1 | /** @file
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2 | * IPRT - Assembly Memory Functions.
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3 | */
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4 |
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5 | /*
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6 | * Copyright (C) 2006-2024 Oracle and/or its affiliates.
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7 | *
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8 | * This file is part of VirtualBox base platform packages, as
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9 | * available from https://www.virtualbox.org.
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10 | *
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11 | * This program is free software; you can redistribute it and/or
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12 | * modify it under the terms of the GNU General Public License
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13 | * as published by the Free Software Foundation, in version 3 of the
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14 | * License.
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15 | *
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16 | * This program is distributed in the hope that it will be useful, but
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17 | * WITHOUT ANY WARRANTY; without even the implied warranty of
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18 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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19 | * General Public License for more details.
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20 | *
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21 | * You should have received a copy of the GNU General Public License
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22 | * along with this program; if not, see <https://www.gnu.org/licenses>.
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23 | *
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24 | * The contents of this file may alternatively be used under the terms
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25 | * of the Common Development and Distribution License Version 1.0
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26 | * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
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27 | * in the VirtualBox distribution, in which case the provisions of the
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28 | * CDDL are applicable instead of those of the GPL.
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29 | *
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30 | * You may elect to license modified versions of this file under the
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31 | * terms and conditions of either the GPL or the CDDL or both.
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32 | *
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33 | * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
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34 | */
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35 |
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36 | #ifndef IPRT_INCLUDED_asm_mem_h
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37 | #define IPRT_INCLUDED_asm_mem_h
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38 | #ifndef RT_WITHOUT_PRAGMA_ONCE
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39 | # pragma once
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40 | #endif
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41 |
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42 | #include <iprt/cdefs.h>
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43 | #include <iprt/types.h>
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44 | #include <iprt/assert.h>
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45 |
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46 | #if defined(_MSC_VER) && RT_INLINE_ASM_USES_INTRIN
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47 | /* Emit the intrinsics at all optimization levels. */
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48 | # include <iprt/sanitized/intrin.h>
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49 | # if defined(RT_ARCH_X86) || defined(RT_ARCH_AMD64)
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50 | # pragma intrinsic(__cpuid)
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51 | # pragma intrinsic(__stosd)
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52 | # pragma intrinsic(__stosw)
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53 | # pragma intrinsic(__stosb)
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54 | # ifdef RT_ARCH_AMD64
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55 | # pragma intrinsic(__stosq)
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56 | # endif
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57 | # elif defined(RT_ARCH_ARM64) || defined(RT_ARCH_X86)
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58 | # pragma intrinsic(__iso_volatile_load8)
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59 | # endif
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60 | #endif
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61 |
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62 |
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63 | /*
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64 | * Undefine all symbols we have Watcom C/C++ #pragma aux'es for.
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65 | */
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66 | #if defined(__WATCOMC__) && ARCH_BITS == 16 && defined(RT_ARCH_X86)
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67 | # include "asm-mem-watcom-x86-16.h"
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68 | #elif defined(__WATCOMC__) && ARCH_BITS == 32 && defined(RT_ARCH_X86)
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69 | # include "asm-mem-watcom-x86-32.h"
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70 | #endif
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71 |
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72 |
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73 |
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74 | /** @defgroup grp_rt_asm_mem ASM - Memory Assembly Routines
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75 | * @ingroup grp_rt_asm
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76 | * @{
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77 | */
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78 |
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79 | /**
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80 | * Zeros a memory block with a 32-bit aligned size.
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81 | *
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82 | * @param pv Pointer to the memory block.
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83 | * @param cb Number of bytes in the block. This MUST be aligned on 32-bit!
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84 | */
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85 | #if (RT_INLINE_ASM_EXTERNAL && !RT_INLINE_ASM_USES_INTRIN) || (!defined(RT_ARCH_AMD64) && !defined(RT_ARCH_X86))
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86 | RT_ASM_DECL_PRAGMA_WATCOM(void) ASMMemZero32(volatile void RT_FAR *pv, size_t cb) RT_NOTHROW_PROTO;
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87 | #else
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88 | DECLINLINE(void) ASMMemZero32(volatile void RT_FAR *pv, size_t cb) RT_NOTHROW_DEF
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89 | {
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90 | # if RT_INLINE_ASM_USES_INTRIN
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91 | # ifdef RT_ARCH_AMD64
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92 | if (!(cb & 7))
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93 | __stosq((unsigned __int64 RT_FAR *)pv, 0, cb / 8);
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94 | else
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95 | # endif
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96 | __stosd((unsigned long RT_FAR *)pv, 0, cb / 4);
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97 |
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98 | # elif RT_INLINE_ASM_GNU_STYLE
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99 | __asm__ __volatile__("rep stosl"
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100 | : "=D" (pv),
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101 | "=c" (cb)
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102 | : "0" (pv),
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103 | "1" (cb >> 2),
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104 | "a" (0)
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105 | : "memory");
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106 | # else
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107 | __asm
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108 | {
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109 | xor eax, eax
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110 | # ifdef RT_ARCH_AMD64
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111 | mov rcx, [cb]
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112 | shr rcx, 2
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113 | mov rdi, [pv]
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114 | # else
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115 | mov ecx, [cb]
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116 | shr ecx, 2
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117 | mov edi, [pv]
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118 | # endif
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119 | rep stosd
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120 | }
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121 | # endif
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122 | }
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123 | #endif
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124 |
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125 |
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126 | /**
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127 | * Fills a memory block with a 32-bit aligned size.
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128 | *
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129 | * @param pv Pointer to the memory block.
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130 | * @param cb Number of bytes in the block. This MUST be aligned on 32-bit!
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131 | * @param u32 The value to fill with.
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132 | */
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133 | #if (RT_INLINE_ASM_EXTERNAL && !RT_INLINE_ASM_USES_INTRIN) || (!defined(RT_ARCH_AMD64) && !defined(RT_ARCH_X86))
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134 | RT_ASM_DECL_PRAGMA_WATCOM(void) ASMMemFill32(volatile void RT_FAR *pv, size_t cb, uint32_t u32) RT_NOTHROW_PROTO;
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135 | #else
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136 | DECLINLINE(void) ASMMemFill32(volatile void RT_FAR *pv, size_t cb, uint32_t u32) RT_NOTHROW_DEF
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137 | {
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138 | Assert(!(cb & 3));
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139 | Assert(cb > 0);
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140 | # if RT_INLINE_ASM_USES_INTRIN
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141 | # ifdef RT_ARCH_AMD64
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142 | if (!(cb & 7))
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143 | __stosq((unsigned __int64 RT_FAR *)pv, RT_MAKE_U64(u32, u32), cb / 8);
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144 | else
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145 | # endif
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146 | __stosd((unsigned long RT_FAR *)pv, u32, cb / 4);
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147 |
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148 | # elif RT_INLINE_ASM_GNU_STYLE
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149 | __asm__ __volatile__("rep stosl"
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150 | : "=D" (pv),
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151 | "=c" (cb)
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152 | : "0" (pv),
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153 | "1" (cb >> 2),
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154 | "a" (u32)
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155 | : "memory");
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156 | # else
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157 | __asm
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158 | {
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159 | # ifdef RT_ARCH_AMD64
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160 | mov rcx, [cb]
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161 | shr rcx, 2
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162 | mov rdi, [pv]
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163 | # else
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164 | mov ecx, [cb]
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165 | shr ecx, 2
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166 | mov edi, [pv]
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167 | # endif
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168 | mov eax, [u32]
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169 | rep stosd
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170 | }
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171 | # endif
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172 | }
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173 | #endif
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174 |
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175 |
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176 | /**
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177 | * Checks if a memory block is all zeros.
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178 | *
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179 | * @returns Pointer to the first non-zero byte.
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180 | * @returns NULL if all zero.
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181 | *
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182 | * @param pv Pointer to the memory block.
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183 | * @param cb Number of bytes in the block.
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184 | */
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185 | #if !defined(RDESKTOP) && (!defined(RT_OS_LINUX) || !defined(__KERNEL__))
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186 | DECLASM(void RT_FAR *) ASMMemFirstNonZero(void const RT_FAR *pv, size_t cb) RT_NOTHROW_PROTO;
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187 | #else
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188 | DECLINLINE(void RT_FAR *) ASMMemFirstNonZero(void const RT_FAR *pv, size_t cb) RT_NOTHROW_DEF
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189 | {
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190 | /** @todo replace with ASMMemFirstNonZero-generic.cpp in kernel modules. */
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191 | uint8_t const *pb = (uint8_t const RT_FAR *)pv;
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192 | for (; cb; cb--, pb++)
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193 | if (RT_LIKELY(*pb == 0))
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194 | { /* likely */ }
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195 | else
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196 | return (void RT_FAR *)pb;
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197 | return NULL;
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198 | }
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199 | #endif
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200 |
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201 |
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202 | /**
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203 | * Checks if a memory block is all zeros.
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204 | *
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205 | * @returns true if zero, false if not.
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206 | *
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207 | * @param pv Pointer to the memory block.
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208 | * @param cb Number of bytes in the block.
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209 | *
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210 | * @sa ASMMemFirstNonZero
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211 | */
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212 | DECLINLINE(bool) ASMMemIsZero(void const RT_FAR *pv, size_t cb) RT_NOTHROW_DEF
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213 | {
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214 | return ASMMemFirstNonZero(pv, cb) == NULL;
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215 | }
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216 |
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217 |
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218 | /**
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219 | * Checks if a memory block is filled with the specified byte, returning the
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220 | * first mismatch.
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221 | *
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222 | * This is sort of an inverted memchr.
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223 | *
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224 | * @returns Pointer to the byte which doesn't equal u8.
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225 | * @returns NULL if all equal to u8.
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226 | *
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227 | * @param pv Pointer to the memory block.
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228 | * @param cb Number of bytes in the block.
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229 | * @param u8 The value it's supposed to be filled with.
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230 | *
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231 | * @remarks No alignment requirements.
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232 | */
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233 | #if (!defined(RT_OS_LINUX) || !defined(__KERNEL__)) \
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234 | && (!defined(RT_OS_FREEBSD) || !defined(_KERNEL))
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235 | DECLASM(void *) ASMMemFirstMismatchingU8(void const RT_FAR *pv, size_t cb, uint8_t u8) RT_NOTHROW_PROTO;
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236 | #else
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237 | DECLINLINE(void *) ASMMemFirstMismatchingU8(void const RT_FAR *pv, size_t cb, uint8_t u8) RT_NOTHROW_DEF
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238 | {
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239 | /** @todo replace with ASMMemFirstMismatchingU8-generic.cpp in kernel modules. */
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240 | uint8_t const *pb = (uint8_t const RT_FAR *)pv;
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241 | for (; cb; cb--, pb++)
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242 | if (RT_LIKELY(*pb == u8))
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243 | { /* likely */ }
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244 | else
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245 | return (void *)pb;
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246 | return NULL;
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247 | }
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248 | #endif
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249 |
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250 |
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251 | /**
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252 | * Checks if a memory block is filled with the specified byte.
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253 | *
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254 | * @returns true if all matching, false if not.
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255 | *
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256 | * @param pv Pointer to the memory block.
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257 | * @param cb Number of bytes in the block.
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258 | * @param u8 The value it's supposed to be filled with.
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259 | *
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260 | * @remarks No alignment requirements.
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261 | */
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262 | DECLINLINE(bool) ASMMemIsAllU8(void const RT_FAR *pv, size_t cb, uint8_t u8) RT_NOTHROW_DEF
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263 | {
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264 | return ASMMemFirstMismatchingU8(pv, cb, u8) == NULL;
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265 | }
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266 |
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267 |
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268 | /**
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269 | * Checks if a memory block is filled with the specified 32-bit value.
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270 | *
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271 | * This is a sort of inverted memchr.
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272 | *
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273 | * @returns Pointer to the first value which doesn't equal u32.
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274 | * @returns NULL if all equal to u32.
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275 | *
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276 | * @param pv Pointer to the memory block.
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277 | * @param cb Number of bytes in the block. This MUST be aligned on 32-bit!
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278 | * @param u32 The value it's supposed to be filled with.
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279 | */
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280 | DECLINLINE(uint32_t RT_FAR *) ASMMemFirstMismatchingU32(void const RT_FAR *pv, size_t cb, uint32_t u32) RT_NOTHROW_DEF
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281 | {
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282 | /** @todo rewrite this in inline assembly? */
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283 | uint32_t const RT_FAR *pu32 = (uint32_t const RT_FAR *)pv;
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284 | for (; cb; cb -= 4, pu32++)
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285 | if (RT_LIKELY(*pu32 == u32))
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286 | { /* likely */ }
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287 | else
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288 | return (uint32_t RT_FAR *)pu32;
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289 | return NULL;
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290 | }
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291 |
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292 |
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293 | /**
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294 | * Probes a byte pointer for read access.
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295 | *
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296 | * While the function will not fault if the byte is not read accessible,
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297 | * the idea is to do this in a safe place like before acquiring locks
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298 | * and such like.
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299 | *
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300 | * Also, this functions guarantees that an eager compiler is not going
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301 | * to optimize the probing away.
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302 | *
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303 | * @param pvByte Pointer to the byte.
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304 | */
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305 | #if RT_INLINE_ASM_EXTERNAL_TMP_ARM
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306 | RT_ASM_DECL_PRAGMA_WATCOM(uint8_t) ASMProbeReadByte(const void RT_FAR *pvByte) RT_NOTHROW_PROTO;
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307 | #else
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308 | DECLINLINE(uint8_t) ASMProbeReadByte(const void RT_FAR *pvByte) RT_NOTHROW_DEF
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309 | {
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310 | # if defined(RT_ARCH_AMD64) || defined(RT_ARCH_X86)
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311 | uint8_t u8;
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312 | # if RT_INLINE_ASM_GNU_STYLE
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313 | __asm__ __volatile__("movb %1, %0\n\t"
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314 | : "=q" (u8)
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315 | : "m" (*(const uint8_t *)pvByte));
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316 | # else
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317 | __asm
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318 | {
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319 | # ifdef RT_ARCH_AMD64
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320 | mov rax, [pvByte]
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321 | mov al, [rax]
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322 | # else
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323 | mov eax, [pvByte]
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324 | mov al, [eax]
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325 | # endif
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326 | mov [u8], al
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327 | }
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328 | # endif
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329 | return u8;
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330 |
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331 | # elif defined(RT_ARCH_ARM64) || defined(RT_ARCH_ARM32)
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332 | # if defined(RT_INLINE_ASM_USES_INTRIN)
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333 | return (uint8_t)__iso_volatile_load8((volatile const char *)pvByte);
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334 | # else
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335 | uint32_t u32;
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336 | __asm__ __volatile__("Lstart_ASMProbeReadByte_%=:\n\t"
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337 | # if defined(RT_ARCH_ARM64)
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338 | "ldxrb %w[uDst], %[pMem]\n\t"
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339 | # else
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340 | "ldrexb %[uDst], %[pMem]\n\t"
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341 | # endif
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342 | : [uDst] "=&r" (u32)
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343 | : [pMem] "Q" (*(uint8_t const *)pvByte));
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344 | return (uint8_t)u32;
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345 | # endif
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346 |
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347 | # else
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348 | # error "Port me"
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349 | # endif
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350 | }
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351 | #endif
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352 |
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353 | /** @} */
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354 |
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355 | /*
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356 | * Include #pragma aux definitions for Watcom C/C++.
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357 | */
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358 | #if defined(__WATCOMC__) && ARCH_BITS == 16 && defined(RT_ARCH_X86)
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359 | # define IPRT_ASM_WATCOM_X86_16_WITH_PRAGMAS
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360 | # undef IPRT_INCLUDED_asm_mem_watcom_x86_16_h
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361 | # include "asm-mem-watcom-x86-16.h"
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362 | #elif defined(__WATCOMC__) && ARCH_BITS == 32 && defined(RT_ARCH_X86)
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363 | # define IPRT_ASM_WATCOM_X86_32_WITH_PRAGMAS
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364 | # undef IPRT_INCLUDED_asm_mem_watcom_x86_32_h
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365 | # include "asm-mem-watcom-x86-32.h"
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366 | #endif
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367 |
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368 | #endif /* !IPRT_INCLUDED_asm_mem_h */
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369 |
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