byte_swap_8.S revision 1.2.48.2
1 /* $NetBSD: byte_swap_8.S,v 1.2.48.2 2020/04/21 19:37:44 martin Exp $ */ 2 3 /*- 4 * Copyright (c) 1991, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Ralph Campbell. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35 #include <mips/asm.h> 36 37 #if defined(LIBC_SCCS) && !defined(lint) 38 RCSID("$NetBSD: byte_swap_8.S,v 1.2.48.2 2020/04/21 19:37:44 martin Exp $") 39 #endif /* LIBC_SCCS and not lint */ 40 41 #undef _LOCORE 42 #define _LOCORE /* XXX not really, just assembly-code source */ 43 #include <machine/endian.h> 44 45 NLEAF(bswap64) # a0 = 0xffeeddccbbaa9988 return 0x8899aabbccddeeff 46 #if (__mips == 32 || __mips == 64) && __mips_isa_rev == 2 47 #if !defined(__mips_o32) 48 /* 49 * If we are on MIPS32r2 or MIPS64r2 use the new instructions. 50 */ 51 dsbh v0, a0 # dwords swap bytes within halfwords 52 dshd v0, v0 # dwords swap halwords within dwords 53 j ra 54 #else /* defined(__mips_o32) */ 55 /* 56 * If we are on MIPS32r2 or MIPS64r2 use the new instructions. 57 * (except we must use the 32bit versions) 58 */ 59 wsbh v1, a0 # word swap bytes within halfwords 60 wsbh v0, a1 # word swap bytes within halfwords 61 rotr v1, v1, 16 # rotate word 16bits and swap word 62 rotr v0, v0, 16 # rotate word 16bits and swap word 63 j ra 64 #endif /* defined(__mips_o32) */ 65 #elif !defined(__mips_o32) 66 # a0 = 0xffeeddccbbaa9988 67 li t0, 0xffff # t0 = 0x000000000000ffff 68 dsll t1, t0, 32 # t1 = 0x0000ffff00000000 69 or t0, t1 # t0 = 0x0000ffff0000ffff 70 dsll t2, t0, 8 # t2 = 0x00ffff0000ffff00 71 xor t2, t0 # t2 = 0x00ff00ff00ff00ff 72 /* 73 * We could swap by halfword, but that would be one instruction longer. 74 */ 75 dsrl ta0, a0, 32 # ta0 = 0x00000000ffeeddcc 76 dsll ta1, a0, 32 # ta1 = 0xbbaa998800000000 77 or a1, ta0, ta1 # a1 = 0xbbaa9988ffeeddcc 78 # words swapped 79 and ta0, a1, t0 # ta0 = 0x000099880000ddcc 80 dsrl ta1, a1, 16 # ta1 = 0x0000bbaa9988ffee 81 and ta1, t0 # ta1 = 0x0000bbaa0000ffee 82 dsll a2, ta0, 16 # a2 = 0x99880000ddcc0000 83 or a2, ta1 # a2 = 0x9988bbaaddccffee 84 # halfwords swapped 85 and ta0, a2, t2 # ta0 = 0x008800aa00cc00ee 86 dsrl ta1, a2, 8 # ta1 = 0x009988bbaaddccff 87 and ta1, t2 # ta1 = 0x009900bb00dd00ff 88 dsll v0, ta0, 8 # v0 = 0x8800aa00cc00ee00 89 or v0, ta1 # v0 = 0x8899aabbccddeeff 90 # bytes swapped 91 j ra 92 #else /* defined(__mips_o32) */ 93 /* 94 * 32bit ABI. 95 */ 96 # a0 = 0xccddeeff 97 # a1 = 0x8899aabb 98 srl t0, a0, 24 # t0 = 0x000000cc 99 srl t1, a1, 24 # t1 = 0x00000088 100 sll ta0, a0, 24 # ta0 = 0xff000000 101 sll ta1, a1, 24 # ta1 = 0xbb000000 102 or ta0, ta0, t0 # ta0 = 0xff0000cc 103 or ta1, ta1, t1 # ta1 = 0xbb000088 104 and t0, a0, 0xff00 # t0 = 0x0000ee00 105 and t1, a1, 0xff00 # t1 = 0x0000aa00 106 sll t0, t0, 8 # t0 = 0x00ee0000 107 sll t1, t1, 8 # t1 = 0x00aa0000 108 or ta0, ta0, t0 # ta0 = 0xffee00cc 109 or ta1, ta1, t1 # ta1 = 0xbbaa0088 110 srl t0, a0, 8 # t0 = 0x00ccddee 111 srl t1, a1, 8 # t1 = 0x008899aa 112 and t0, t0, 0xff00 # t0 = 0x0000dd00 113 and t1, t1, 0xff00 # t1 = 0x00009900 114 or v1, ta0, t0 # v1 = 0xffeeddcc 115 or v0, ta1, t1 # v0 = 0xbbaa9988 116 j ra 117 #endif /* defined(__mips_o32) */ 118 END(bswap64) 119
Indexes created Thu Oct 23 22:10:10 GMT 2025