From 35b7d549f4b2312496ad9a529d4812a84646a76f Mon Sep 17 00:00:00 2001
From: cuz <cuz@b7a2c559-68d2-44c3-8de9-860c34a00d81>
Date: Sat, 27 Nov 2004 14:56:54 +0000
Subject: [PATCH] Replace vfscanf by an assembler version

git-svn-id: svn://svn.cc65.org/cc65/trunk@3305 b7a2c559-68d2-44c3-8de9-860c34a00d81
---
 libsrc/common/.cvsignore |  1 -
 libsrc/common/Makefile   |  2 +-
 libsrc/common/_scanf.inc |  2 +-
 libsrc/common/vfscanf.c  | 39 ----------------------
 libsrc/common/vfscanf.s  | 70 ++++++++++++++++++++++++++++++++++++++++
 5 files changed, 72 insertions(+), 42 deletions(-)
 delete mode 100644 libsrc/common/vfscanf.c
 create mode 100644 libsrc/common/vfscanf.s

diff --git a/libsrc/common/.cvsignore b/libsrc/common/.cvsignore
index e96db4c09..d8d6186b3 100644
--- a/libsrc/common/.cvsignore
+++ b/libsrc/common/.cvsignore
@@ -37,7 +37,6 @@ strtok.s
 strxfrm.s
 system.s
 timezone.s
-vfscanf.s
 vscanf.s
 vsscanf.s
 
diff --git a/libsrc/common/Makefile b/libsrc/common/Makefile
index f9eea8104..43b56ba1c 100644
--- a/libsrc/common/Makefile
+++ b/libsrc/common/Makefile
@@ -67,7 +67,6 @@ C_OBJS =	_afailed.o	\
 		strtok.o	\
                 system.o        \
                 timezone.o      \
-                vfscanf.o       \
                 vscanf.o        \
                 vsscanf.o
 
@@ -169,6 +168,7 @@ S_OBJS = 	_cwd.o          \
                 unlink.o        \
                 utscopy.o       \
 		vfprintf.o	\
+                vfscanf.o       \
 		vprintf.o       \
 		vsprintf.o	\
 		zerobss.o
diff --git a/libsrc/common/_scanf.inc b/libsrc/common/_scanf.inc
index 48ae5b08a..91be888a6 100644
--- a/libsrc/common/_scanf.inc
+++ b/libsrc/common/_scanf.inc
@@ -14,7 +14,7 @@
 ;----------------------------------------------------------------------------
 ; Global data
 
-.global _scanf
+.global __scanf
 
 
 
diff --git a/libsrc/common/vfscanf.c b/libsrc/common/vfscanf.c
deleted file mode 100644
index 0f62113f7..000000000
--- a/libsrc/common/vfscanf.c
+++ /dev/null
@@ -1,39 +0,0 @@
-/*
- * vfscanf.c
- *
- * Ullrich von Bassewitz (uz@cc65.org), 2004-11-26
- *
- */
-
-
-
-#include <stdio.h>
-#include "_scanf.h"
-
-
-
-/*****************************************************************************/
-/*     	    	     		     Code				     */
-/*****************************************************************************/
-
-
-
-int __fastcall__ vfscanf (FILE* f, const char* format, va_list ap)
-/* Standard C function */
-{
-    struct scanfdata d;
-
-    /* Initialize the data struct. We do only need the given file as user data,
-     * since the get and ungetc are crafted so they match the standard fgetc
-     * and ungetc functions.
-     */
-    d.get    = (getfunc) fgetc,
-    d.unget  = (ungetfunc) ungetc,
-    d.data   = f;
-
-    /* Call the internal function and return the result */
-    return _scanf (&d, format, ap);
-}
-
-
-
diff --git a/libsrc/common/vfscanf.s b/libsrc/common/vfscanf.s
new file mode 100644
index 000000000..057a62cc3
--- /dev/null
+++ b/libsrc/common/vfscanf.s
@@ -0,0 +1,70 @@
+;
+; int __fastcall__ vfscanf (FILE* f, const char* format, va_list ap);
+;
+; Ullrich von Bassewitz, 2004-11-27
+;
+
+  	.export	      	_vfscanf
+        .import         _fgetc, _ungetc
+
+        .include        "zeropage.inc"
+        .include        "_scanf.inc"
+
+
+; ----------------------------------------------------------------------------
+; Static scanfdata structure for the _vfscanf routine
+;
+
+.data
+d:      .addr   _fgetc          ; GET
+	.addr   _ungetc         ; UNGET
+       	.addr   0               ; data
+
+
+; ----------------------------------------------------------------------------
+; int __fastcall__ vfscanf (FILE* f, const char* format, va_list ap)
+; /* Standard C function */
+; {
+;     struct scanfdata d;
+;
+;     /* Initialize the data struct. We do only need the given file as user data,
+;      * since the get and ungetc are crafted so they match the standard fgetc
+;      * and ungetc functions.
+;      */
+;     d.get    = (getfunc) fgetc,
+;     d.unget  = (ungetfunc) ungetc,
+;     d.data   = f;
+;
+;     /* Call the internal function and return the result */
+;     return _scanf (&d, format, ap);
+; }
+;
+; Since _scanf has the same parameter stack as vfscanf, with f replaced by &d,
+; we will do exactly that. _scanf will then clean up the stack, so we can jump
+; directly there, no need to return.
+; Beware: Since ap is a fastcall parameter, we must not destroy a/x.
+;
+
+.code
+_vfscanf:
+        pha                     ; Save low byte of ap
+
+; Swap f against &d on the stack, placing f into d.data
+
+        ldy     #2              ; Offset of f on the stack
+        lda     (sp),y
+        sta     d + SCANFDATA::DATA
+        lda     #<d
+        sta     (sp),y
+
+        iny                     ; High byte
+        lda     (sp),y
+        sta     d + SCANFDATA::DATA + 1
+        lda     #>d
+        sta     (sp),y
+
+; Restore the low byte of ap and jump to the _scanf function
+
+        pla
+        jmp     __scanf
+
-- 
2.39.5