[uClibc-cvs] uClibc/libc/string/powerpc Makefile, NONE, 1.1 string.c, NONE, 1.1

[Erik Andersen]

Update of /var/cvs/uClibc/libc/string/powerpc
In directory nail:/tmp/cvs-serv7570/powerpc

Added Files:
	Makefile string.c 
Log Message:
Joakim Tjernlund writes:

Hi Erik

I have had some fun trying to optimize memcpy, memset and memmove for
PPC. There are only boot tested, but  I don't expect any problems :)

Read the comments in powerpc/string.c for more info.
Patch is relative to libc/string

 Jocke



--- NEW FILE: Makefile ---
# Makefile for uClibc
#
# Copyright (C) 2000-2003 Erik Andersen <andersen at uclibc.org>
#
# This program is free software; you can redistribute it and/or modify it under
# the terms of the GNU Library General Public License as published by the Free
# Software Foundation; either version 2 of the License, or (at your option) any
# later version.
#
# This program is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE. See the GNU Library General Public License for more
# details.
#
# You should have received a copy of the GNU Library General Public License
# along with this program; if not, write to the Free Software Foundation, Inc.,
# 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

TOPDIR=../../../
include $(TOPDIR)Rules.mak

MSRC= string.c
MOBJ= memcpy.o memmove.o memset.o bzero.o 
OBJS=$(MOBJ)

all: $(OBJS) $(LIBC)

$(LIBC): ar-target

ar-target: $(OBJS)
	$(AR) $(ARFLAGS) $(LIBC) $(OBJS)

$(MOBJ): $(MSRC)
	$(CC) $(CFLAGS) -DL_$* $< -c -o $*.o
	$(STRIPTOOL) -x -R .note -R .comment $*.o

$(COBJS): %.o : %.c
	$(CC) $(CFLAGS) -c $< -o $@
	$(STRIPTOOL) -x -R .note -R .comment $*.o

clean:
	$(RM) *.[oa] *~ core


--- NEW FILE: string.c ---
/*
 * This program is free software; you can redistribute it and/or modify it under
 * the terms of the GNU Library General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option) any
 * later version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE. See the GNU Library General Public License for more
 * details.
 */

/* These are carefully optimized mem*() functions for PPC written in C.
 * Don't muck around with these function without checking the generated
 * assmbler code.
 * It is possible to optimize these significantly more by using specific
 * data cache instructions(mainly dcbz). However that requires knownledge
 * about the CPU's cache line size.
 *
 * BUG ALERT!
 * The cache instructions on MPC8xx CPU's are buggy(they don't update
 * the DAR register when causing a DTLB Miss/Error) and cannot be
 * used on 8xx CPU's without a kernel patch to work around this
 * problem.
 *   
 * Copyright (C) 2004 Joakim Tjernlund
 */

#define _STDIO_UTILITY
#define _GNU_SOURCE
#include <string.h>
#include <locale.h> /* for __LOCALE_C_ONLY */

#ifdef L_memcpy
void *memcpy(void *to, const void *from, size_t n)
/* PPC can do pre increment and load/store, but not post increment and load/store.
   Therefore use *++ptr instead of *ptr++. */
{
	unsigned long rem, chunks, tmp1, tmp2;
	void *tmp_to;

	chunks = n / 8;
	from -= 4;
	tmp_to = to - 4;
	if (!chunks)
		goto lessthan8;
	rem = (unsigned long )tmp_to % 4;
	if (rem)
		goto align;
 copy_chunks:
	do {
		/* make gcc to load all data, then store it */
		tmp1 = *(unsigned long *)(from+4);
		from += 8;
		tmp2 = *(unsigned long *)from;
		*(unsigned long *)(tmp_to+4) = tmp1;
		tmp_to += 8;
		*(unsigned long *)tmp_to = tmp2;
	} while (--chunks);
 lessthan8:
	n = n % 8;
	if (n >= 4) {
		*++(unsigned long *)tmp_to = *++(unsigned long *)from;
		n = n-4;
	}
	if (!n ) return to;
	from += 3;
	tmp_to += 3;
	do {
		*++(unsigned char *)tmp_to = *++(unsigned char *)from;
	} while (--n);
	
	return to;
 align:
	rem = 4 - rem;
	n = n-rem;
	do {
		*(unsigned char *)(tmp_to+4) = *(unsigned char *)(from+4);
		++from;
		++tmp_to;
	} while (--rem);
	chunks = n / 8;
	if (chunks)
		goto copy_chunks;
	goto lessthan8;
}
#endif

#ifdef L_memmove
void *memmove(void *to, const void *from, size_t n)
{
	unsigned long rem, chunks, tmp1, tmp2;
	void *tmp_to;

	if (from >= to)
		return memcpy(to, from, n);
	chunks = n / 8;
	from += n;
	tmp_to = to + n;
	if (!chunks)
		goto lessthan8;
	rem = (unsigned long )tmp_to % 4;
	if (rem)
		goto align;
 copy_chunks:
	do {
		/* make gcc to load all data, then store it */
		tmp1 = *(unsigned long *)(from-4);
		from -= 8;
		tmp2 = *(unsigned long *)from;
		*(unsigned long *)(tmp_to-4) = tmp1;
		tmp_to -= 8;
		*(unsigned long *)tmp_to = tmp2;
	} while (--chunks);
 lessthan8:
	n = n % 8;
	if (n >= 4) {
		*--(unsigned long *)tmp_to = *--(unsigned long *)from;
		n = n-4;
	}
	if (!n ) return to;
	do {
		*--(unsigned char *)tmp_to = *--(unsigned char *)from;
	} while (--n);
	
	return to;
 align:
	rem = 4 - rem;
	n = n-rem;
	do {
		*--(unsigned char *)tmp_to = *--(unsigned char *)from;
	} while (--rem);
	chunks = n / 8;
	if (chunks)
		goto copy_chunks;
	goto lessthan8;
}
#endif

#ifdef L_memset
static inline int expand_byte_word(int c){
	/* this does: 
	   c = c << 8 | c;
	   c = c << 16 | c ;
	*/
	asm("rlwimi	%0,%0,8,16,23\n"
	    "\trlwimi	%0,%0,16,0,15\n"
	    : "=r" (c) : "0" (c));
	return c;
}
void *memset(void *to, int c, size_t n)
{
	unsigned long rem, chunks;
	void *tmp_to;

	chunks = n / 8;
	tmp_to = to - 4;
	c = expand_byte_word(c);
	if (!chunks)
		goto lessthan8;
	rem = (unsigned long )tmp_to % 4;
	if (rem)
		goto align;
 copy_chunks:
	do {
		*++(unsigned long *)tmp_to = c;
		*++(unsigned long *)tmp_to = c;
	} while (--chunks);
 lessthan8:
	n = n % 8;
	if (n >= 4) {
		*++(unsigned long *)tmp_to = c;
		n = n-4;
	}
	if (!n ) return to;
	tmp_to += 3;
	do {
		*++(unsigned char *)tmp_to = c;
	} while (--n);
	
	return to;
 align:
	rem = 4 - rem;
	n = n-rem;
	do {
		*(unsigned char *)(tmp_to+4) = c;
		++tmp_to;
	} while (--rem);
	chunks = n / 8;
	if (chunks)
		goto copy_chunks;
	goto lessthan8;
}
#endif

#ifdef L_bzero
void bzero(void *s, size_t n)
{
	(void)memset(s, 0, n);
}
#endif