github.com/rohankumardubey/syslog-redirector-golang@v0.0.0-20140320174030-4859f03d829a/src/pkg/runtime/memclr_arm.s (about) 1 // Inferno's libkern/memset-arm.s 2 // http://code.google.com/p/inferno-os/source/browse/libkern/memset-arm.s 3 // 4 // Copyright © 1994-1999 Lucent Technologies Inc. All rights reserved. 5 // Revisions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com). All rights reserved. 6 // Portions Copyright 2009 The Go Authors. All rights reserved. 7 // 8 // Permission is hereby granted, free of charge, to any person obtaining a copy 9 // of this software and associated documentation files (the "Software"), to deal 10 // in the Software without restriction, including without limitation the rights 11 // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 12 // copies of the Software, and to permit persons to whom the Software is 13 // furnished to do so, subject to the following conditions: 14 // 15 // The above copyright notice and this permission notice shall be included in 16 // all copies or substantial portions of the Software. 17 // 18 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 19 // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 20 // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 21 // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 22 // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 23 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 24 // THE SOFTWARE. 25 26 #include "../../cmd/ld/textflag.h" 27 28 TO = 8 29 TOE = 11 30 N = 12 31 TMP = 12 /* N and TMP don't overlap */ 32 33 TEXT runtime·memclr(SB),NOSPLIT,$0-8 34 MOVW ptr+0(FP), R(TO) 35 MOVW n+4(FP), R(N) 36 MOVW $0, R(0) 37 38 ADD R(N), R(TO), R(TOE) /* to end pointer */ 39 40 CMP $4, R(N) /* need at least 4 bytes to copy */ 41 BLT _1tail 42 43 AND $0xFF, R(0) /* it's a byte */ 44 SLL $8, R(0), R(TMP) /* replicate to a word */ 45 ORR R(TMP), R(0) 46 SLL $16, R(0), R(TMP) 47 ORR R(TMP), R(0) 48 49 _4align: /* align on 4 */ 50 AND.S $3, R(TO), R(TMP) 51 BEQ _4aligned 52 53 MOVBU.P R(0), 1(R(TO)) /* implicit write back */ 54 B _4align 55 56 _4aligned: 57 SUB $31, R(TOE), R(TMP) /* do 32-byte chunks if possible */ 58 CMP R(TMP), R(TO) 59 BHS _4tail 60 61 MOVW R0, R1 /* replicate */ 62 MOVW R0, R2 63 MOVW R0, R3 64 MOVW R0, R4 65 MOVW R0, R5 66 MOVW R0, R6 67 MOVW R0, R7 68 69 _f32loop: 70 CMP R(TMP), R(TO) 71 BHS _4tail 72 73 MOVM.IA.W [R0-R7], (R(TO)) 74 B _f32loop 75 76 _4tail: 77 SUB $3, R(TOE), R(TMP) /* do remaining words if possible */ 78 _4loop: 79 CMP R(TMP), R(TO) 80 BHS _1tail 81 82 MOVW.P R(0), 4(R(TO)) /* implicit write back */ 83 B _4loop 84 85 _1tail: 86 CMP R(TO), R(TOE) 87 BEQ _return 88 89 MOVBU.P R(0), 1(R(TO)) /* implicit write back */ 90 B _1tail 91 92 _return: 93 RET