Rewrote printf in assembler

git-svn-id: svn://svn.cc65.org/cc65/trunk@506 b7a2c559-68d2-44c3-8de9-860c34a00d81

libsrc/common/.cvsignore

@@ -26,7 +26,6 @@ getchar.s
 gets.s
 locale.s
 perror.s
-printf.s
 putchar.s
 puts.s
 qsort.s

libsrc/common/Makefile

@@ -13,7 +13,7 @@
 
 C_OBJS = fclose.o fgets.o fprintf.o calloc.o _fopen.o\
 	 fputs.o fread.o fwrite.o gets.o realloc.o bsearch.o strxfrm.o\
-	 printf.o _hextab.o vfprintf.o fdopen.o strtok.o\
+	 _hextab.o vfprintf.o fdopen.o strtok.o\
 	 _afailed.o fopen.o fgetc.o fputc.o puts.o gets.o perror.o getchar.o\
 	 vprintf.o vsprintf.o sprintf.o abort.o qsort.o putchar.o\
 	 errormsg.o cprintf.o vcprintf.o freopen.o locale.o fsetpos.o\
@@ -58,6 +58,7 @@ S_OBJS = 	_fdesc.o	\
 		memcmp.o    	\
 	 	memcpy.o    	\
 	 	memset.o    	\
+		printf.o	\
 	 	rand.o	    	\
 	 	setjmp.o    	\
 		stkcheck.o  	\

libsrc/common/printf.c

@@ -1,26 +0,0 @@
-/*
- * printf.c
- *
- * Ullrich von Bassewitz, 11.08.1998
- */
-
-
-
-#include <stdarg.h>
-#include <stdio.h>
-
-
-
-int printf (const char* format, ...)
-{
-    va_list ap;
-    va_start (ap, format);
-
-    /* Do formatting and output. Since we know, that va_end is empty, we don't
-     * call it here, saving an extra variable and some code.
-     */
-    return vfprintf (stdout, (char*) va_fix (ap, 1), ap);
-}
-
-
-

libsrc/common/printf.s

@@ -0,0 +1,77 @@
+;
+; int printf (const char* Format, ...);
+;
+; Ullrich von Bassewitz, 1.12.2000
+;
+
+	.export	      	_printf
+	.import		_stdout, pushax, addysp, _vfprintf
+	.importzp	sp, ptr1
+
+	.macpack	generic
+
+; ----------------------------------------------------------------------------
+; Data
+
+.bss
+
+ParamSize: 	.res  	1		; Number of parameter bytes
+
+; ----------------------------------------------------------------------------
+; Code
+
+.code
+
+
+_printf:
+  	sty	ParamSize		; Number of param bytes passed in Y
+
+; We are using a (hopefully) clever trick here to reduce code size. On entry,
+; the stack pointer points to the last pushed parameter	of the variable
+; parameter list. Adding the number of parameter bytes, would result in a
+; pointer that points *after* the Format parameter.
+; Since we have to push stdout anyway, we will do that here, so
+;
+;   * we will save the subtraction of 2 (__fixargs__) later
+;   * we will have the address of the Format parameter which needs to
+;     be pushed next.
+;
+
+	lda	_stdout
+	ldx	_stdout+1
+	jsr	pushax
+
+; Now calculate the va_list pointer, which does points to Format
+
+	lda	sp
+	ldx	sp+1
+	add	ParamSize
+	bcc	@L1
+	inx
+@L1:	sta	ptr1
+	stx	ptr1+1
+
+; Push Format
+
+	ldy	#1
+	lda	(ptr1),y
+	tax
+	dey
+	lda	(ptr1),y
+	jsr	pushax
+
+; Push the va_list
+
+	lda	ptr1
+	ldx	ptr1+1
+	jsr	pushax
+
+; Call vfprintf
+
+	jsr	_vfprintf	
+
+; Cleanup the stack. We will return what we got from vfprintf
+
+	ldy	ParamSize
+	jmp	addysp
+