1/* 2 * Copyright 2013, winocm. <winocm@icloud.com> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without modification, 6 * are permitted provided that the following conditions are met: 7 * 8 * Redistributions of source code must retain the above copyright notice, this 9 * list of conditions and the following disclaimer. 10 * 11 * Redistributions in binary form must reproduce the above copyright notice, this 12 * list of conditions and the following disclaimer in the documentation and/or 13 * other materials provided with the distribution. 14 * 15 * If you are going to use this software in any form that does not involve 16 * releasing the source to this project or improving it, let me know beforehand. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND 19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 20 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 21 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR 22 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 23 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 24 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON 25 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 27 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 28 */ 29/* 30 * ARM atomic hardware functions. 31 */ 32 33#include <arm/arch.h> 34#include <arm/asm_help.h> 35 36/** 37 * hw_compare_and_store 38 * 39 * Take the value in the destination, compare it to the old value, if equal 40 * atomically write the new value to the address. 41 */ 42.globl _hw_compare_and_store 43.globl _OSCompareAndSwap 44_hw_compare_and_store: 45_OSCompareAndSwap: 46 mov x4, x0 47loop: 48 ldr w3, [x2] 49 mov x0, #0 50 cmp w3, w4 51 b.ne loop_exit 52 b.eq loop_store 53 b loop 54loop_exit: 55 ret lr 56loop_store: 57 str w1, [x2] 58 mov x0, #1 59 ret lr 60 61/* The others. */ 62.align 6 63.globl _hw_atomic_sub 64.globl _hw_atomic_add 65.globl _hw_atomic_and_noret 66.globl _hw_atomic_or_noret 67_hw_atomic_sub: 68 mov x2, x0 69try_sub: 70 ldr x0, [x2] 71 sub x0, x0, x1 72 str x0, [x2] 73 ret lr 74_hw_atomic_add: 75 mov x2, x0 76try_add: 77 ldr x0, [x2] 78 add x0, x0, x1 79 str x0, [x2] 80 ret lr 81_hw_atomic_or_noret: 82 mov x2, x0 83try_or: 84 ldr x0, [x4] 85 orr x0, x0, x1 86 str x0, [x2] 87 ret lr 88_hw_atomic_and_noret: 89 mov x2, x0 90try_and: 91 ldr x0, [x2] 92 and x0, x0, x1 93 str x0, [x2] 94 ret lr 95 96