From e4d9fd3bd17dfc57ad8d17852d4c1cd75abd15a3 Mon Sep 17 00:00:00 2001
From: uz <uz@b7a2c559-68d2-44c3-8de9-860c34a00d81>
Date: Mon, 28 Sep 2009 18:39:55 +0000
Subject: [PATCH] Fixed more bugs, shortened the code where possible.

git-svn-id: svn://svn.cc65.org/cc65/trunk@4257 b7a2c559-68d2-44c3-8de9-860c34a00d81
---
 libsrc/common/vsnprintf.s | 171 ++++++++++++++++++++------------------
 libsrc/common/vsprintf.s  |  14 ++--
 2 files changed, 98 insertions(+), 87 deletions(-)

diff --git a/libsrc/common/vsnprintf.s b/libsrc/common/vsnprintf.s
index 10dc7fa1d..21c358780 100644
--- a/libsrc/common/vsnprintf.s
+++ b/libsrc/common/vsnprintf.s
@@ -4,7 +4,7 @@
 ; Ullrich von Bassewitz, 2009-09-26
 ;
 
-   	.export	      	_vsnprintf
+   	.export	      	_vsnprintf, vsnprintf
  	.import	      	ldaxysp, popax, incsp2, incsp6
 	.import	      	_memcpy, __printf
 	.importzp     	sp, ptr1
@@ -26,75 +26,6 @@ bufsize:.word   0               ; Buffer size
 
 .code
 
-; ----------------------------------------------------------------------------
-; Callback routine used for the actual output.
-;
-; static void out (struct outdesc* d, const char* buf, unsigned count)
-; /* Routine used for writing */
-;
-; Since we know, we're called with a pointer to our static outdesc structure,
-; we don't need the pointer passed on the stack.
-
-out:
-
-; Calculate the space left in the buffer. If no space is left, don't copy
-; any characters
-
-        lda     bufsize                 ; Low byte of buffer size
-        sec
-        sbc     ccount+0                ; Low byte of bytes already written
-        sta     ptr1
-        lda     bufsize+1
-        sbc     ccount+1
-        sta     ptr1+1
-        bcs     @L0                     ; Space left
-        lda     #0
-        sta     ptr1
-        sta     ptr1+1
-
-; Replace the pointer to d by a pointer to the write position in the buffer
-; for the call to memcpy that follows.
-
-@L0:    lda     bufptr+0
-        clc
-        adc     ccount+0
-        ldy     #4
-        sta     (sp),y
-
-        lda     bufptr+1
-        adc     ccount+1
-        iny
-        sta     (sp),y
-
-; Get Count from stack
-
-        jsr     popax
-
-; outdesc.ccount += Count;
-
-        pha
-        clc
-        adc     ccount+0
-        sta     ccount+0
-        txa
-        adc     ccount+1
-        sta     ccount+1
-        pla
-
-; if (Count > Left) Count = Left;
-
-        cpx     ptr1+1
-        bne     @L1
-        cmp     ptr1
-@L1:    bcc     @L2
-        lda     ptr1
-        ldx     ptr1+1
-
-; Jump to memcpy, which will cleanup the stack and return to the caller
-
-@L2:    jmp     _memcpy
-
-
 ; ----------------------------------------------------------------------------
 ; vsprintf - formatted output into a buffer
 ;
@@ -102,10 +33,14 @@ out:
 ;
 
 _vsnprintf:
-    	pha	   		; Save low byte of ap
+    	pha	   		; Save ap
+        txa
+        pha
 
-; Setup the outdesc structure
+; Setup the outdesc structure. This is also an additional entry point for
+; vsprintf with ap on stack
 
+vsnprintf:
     	lda	#0
     	sta	ccount+0
     	sta	ccount+1        ; Clear ccount
@@ -117,11 +52,14 @@ _vsnprintf:
         ldy     #2
         lda     (sp),y
         sta     ptr1
+
         lda     #<outdesc
         sta     (sp),y
+
         iny
         lda     (sp),y
         sta     ptr1+1
+
         ora     ptr1
         beq     L9
 
@@ -130,12 +68,12 @@ _vsnprintf:
 
 ; Write size-1 to outdesc.uns
 
-        ldx     ptr1
         ldy     ptr1+1
-        dex
+        ldx     ptr1
         bne     L1
         dey
-L1:     stx     bufsize+0
+L1:     dex
+        stx     bufsize+0
         sty     bufsize+1
 
 ; Copy buf to the outdesc.ptr
@@ -145,12 +83,15 @@ L1:     stx     bufsize+0
         sta     bufptr+0
         stx     bufptr+1
 
-; Restore low byte of ap and call _printf
+; Restore ap and call _printf
 
 	pla
+        tax
+        pla
 	jsr	__printf
 
-; Terminate the string
+; Terminate the string. The last char is either at bufptr+ccount or
+; bufptr+bufsize, whichever is smaller.
 
         lda     ccount+0
         ldx     ccount+1
@@ -177,10 +118,82 @@ L3:     adc     bufptr+0
         ldx     ccount+1
 	jmp     incsp2
 
-; Bail out if size is zero
+; Bail out if size is zero.
 
-L9:     lda     #0
+L9:     pla
+        pla                     ; Discard ap
+        lda     #0
         tax
         jmp     incsp6          ; Drop parameters
 
 
+; ----------------------------------------------------------------------------
+; Callback routine used for the actual output.
+;
+; static void out (struct outdesc* d, const char* buf, unsigned count)
+; /* Routine used for writing */
+;
+; Since we know, we're called with a pointer to our static outdesc structure,
+; we don't need the pointer passed on the stack.
+
+out:
+
+; Calculate the space left in the buffer. If no space is left, don't copy
+; any characters
+
+        lda     bufsize+0               ; Low byte of buffer size
+        sec
+        sbc     ccount+0                ; Low byte of bytes already written
+        sta     ptr1
+        lda     bufsize+1
+        sbc     ccount+1
+        sta     ptr1+1
+        bcs     @L0                     ; Branch if space left
+        lda     #$00
+        sta     ptr1
+        sta     ptr1+1                  ; No space left
+
+; Replace the pointer to d by a pointer to the write position in the buffer
+; for the call to memcpy that follows.
+
+@L0:    lda     bufptr+0
+        clc
+        adc     ccount+0
+        ldy     #4
+        sta     (sp),y
+
+        lda     bufptr+1
+        adc     ccount+1
+        iny
+        sta     (sp),y
+
+; Get Count from stack
+
+        jsr     popax
+
+; outdesc.ccount += Count;
+
+        pha
+        clc
+        adc     ccount+0
+        sta     ccount+0
+        txa
+        adc     ccount+1
+        sta     ccount+1
+        pla
+
+; if (Count > Left) Count = Left;
+
+        cpx     ptr1+1
+        bne     @L1
+        cmp     ptr1
+@L1:    bcc     @L2
+        lda     ptr1
+        ldx     ptr1+1
+
+; Jump to memcpy, which will cleanup the stack and return to the caller
+
+@L2:    jmp     _memcpy
+
+
+
diff --git a/libsrc/common/vsprintf.s b/libsrc/common/vsprintf.s
index 4c265ec22..f1a2fe5d8 100644
--- a/libsrc/common/vsprintf.s
+++ b/libsrc/common/vsprintf.s
@@ -4,9 +4,9 @@
 ; Ullrich von Bassewitz, 2009-09-26
 ;
 
-   	.export	      	_vsprintf
-	.import	      	pushw0sp, staxysp
-	.import	      	_vsnprintf
+   	.export	       	_vsprintf
+	.import	       	pushw0sp, staxysp
+	.import	       	vsnprintf
 
 
 ; ----------------------------------------------------------------------------
@@ -30,10 +30,8 @@ _vsprintf:
         ldy     #2
         jsr     staxysp
 
-; Retrieve ap and contine by jumping to _vsnprintf, which will cleanup the stack
+; Contine by jumping to vsnprintf, which expects ap on the CPU stack and will 
+; cleanup the C stack
 
-        pla
-        tax
-        pla
-        jmp     _vsnprintf
+        jmp     vsnprintf
 
-- 
2.39.5