minix/common/lib/libc/arch/mips/gen/byte_swap_8.S
Gianluca Guida b6cbf7203b Import unmodified NetBSD libc in trunk
This patch imports the unmodified current version of NetBSD libc.
The NetBSD includes are in /nbsd_include, while the libc code itself is 
split between lib/nbsd_libc and common/lib/libc.
2011-02-14 19:36:03 +00:00

118 lines
4.5 KiB
ArmAsm

/* $NetBSD: byte_swap_8.S,v 1.2 2009/12/14 00:39:00 matt Exp $ */
/*-
* Copyright (c) 1991, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Ralph Campbell.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <mips/asm.h>
#if defined(LIBC_SCCS) && !defined(lint)
RCSID("$NetBSD: byte_swap_8.S,v 1.2 2009/12/14 00:39:00 matt Exp $")
#endif /* LIBC_SCCS and not lint */
#undef _LOCORE
#define _LOCORE /* XXX not really, just assembly-code source */
#include <machine/endian.h>
NLEAF(bswap64) # a0 = 0xffeeddccbbaa9988 return 0x8899aabbccddeeff
#if (__mips == 32 || __mips == 64) && __mips_isa_rev == 2
#if !defined(__mips_o32)
/*
* If we are on MIPS32r2 or MIPS64r2 use the new instructions.
*/
dsbh v0, a0 # dwords swap bytes within halfwords
dshd v0, v0 # dwords swap halwords within dwords
j ra
#else /* defined(__mips_o32) */
/*
* If we are on MIPS32r2 or MIPS64r2 use the new instructions.
* (except we must use the 32bit versions)
*/
wsbh v1, a0 # word swap bytes within halfwords
wsbh v0, a1 # word swap bytes within halfwords
rotr v1, v1, 16 # rotate word 16bits and swap word
rotr v0, v0, 16 # rotate word 16bits and swap word
j ra
#endif /* defined(__mips_o32) */
#elif !defined(__mips_o32)
# a0 = 0xffeeddccbbaa9988
li t0, 0xffff # t0 = 0x000000000000ffff
dsll t1, t0, 32 # t1 = 0x0000ffff00000000
or t0, t1 # t0 = 0x0000ffff0000ffff
dsll t2, t0, 8 # t2 = 0x00ffff0000ffff00
xor t2, t0 # t2 = 0x00ff00ff00ff00ff
/*
* We could swap by halfword, but that would be one instruction longer.
*/
dsrl ta0, a0, 32 # ta0 = 0x00000000ffeeddcc
dsll ta1, a0, 32 # ta1 = 0xbbaa998800000000
or a1, ta0, ta1 # a1 = 0xbbaa9988ffeeddcc
# words swapped
and ta0, a1, t0 # ta0 = 0x000099880000ddcc
dsrl ta1, a1, 16 # ta1 = 0x0000bbaa9988ffee
and ta1, t0 # ta1 = 0x0000bbaa0000ffee
dsll a2, ta0, 16 # a2 = 0x99880000ddcc0000
or a2, ta1 # a2 = 0x9988bbaaddccffee
# halfwords swapped
and ta0, a2, t2 # ta0 = 0x008800aa00cc00ee
dsrl ta1, a2, 8 # ta1 = 0x009988bbaaddccff
and ta1, t2 # ta1 = 0x009900bb00dd00ff
dsll v0, ta0, 8 # v0 = 0x8800aa00cc00ee00
or v0, ta1 # v0 = 0x8899aabbccddeeff
# bytes swapped
j ra
#else /* defined(__mips_o32) */
/*
* 32bit ABI.
*/
# a0 = 0xccddeeff
# a1 = 0x8899aabb
srl t0, a0, 24 # t0 = 0x000000cc
srl t1, a1, 24 # t1 = 0x00000088
sll ta0, a0, 24 # ta0 = 0xff000000
sll ta1, a1, 24 # ta1 = 0xbb000000
or ta0, ta0, t0 # ta0 = 0xff0000cc
or ta1, ta1, t1 # ta1 = 0xbb000088
and t0, a0, 0xff00 # t0 = 0x0000ee00
and t1, a1, 0xff00 # t1 = 0x0000aa00
sll t0, t0, 8 # t0 = 0x00ee0000
sll t1, t1, 8 # t1 = 0x00aa0000
or ta0, ta0, t0 # ta0 = 0xffee00cc
or ta1, ta1, t1 # ta1 = 0xbbaa0088
srl t0, a0, 8 # t0 = 0x00ccddee
srl t1, a1, 8 # t1 = 0x008899aa
and t0, t0, 0xff00 # t0 = 0x0000dd00
and t1, t1, 0xff00 # t1 = 0x00009900
or v1, ta0, t0 # v1 = 0xffeeddcc
or v0, ta1, t1 # v0 = 0xbbaa9988
j ra
#endif /* defined(__mips_o32) */
END(bswap64)