From 100fbfc0d1ddae8ce4dca068b149167e1032f2d1 Mon Sep 17 00:00:00 2001
From: cuz <cuz@b7a2c559-68d2-44c3-8de9-860c34a00d81>
Date: Mon, 14 Feb 2005 09:59:54 +0000
Subject: [PATCH] Fixed a bug (report and patch by Greg King)

git-svn-id: svn://svn.cc65.org/cc65/trunk@3384 b7a2c559-68d2-44c3-8de9-860c34a00d81
---
 libsrc/common/vfprintf.s | 129 ++++++++++++++++++++-------------------
 1 file changed, 66 insertions(+), 63 deletions(-)

diff --git a/libsrc/common/vfprintf.s b/libsrc/common/vfprintf.s
index 21f4ff33b..c839c2c02 100644
--- a/libsrc/common/vfprintf.s
+++ b/libsrc/common/vfprintf.s
@@ -1,29 +1,28 @@
+; vfprintf.s
 ;
-; int vfprintf (FILE* f, const char* Format, va_list ap);
-;
-; Ullrich von Bassewitz, 1.12.2000
+; int fastcall vfprintf(FILE* f, const char* Format, va_list ap);
 ;
+; 2005-02-08, Ullrich von Bassewitz
+; 2005-02-11, Greg King
 
-	.export	      	_vfprintf
-	.import	       	pushax, popax, push1, pushwysp, ldaxysp, ldaxidx, incsp6
-	.import	       	_fwrite, __printf
-	.importzp      	sp, ptr1, ptr2
+        .export	      	_vfprintf
+        .import	       	pushax, popax, push1, pushwysp, ldaxysp, ldaxidx, incsp6
+        .import	       	_fwrite, __printf
+        .importzp      	sp, ptr1, ptr2
 
-	.macpack      	generic
+        .macpack      	generic
 
 
 .data
 
 ; ----------------------------------------------------------------------------
-;
 ; Static data for the _vfprintf routine
 ;
-
-outdesc:			; Static outdesc structure
-	.word	0		; ccount
-	.word	out		; Output function pointer
-	.word	0		; ptr
-	.word	0		; uns
+outdesc:                        ; Static outdesc structure
+ccount: .res	2
+        .word	out		; Output function pointer
+ptr:    .res	2		; Points to output file
+        .res	2		; (Not used by this function)
 
 .code
 
@@ -33,24 +32,20 @@ outdesc:			; Static outdesc structure
 ; static void out (struct outdesc* d, const char* buf, unsigned count)
 ; /* Routine used for writing */
 ; {
+;     register size_t cnt;
 ;     /* Write to the file */
-;     if (fwrite (buf, count, 1, (FILE*) d->ptr) == -1) {
+;     if ((cnt = fwrite(buf, 1, count, (FILE *)d->ptr)) == 0) {
 ;         d->ccount = -1;
 ;     } else {
-;         d->ccount += count;
+;         d->ccount += cnt;
 ;     }
 ; }
 
-out:
-
 ; About to call
 ;
-;      	fwrite (buf, 1, count, (FILE*) d->ptr);
+;       fwrite (buf, 1, count, (FILE*) d->ptr);
 ;
-; Since Buf and Count are already in place, we will just push the last
-; two parameters. The fwrite function will remove Buf and Count on exit.
-
-        ldy     #5
+out:    ldy     #5
         jsr     pushwysp        ; Push buf
         jsr     push1           ; Push #1
         ldy     #7
@@ -59,9 +54,9 @@ out:
         jsr     ldaxysp         ; Load D
         ldy     #5              ; Offset of ptr1+1 in struct outdesc
         jsr     ldaxidx         ; Load
-  	jsr	_fwrite
-       	sta	ptr2 		; Save function result
-	stx	ptr2+1
+        jsr	_fwrite
+        sta	ptr2 		; Save function result
+        stx	ptr2+1
 
 ; Get D and store it in ptr1
 
@@ -72,41 +67,49 @@ out:
 
 ; Load the offset of ccount in struct outdesc
 
-	ldy	#$00
+        ldy	#$00
 
-; Check the return code. Checking the high byte against $FF is ok here.
+; Check the return value.
 
-       	lda	ptr2+1
- 	cmp	#$FF
-	bne	@Ok
+        lda	ptr2+1
+        ora	ptr2
+        bne	@Ok
 
 ; We had an error. Store -1 into d->ccount
 
-	sta	(ptr1),y
+.ifp02
+        lda	#<-1
+.else
+        dec	a
+.endif
+        sta	(ptr1),y
         iny
         bne     @Done           ; Branch always
 
 ; Result was ok, count bytes written
 
-@Ok:	lda	(ptr1),y
-	add	ptr2
-	sta	(ptr1),y
+@Ok:    lda	(ptr1),y
+        add	ptr2
+        sta	(ptr1),y
         iny
-	lda	(ptr1),y
-	adc	ptr2+1
-@Done:  sta	(ptr1),y
-	jmp     incsp6          ; Drop stackframe
+        lda	(ptr1),y
+        adc	ptr2+1
+@Done:  sta     (ptr1),y
+        jmp     incsp6          ; Drop stackframe
 
 
 ; ----------------------------------------------------------------------------
 ; vfprintf - formatted output
 ;
-; int vfprintf (FILE* f, const char* format, va_list ap)
+; int fastcall vfprintf(FILE* f, const char* format, va_list ap)
 ; {
-;     struct outdesc d;
+;     static struct outdesc d = {
+;         0,
+;         out
+;     };
 ;
 ;     /* Setup descriptor */
-;     d.fout = out;
+;     d.ccount = 0;
 ;     d.ptr  = f;
 ;
 ;     /* Do formatting and output */
@@ -115,39 +118,39 @@ out:
 ;     /* Return bytes written */
 ;     return d.ccount;
 ; }
-
+;
 _vfprintf:
-	pha			; Save low byte of ap
+        pha			; Save low byte of ap
 
 ; Setup the outdesc structure
 
-	lda	#0
-	sta	outdesc
-	sta	outdesc+1	; Clear ccount
+        lda	#0
+        sta	ccount
+        sta	ccount+1	; Clear character-count
 
 ; Reorder the stack. Replace f on the stack by &d, so the stack frame is
 ; exactly as _printf expects it. Parameters will get dropped by _printf.
 
-	ldy	#2		;
-	lda	(sp),y		; Low byte of f
-	sta	outdesc+4	;
-	lda	#<outdesc
-	sta	(sp),y
-	iny
-	lda	(sp),y	 	; High byte of f
-	sta	outdesc+5
-	lda	#>outdesc
-	sta	(sp),y
+        ldy	#2
+        lda	(sp),y		; Low byte of f
+        sta	ptr
+        lda	#<outdesc
+        sta	(sp),y
+        iny
+        lda	(sp),y	 	; High byte of f
+        sta	ptr+1
+        lda	#>outdesc
+        sta	(sp),y
 
 ; Restore low byte of ap and call _printf
 
-	pla
-	jsr	__printf
+        pla
+        jsr	__printf
 
 ; Return the number of bytes written
 
-	lda	outdesc
-	ldx	outdesc+1
-	rts
+        lda	ccount
+        ldx	ccount+1
+        rts