Renamed oserrcheck to __mappederrno. Added an additional function named

__directerrno and moved both to errno.s. Changed several sources to use these
functions. Needs testing.
                         


git-svn-id: svn://svn.cc65.org/cc65/trunk@4718 b7a2c559-68d2-44c3-8de9-860c34a00d81

libsrc/common/errno.s

@@ -1,11 +1,45 @@
 ;
-; Ullrich von Bassewitz, 06.06.1998
+; Ullrich von Bassewitz, 2003-08-12
 ;
-; int _errno;
+; Helper functions for several high level file functions.
 ;
 
-      	.export		__errno
 
+        .include        "errno.inc"
+
+.code
+
+; ----------------------------------------------------------------------------
+; int __fastcall__ _directerrno (unsigned char code);
+; /* Set errno to a specific error code, clear _oserror and return -1. Used
+;  * by the library.
+;  */
+
+__directerrno:
+        jsr     __seterrno              ; Set errno, returns with A = 0
+        sta     __oserror               ; Clear __oserror
+        beq     fail                    ; Branch always
+
+; ----------------------------------------------------------------------------
+; int __fastcall__ _mappederrno (unsigned char code);
+; /* Set _oserror to the given platform specific error code. If it is a real
+;  * error code (not zero) set errno to the corresponding system error code
+;  * and return -1. Otherwise return zero.
+;  * Used by the library.
+;  */
+
+__mappederrno:
+        sta     __oserror               ; Store the error code
+        tax                             ; Did we have an error?
+        beq     ok                      ; Branch if no
+        jsr     __osmaperrno            ; Map os error into errno code
+        jsr     __seterrno              ; Save in errno
+fail:   lda     #$FF                    ; Return -1
+        tax
+ok:     rts
+
+
+; ----------------------------------------------------------------------------
 .bss
 
 __errno: