1 /* $NetBSD: memset_arm.S,v 1.2 2013/01/14 19:15:13 matt Exp $ */ 2 3 /*- 4 * Copyright (c) 2012 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Matt Thomas of 3am Software Foundry. 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 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 #include <machine/asm.h> 32 33 #if defined(NEON) 34 #define STORE8 vst1.32 {d0}, [ip:64]! 35 #define STORE16 vst1.32 {d0-d1}, [ip:64]! 36 #define STORE32 vst1.32 {d0-d3}, [ip:64]! 37 #elif defined(VFP) 38 #define STORE8 vstmia ip!, {d0} 39 #define STORE16 vstmia ip!, {d0-d1} 40 #define STORE32 vstmia ip!, {d0-d3} 41 #elif defined(_ARM_ARCH_DWORD_OK) 42 #define STORE8 strd r2, [ip], #8 43 #define STORE16 STORE8; STORE8 44 #define STORE32 STORE16; STORE16 45 #else 46 #define STORE8 stmia ip!, {r2,r3} 47 #define STORE16 STORE8; STORE8 48 #define STORE32 STORE16; STORE16 49 #endif 50 /* 51 * memset: Sets a block of memory to the specified value 52 * Using NEON instructions 53 * 54 * On entry: 55 * r0 - dest address 56 * r1 - byte to write 57 * r2 - number of bytes to write 58 * 59 * On exit: 60 * r0 - dest address 61 */ 62 /* LINTSTUB: Func: void *memset(void *, int, size_t) */ 63 ENTRY(memset) 64 ands r3, r1, #0xff /* We deal with bytes */ 65 orrne r3, r3, r3, lsl #8 /* replicate to all bytes */ 66 orrne r3, r3, r3, lsl #16 /* replicate to all bytes */ 67 movs r1, r2 /* we need r2 & r3 */ 68 RETc(eq) /* return if length is 0 */ 69 mov ip, r0 /* r0 needs to stay the same */ 70 71 cmp r1, #12 /* is this a small memset? *? 72 blt .Lbyte_by_byte /* then do it byte by byte */ 73 74 /* Ok first we will dword align the address */ 75 ands r2, ip, #7 /* grab the bottom three bits */ 76 beq .Lmemset_dwordaligned /* The addr is dword aligned */ 77 78 rsb r2, r2, #8 /* how far until dword aligned? */ 79 sub r1, r1, r2 /* subtract it from remaining length */ 80 mov r2, r3 /* duplicate fill value */ 81 82 tst ip, #1 /* halfword aligned? */ 83 strneb r3, [ip], #1 /* no, write a byte */ 84 tst ip, #2 /* word aligned? */ 85 strneh r3, [ip], #2 /* no, write a halfword */ 86 tst ip, #4 /* dword aligned? */ 87 strne r3, [ip], #4 /* no, write a word */ 88 89 /* We are now doubleword aligned */ 90 .Lmemset_dwordaligned: 91 #if defined(NEON) 92 vdup.8 q0, r3 /* move fill to SIMD */ 93 vmov q1, q0 /* put fill in q1 (d2-d3) */ 94 #elif defined(VFP) 95 mov r2, r3 /* duplicate fill value */ 96 vmov d0, r2, r3 /* move to VFP */ 97 vmov d1, r2, r3 98 vmov d2, r2, r3 99 vmov d3, r2, r3 100 #endif 101 102 #if 1 103 cmp r1, #128 104 blt .Lmemset_mainloop 105 ands r2, ip, #63 /* check for 64-byte alignment */ 106 beq .Lmemset_mainloop 107 /* 108 * Let's align to a 64-byte boundary so that stores don't cross 109 * cacheline boundaries. We also know we have at least 128-bytes to 110 * copy so we don't have to worry about the length at the moment. 111 */ 112 rsb r2, r2, #64 /* how many bytes until 64 bytes */ 113 sub r1, r1, r2 /* subtract from remaining length */ 114 #if !defined(NEON) && !defined(VFP) 115 mov r2, r3 /* put fill back in r2 */ 116 #endif 117 118 tst ip, #8 /* quadword aligned? */ 119 beq 1f /* yes */ 120 STORE8 /* no, store a dword */ 121 1: tst ip, #16 /* octaword aligned? *? 122 beq 2f /* yes */ 123 STORE16 /* no, store a quadword */ 124 2: tst ip, #32 /* 32 word aligned? */ 125 beq .Lmemset_mainloop /* yes */ 126 STORE32 /* no, make 64-byte aligned */ 127 #endif 128 129 .Lmemset_mainloop: 130 #if !defined(NEON) && !defined(VFP) 131 mov r2, r3 /* put fill back in r2 */ 132 #endif 133 subs r1, r1, #64 /* subtract an initial 64 */ 134 blt .Lmemset_lessthan_64bytes 135 136 3: STORE32 /* store first octaword */ 137 STORE32 /* store second octaword */ 138 RETc(eq) /* return if done */ 139 subs r1, r1, #64 /* subtract another 64 */ 140 bge 3b /* and do other if still >= 0 */ 141 .Lmemset_lessthan_64bytes: 142 tst r1, #32 /* do we have 16 bytes left? */ 143 beq .Lmemset_lessthan_32bytes 144 STORE32 /* yes, store an octaword */ 145 bics r1, r1, #32 /* subtract 16 */ 146 RETc(eq) /* return if length is 0 */ 147 .Lmemset_lessthan_32bytes: 148 tst r1, #16 /* do we have 16 bytes left? */ 149 beq .Lmemset_lessthan_16bytes 150 STORE16 /* yes, store a quadword */ 151 bics r1, r1, #16 /* subtract 16 */ 152 RETc(eq) /* return if length is 0 */ 153 .Lmemset_lessthan_16bytes: 154 tst r1, #8 /* do we have 8 bytes left? */ 155 beq .Lmemset_lessthan_8bytes/* no */ 156 STORE8 /* yes, store a dword */ 157 bics r1, r1, #8 /* subtract 8 */ 158 RETc(eq) /* return if length is 0 */ 159 .Lmemset_lessthan_8bytes: 160 tst r1, #4 /* do we have a word left? */ 161 strne r2, [ip], #4 /* yes, so write one */ 162 tst r1, #2 /* do we have a halfword left? */ 163 strneh r2, [ip], #2 /* yes, so write one */ 164 tst r1, #1 /* do we have a byte left? */ 165 strneb r2, [ip], #1 /* yes, so write one */ 166 RET /* return */ 167 168 .Lbyte_by_byte: 169 subs r1, r1, #1 /* can we write a byte? */ 170 RETc(lt) /* no, we're done */ 171 strb r3, [ip], #1 /* yes, so do it */ 172 b .Lbyte_by_byte /* try next byte */ 173 END(memset) 174
Indexes created Sat Sep 20 22:09:52 GMT 2025