move fdtoiocb function into its own file -- idea by Daniel Serpell

git-svn-id: svn://svn.cc65.org/cc65/trunk@4478 b7a2c559-68d2-44c3-8de9-860c34a00d81

libsrc/atari/Makefile

@@ -78,6 +78,7 @@ OBJS = 	_scrsize.o      \
 	diowritev.o     \
 	dosdetect.o     \
 	fdtable.o       \
+	fdtoiocb.o      \
 	getargs.o       \
 	getdefdev.o     \
 	getfd.o         \

libsrc/atari/fdtable.s

@@ -10,7 +10,6 @@
 	.import fd_table,fd_index
 	.import fdt_to_fdi
 	.export	clriocb
-	.export	fdtoiocb
 	.export	fdtoiocb_down
 	.export	findfreeiocb
 	.export	fddecusage
@@ -88,31 +87,6 @@ loop:	sta	ICHID,x
 .endproc
 
 
-; gets fd in ax
-; return iocb index in A, fd_table index in X
-; return N bit set for invalid fd
-; all registers destroyed
-.proc	fdtoiocb
-
-	cpx	#0
-	bne	inval
-	cmp	#MAX_FD_INDEX
-	bcs	inval
-	tax
-	lda	fd_index,x
-	asl	a			; create index into fd table
-	asl	a
-	tax
-	lda	#$ff
-	cmp	fd_table+ft_iocb,x	; entry in use?
-	beq	inval			; no, return error
-	lda	fd_table+ft_usa,x	; get usage counter
-	beq	inval			; 0? should not happen
-	lda	fd_table+ft_iocb,x	; get iocb
-	rts
-
-.endproc	; fdtoiocb
-
 ; find a free iocb
 ; no entry parameters
 ; return ZF = 0/1 for not found/found
@@ -137,6 +111,7 @@ found:	rts
 
 .endproc	; findfreeiocb
 
+
 ; decrements usage counter for fd
 ; if 0 reached, it's marked as unused
 ; get fd index in tmp2
@@ -170,6 +145,7 @@ ret:	rts
 
 .endproc	; fddecusage
 
+
 ; newfd
 ;
 ; called from open() function

libsrc/atari/fdtoiocb.s

@@ -0,0 +1,41 @@
+;
+; Christian Groessler, May-2000
+; Moved from fdtable.s to it's own file by Daniel Serpell, 2009.
+;
+; Convert file descriptor to IOCB number
+;
+
+	.include "atari.inc"
+	.include "fd.inc"
+	.import fd_table,fd_index
+	.export	fdtoiocb
+
+	.code
+
+; gets fd in ax
+; return iocb index in A, fd_table index in X
+; return N bit set for invalid fd
+; all registers destroyed
+.proc	fdtoiocb
+
+	cpx	#0
+	bne	inval
+	cmp	#MAX_FD_INDEX
+	bcs	inval
+	tax
+	lda	fd_index,x
+	asl	a			; create index into fd table
+	asl	a
+	tax
+	lda	#$ff
+	cmp	fd_table+ft_iocb,x	; entry in use?
+	beq	inval			; no, return error
+	lda	fd_table+ft_usa,x	; get usage counter
+	beq	inval			; 0? should not happen
+	lda	fd_table+ft_iocb,x	; get iocb
+	rts
+
+inval:	ldx     #$ff			; sets N
+	rts
+
+.endproc	; fdtoiocb