; rem
+@L0:	lda	ptr1		; rem
 	add	#'0'
 	sta	(ptr2),y
 	iny

libsrc/cbm/syschdir.s

@@ -0,0 +1,86 @@
+;
+; Oliver Schmidt, 2012-10-16
+;
+; unsigned char __fastcall__ _syschdir (const char* name);
+;
+
+        .export         __syschdir
+        .import         curunit, initcwd
+        .importzp       ptr1, tmp1, tmp2
+
+;--------------------------------------------------------------------------
+; __syschdir
+
+.proc   __syschdir
+
+; Save name
+
+        sta     ptr1
+        stx     ptr1+1
+
+; Process first character
+
+        ldy     #0
+        lda     (ptr1),y
+        beq     err
+        jsr     getdigit
+        bcs     err
+        tax
+
+; Process second character
+
+        iny
+        lda     (ptr1),y
+        beq     done
+        jsr     getdigit
+        bcs     err
+        stx     tmp1            ; First digit
+        sta     tmp2            ; Second digit
+
+; Multiply first digit by 10
+
+        ldx     #8
+@L0:    asl
+        asl     tmp1
+        bcc     @L1
+        clc
+        adc     #10
+@L1:    dex
+        bne     @L0
+
+; Add second digit to product
+
+        clc
+        adc     tmp2
+        tax
+
+; Process third character
+
+        iny
+        lda     (ptr1),y
+        bne     err
+
+; Success, update cwd
+
+done:   stx     curunit
+        jmp     initcwd         ; Returns with A = 0
+
+err:    lda     #9              ; "Ilegal device"
+        rts
+
+.endproc
+
+;--------------------------------------------------------------------------
+; getdigit
+
+.proc   getdigit
+
+        sec
+        sbc     #'0'
+        bcs     @L0
+        sec
+        rts
+@L0:    cmp     #10
+        rts
+
+.endproc