libfbx-memset.c

libfxb是linux下只写操作framebuffer的一个轻量级的库。

/*
 *  libfbx-memset.c -- Optimized memset() routines.
 *  (C)opyright 2000-2001 U4X Labs
 *
 *  Written by: Paul Mundt <[e-mail]>
 *              Sat Sep 30 04:42:23 EDT 2000
 *
 *  $Id: libfbx-memset.c,v 1.10 2001/02/11 06:00:31 lethal Exp $
 *
 *  	All architecture specific memset() routines are located
 *  here. As well as a general purpose 16bit if no architecture
 *  specific one is available.
 *
 *  See ChangeLog for modifications, CREDITS for credits.
 *
 *  All source herein is copyright U4X Labs and its original author. 
 *  Any code modifications or additions are (C)opyright the original 
 *  author and U4X Labs respectively.
 *
 *  libfbx is free software; you can redistribute it and/or modify it 
 *  under the terms of the GNU Lesser General Public License as 
 *  published by the Free Software Foundation; either version 2.1 of 
 *  the License, or (at your option) any later version.
 *
 *  libfbx 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 Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with libfbx; if not, write to the Free Software 
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
 *  USA
 */
#include <libfbx/libfbx-arch.h>
#include <linux/types.h>
#include <config.h>

#if defined(__mips__)
static inline void *fb_arch_memset(void *s, int c, size_t n)
{
	__asm__ __volatile__ (
		"la\t$8,%0\n\t"
		"lb\t$9,%1\n\t"
		"lb\t$10,%2\n\t"

		"loop:\n\t"
		"sb\t$9,0($8)\n\t"
		"add\t$8,$8,1\n\t"
		"sub\t$10,$10,1\n\t"
		"beqz\t$10,exit\n\t"
		"j\tloop\n\t"

		"exit:\n\t"
		:
		: "g" (s), "g" (c), "g" (n)
                : "$8", "$9", "$10", "memory"
	);
}
#elif defined(__i386__)
static inline void *fb_arch_memset(void *s, int c, size_t n)
{
	int d0, d1;

	__asm__ __volatile__(
		"cld\n\t"
		"rep ; stosl\n\t"
		"testb $2,%b3\n\t"
		"je 1f\n\t"
		"stosw\n"
		"1:\ttestb $1,%b3\n\t"
		"je 2f\n\t"
		"stosb\n"
		"2:"
		: "=&c" (d0), "=&D" (d1)
		: "a" (c), "q" (n), "0" (n/4), "1" ((long) s)
		: "memory"
	);
		
	return s;
}
#elif defined(__superh__)
static inline void *fb_arch_memset(void *s, int c, size_t n)
{
	__asm__ __volatile__ (
		"tst\tr6,r6\n"
		"bt/s\t5f\n"
	 	"add\tr6,r4\n"
		"mov\t#12,r0\n"
		"cmp/gt\tr6,r0\n"
		"bt/s\t4f\n"
	 	"mov\tr4,r0\n"
		"and\t#3,r0\n"
		"cmp/eq\t#0,r0\n"
		"bt/s\t2f\n"
		"sub\tr0,r6\n"
		"1:\n"
		"dt\tr0\n"
		"bf/s\t1b\n"
		"mov.b\tr5,@-r4\n"
		"2:\n"
		"swap.b\tr5,r0\n"
		"or\tr0,r5\n"
		"swap.w\tr5,r0\n"
		"or\tr0,r5\n"
		"mov\tr6,r0\n"
		"shlr2\tr0\n"
		"shlr\tr0\n"
		"3:\n"
		"dt\tr0\n"
		"mov.l\tr5,@-r4\n"
		"bf/s\t3b\n"
		"mov.l\tr5,@-r4\n"
		"mov\t#7,r0\n"
		"and\tr0,r6\n"
		"tst\tr6,r6\n"
		"bt\t5f\n"
		"4:\n"
		"dt\tr6\n"
		"bf/s\t4b\n"
	 	"mov.b\tr5,@-r4\n"
		"5:\n"
		"rts\n"
		"mov\tr4,r0\n"
		:
		: "a" (c), "q" (n), "0" (n/4), "1" ((long)s)
		: "memory"
	);

	return s;
}
#else
static inline void *fb_arch_memset(void *s, int c, size_t n)
{
  	while ((__u32)n--)
		*(__u16 *)s++ = (__u16)c;
	
	return s;
}
#endif

inline void *fb_memset(void *s, int c, size_t n)
{
	return fb_arch_memset(s, c, n);
}