New stuff contributed by Oliver Schmidt

git-svn-id: svn://svn.cc65.org/cc65/trunk@3608 b7a2c559-68d2-44c3-8de9-860c34a00d81

libsrc/apple2/syschdir.s

@@ -0,0 +1,41 @@
+;
+; Oliver Schmidt, 17.04.2005
+;
+; unsigned char __fastcall__ _syschdir (const char* name);
+;
+
+        .export         __syschdir
+        .import		pushname, popname
+	.import		__cwd
+
+	.include	"zeropage.inc"
+	.include	"mli.inc"
+
+__syschdir:
+        ; Push name
+        jsr	pushname
+        bne	oserr
+
+        ; Set pushed name
+        lda	sp
+        ldx	sp+1
+        sta	mliparam + MLI::PREFIX::PATHNAME
+        stx	mliparam + MLI::PREFIX::PATHNAME+1
+
+        ; Change directory
+        lda	#SET_PREFIX_CALL
+        ldx	#PREFIX_COUNT
+        jsr	callmli
+	bcs	cleanup
+
+	ldy	#$01
+:	lda	(sp),y
+	sta	__cwd-1,y
+	beq	cleanup
+	iny
+	bne	:-		; Branch always
+
+        ; Cleanup name
+cleanup:jsr	popname		; Preserves A
+
+oserr:	rts