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Diffstat (limited to 'include/iprt/asm-math.h')
| -rw-r--r-- | include/iprt/asm-math.h | 445 |
1 files changed, 445 insertions, 0 deletions
diff --git a/include/iprt/asm-math.h b/include/iprt/asm-math.h new file mode 100644 index 00000000..d379111c --- /dev/null +++ b/include/iprt/asm-math.h @@ -0,0 +1,445 @@ +/** @file + * IPRT - Assembly Routines for Optimizing some Integers Math Operations. + */ + +/* + * Copyright (C) 2006-2022 Oracle and/or its affiliates. + * + * This file is part of VirtualBox base platform packages, as + * available from https://www.virtualbox.org. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation, in version 3 of the + * License. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, see <https://www.gnu.org/licenses>. + * + * The contents of this file may alternatively be used under the terms + * of the Common Development and Distribution License Version 1.0 + * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included + * in the VirtualBox distribution, in which case the provisions of the + * CDDL are applicable instead of those of the GPL. + * + * You may elect to license modified versions of this file under the + * terms and conditions of either the GPL or the CDDL or both. + * + * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0 + */ + +#ifndef IPRT_INCLUDED_asm_math_h +#define IPRT_INCLUDED_asm_math_h +#ifndef RT_WITHOUT_PRAGMA_ONCE +# pragma once +#endif + +#include <iprt/types.h> + +#if defined(_MSC_VER) && RT_INLINE_ASM_USES_INTRIN +/* Emit the intrinsics at all optimization levels. */ +# include <iprt/sanitized/intrin.h> +# pragma intrinsic(__emul) +# pragma intrinsic(__emulu) +# ifdef RT_ARCH_AMD64 +# pragma intrinsic(_mul128) +# pragma intrinsic(_umul128) +# endif +#endif + + +/** @defgroup grp_rt_asm_math Interger Math Optimizations + * @ingroup grp_rt_asm + * @{ */ + +/** + * Multiplies two unsigned 32-bit values returning an unsigned 64-bit result. + * + * @returns u32F1 * u32F2. + */ + +#if RT_INLINE_ASM_EXTERNAL && !RT_INLINE_ASM_USES_INTRIN && defined(RT_ARCH_X86) +DECLASM(uint64_t) ASMMult2xU32RetU64(uint32_t u32F1, uint32_t u32F2); +#else +DECLINLINE(uint64_t) ASMMult2xU32RetU64(uint32_t u32F1, uint32_t u32F2) +{ +# ifdef RT_ARCH_X86 + uint64_t u64; +# if RT_INLINE_ASM_GNU_STYLE + __asm__ __volatile__("mull %%edx" + : "=A" (u64) + : "a" (u32F2), "d" (u32F1)); +# elif RT_INLINE_ASM_USES_INTRIN + u64 = __emulu(u32F1, u32F2); +# else + __asm + { + mov edx, [u32F1] + mov eax, [u32F2] + mul edx + mov dword ptr [u64], eax + mov dword ptr [u64 + 4], edx + } +# endif + return u64; +# else /* generic: */ + return (uint64_t)u32F1 * u32F2; +# endif +} +#endif + + +/** + * Multiplies two signed 32-bit values returning a signed 64-bit result. + * + * @returns u32F1 * u32F2. + */ +#if RT_INLINE_ASM_EXTERNAL && !RT_INLINE_ASM_USES_INTRIN && defined(RT_ARCH_X86) +DECLASM(int64_t) ASMMult2xS32RetS64(int32_t i32F1, int32_t i32F2); +#else +DECLINLINE(int64_t) ASMMult2xS32RetS64(int32_t i32F1, int32_t i32F2) +{ +# ifdef RT_ARCH_X86 + int64_t i64; +# if RT_INLINE_ASM_GNU_STYLE + __asm__ __volatile__("imull %%edx" + : "=A" (i64) + : "a" (i32F2), "d" (i32F1)); +# elif RT_INLINE_ASM_USES_INTRIN + i64 = __emul(i32F1, i32F2); +# else + __asm + { + mov edx, [i32F1] + mov eax, [i32F2] + imul edx + mov dword ptr [i64], eax + mov dword ptr [i64 + 4], edx + } +# endif + return i64; +# else /* generic: */ + return (int64_t)i32F1 * i32F2; +# endif +} +#endif + + +DECLINLINE(uint64_t) ASMMult2xU64Ret2xU64(uint64_t u64F1, uint64_t u64F2, uint64_t *pu64ProdHi) +{ +#if defined(RT_ARCH_AMD64) && (RT_INLINE_ASM_GNU_STYLE || RT_INLINE_ASM_USES_INTRIN) +# if RT_INLINE_ASM_GNU_STYLE + uint64_t u64Low, u64High; + __asm__ __volatile__("mulq %%rdx" + : "=a" (u64Low), "=d" (u64High) + : "0" (u64F1), "1" (u64F2)); + *pu64ProdHi = u64High; + return u64Low; +# elif RT_INLINE_ASM_USES_INTRIN + return _umul128(u64F1, u64F2, pu64ProdHi); +# else +# error "hmm" +# endif +#else /* generic: */ + /* + * F1 * F2 = Prod + * -- -- + * ab * cd = b*d + a*d*10 + b*c*10 + a*c*100 + * + * Where a, b, c and d are 'digits', and 10 is max digit + 1. + * + * Our digits are 32-bit wide, so instead of 10 we multiply by 4G. + * Prod = F1.s.Lo*F2.s.Lo + F1.s.Hi*F2.s.Lo*4G + * + F1.s.Lo*F2.s.Hi*4G + F1.s.Hi*F2.s.Hi*4G*4G + */ + RTUINT128U Prod; + RTUINT64U Tmp1; + uint64_t u64Tmp; + RTUINT64U F1, F2; + F1.u = u64F1; + F2.u = u64F2; + + Prod.s.Lo = ASMMult2xU32RetU64(F1.s.Lo, F2.s.Lo); + + Tmp1.u = ASMMult2xU32RetU64(F1.s.Hi, F2.s.Lo); + u64Tmp = (uint64_t)Prod.DWords.dw1 + Tmp1.s.Lo; + Prod.DWords.dw1 = (uint32_t)u64Tmp; + Prod.s.Hi = Tmp1.s.Hi; + Prod.s.Hi += u64Tmp >> 32; /* carry */ + + Tmp1.u = ASMMult2xU32RetU64(F1.s.Lo, F2.s.Hi); + u64Tmp = (uint64_t)Prod.DWords.dw1 + Tmp1.s.Lo; + Prod.DWords.dw1 = (uint32_t)u64Tmp; + u64Tmp >>= 32; /* carry */ + u64Tmp += Prod.DWords.dw2; + u64Tmp += Tmp1.s.Hi; + Prod.DWords.dw2 = (uint32_t)u64Tmp; + Prod.DWords.dw3 += u64Tmp >> 32; /* carry */ + + Prod.s.Hi += ASMMult2xU32RetU64(F1.s.Hi, F2.s.Hi); + *pu64ProdHi = Prod.s.Hi; + return Prod.s.Lo; +#endif +} + + + +/** + * Divides a 64-bit unsigned by a 32-bit unsigned returning an unsigned 32-bit result. + * + * @returns u64 / u32. + */ +#if RT_INLINE_ASM_EXTERNAL && defined(RT_ARCH_X86) +DECLASM(uint32_t) ASMDivU64ByU32RetU32(uint64_t u64, uint32_t u32); +#else +DECLINLINE(uint32_t) ASMDivU64ByU32RetU32(uint64_t u64, uint32_t u32) +{ +# ifdef RT_ARCH_X86 +# if RT_INLINE_ASM_GNU_STYLE + RTCCUINTREG uDummy; + __asm__ __volatile__("divl %3" + : "=a" (u32), "=d"(uDummy) + : "A" (u64), "r" (u32)); +# else + __asm + { + mov eax, dword ptr [u64] + mov edx, dword ptr [u64 + 4] + mov ecx, [u32] + div ecx + mov [u32], eax + } +# endif + return u32; +# else /* generic: */ + return (uint32_t)(u64 / u32); +# endif +} +#endif + + +/** + * Divides a 64-bit signed by a 32-bit signed returning a signed 32-bit result. + * + * @returns u64 / u32. + */ +#if RT_INLINE_ASM_EXTERNAL && defined(RT_ARCH_X86) +DECLASM(int32_t) ASMDivS64ByS32RetS32(int64_t i64, int32_t i32); +#else +DECLINLINE(int32_t) ASMDivS64ByS32RetS32(int64_t i64, int32_t i32) +{ +# ifdef RT_ARCH_X86 +# if RT_INLINE_ASM_GNU_STYLE + RTCCUINTREG iDummy; + __asm__ __volatile__("idivl %3" + : "=a" (i32), "=d"(iDummy) + : "A" (i64), "r" (i32)); +# else + __asm + { + mov eax, dword ptr [i64] + mov edx, dword ptr [i64 + 4] + mov ecx, [i32] + idiv ecx + mov [i32], eax + } +# endif + return i32; +# else /* generic: */ + return (int32_t)(i64 / i32); +# endif +} +#endif + + +/** + * Performs 64-bit unsigned by a 32-bit unsigned division with a 32-bit unsigned result, + * returning the rest. + * + * @returns u64 % u32. + * + * @remarks It is important that the result is <= UINT32_MAX or we'll overflow and crash. + */ +#if RT_INLINE_ASM_EXTERNAL && defined(RT_ARCH_X86) +DECLASM(uint32_t) ASMModU64ByU32RetU32(uint64_t u64, uint32_t u32); +#else +DECLINLINE(uint32_t) ASMModU64ByU32RetU32(uint64_t u64, uint32_t u32) +{ +# ifdef RT_ARCH_X86 +# if RT_INLINE_ASM_GNU_STYLE + RTCCUINTREG uDummy; + __asm__ __volatile__("divl %3" + : "=a" (uDummy), "=d"(u32) + : "A" (u64), "r" (u32)); +# else + __asm + { + mov eax, dword ptr [u64] + mov edx, dword ptr [u64 + 4] + mov ecx, [u32] + div ecx + mov [u32], edx + } +# endif + return u32; +# else /* generic: */ + return (uint32_t)(u64 % u32); +# endif +} +#endif + + +/** + * Performs 64-bit signed by a 32-bit signed division with a 32-bit signed result, + * returning the rest. + * + * @returns u64 % u32. + * + * @remarks It is important that the result is <= UINT32_MAX or we'll overflow and crash. + */ +#if RT_INLINE_ASM_EXTERNAL && defined(RT_ARCH_X86) +DECLASM(int32_t) ASMModS64ByS32RetS32(int64_t i64, int32_t i32); +#else +DECLINLINE(int32_t) ASMModS64ByS32RetS32(int64_t i64, int32_t i32) +{ +# ifdef RT_ARCH_X86 +# if RT_INLINE_ASM_GNU_STYLE + RTCCUINTREG iDummy; + __asm__ __volatile__("idivl %3" + : "=a" (iDummy), "=d"(i32) + : "A" (i64), "r" (i32)); +# else + __asm + { + mov eax, dword ptr [i64] + mov edx, dword ptr [i64 + 4] + mov ecx, [i32] + idiv ecx + mov [i32], edx + } +# endif + return i32; +# else /* generic: */ + return (int32_t)(i64 % i32); +# endif +} +#endif + + +/** + * Multiple a 32-bit by a 32-bit integer and divide the result by a 32-bit integer + * using a 64 bit intermediate result. + * + * @returns (u32A * u32B) / u32C. + * @param u32A The 32-bit value (A). + * @param u32B The 32-bit value to multiple by A. + * @param u32C The 32-bit value to divide A*B by. + * + * @remarks Architecture specific. + * @remarks Make sure the result won't ever exceed 32-bit, because hardware + * exception may be raised if it does. + * @remarks On x86 this may be used to avoid dragging in 64-bit builtin + * arithmetics functions. + */ +#if RT_INLINE_ASM_EXTERNAL && (defined(RT_ARCH_AMD64) || defined(RT_ARCH_X86)) +DECLASM(uint32_t) ASMMultU32ByU32DivByU32(uint32_t u32A, uint32_t u32B, uint32_t u32C); +#else +DECLINLINE(uint32_t) ASMMultU32ByU32DivByU32(uint32_t u32A, uint32_t u32B, uint32_t u32C) +{ +# if RT_INLINE_ASM_GNU_STYLE && (defined(RT_ARCH_AMD64) || defined(RT_ARCH_X86)) + uint32_t u32Result, u32Spill; + __asm__ __volatile__("mull %2\n\t" + "divl %3\n\t" + : "=&a" (u32Result), + "=&d" (u32Spill) + : "r" (u32B), + "r" (u32C), + "0" (u32A)); + return u32Result; +# else + return (uint32_t)(((uint64_t)u32A * u32B) / u32C); +# endif +} +#endif + + +/** + * Multiple a 64-bit by a 32-bit integer and divide the result by a 32-bit integer + * using a 96 bit intermediate result. + * + * @returns (u64A * u32B) / u32C. + * @param u64A The 64-bit value. + * @param u32B The 32-bit value to multiple by A. + * @param u32C The 32-bit value to divide A*B by. + * + * @remarks Architecture specific. + * @remarks Make sure the result won't ever exceed 64-bit, because hardware + * exception may be raised if it does. + * @remarks On x86 this may be used to avoid dragging in 64-bit builtin + * arithmetics function. + */ +#if RT_INLINE_ASM_EXTERNAL || !defined(__GNUC__) || (!defined(RT_ARCH_AMD64) && !defined(RT_ARCH_X86)) +DECLASM(uint64_t) ASMMultU64ByU32DivByU32(uint64_t u64A, uint32_t u32B, uint32_t u32C); +#else +DECLINLINE(uint64_t) ASMMultU64ByU32DivByU32(uint64_t u64A, uint32_t u32B, uint32_t u32C) +{ +# if RT_INLINE_ASM_GNU_STYLE +# ifdef RT_ARCH_AMD64 + uint64_t u64Result, u64Spill; + __asm__ __volatile__("mulq %2\n\t" + "divq %3\n\t" + : "=&a" (u64Result), + "=&d" (u64Spill) + : "r" ((uint64_t)u32B), + "r" ((uint64_t)u32C), + "0" (u64A)); + return u64Result; +# else + uint32_t u32Dummy; + uint64_t u64Result; + __asm__ __volatile__("mull %%ecx \n\t" /* eax = u64Lo.lo = (u64A.lo * u32B).lo + edx = u64Lo.hi = (u64A.lo * u32B).hi */ + "xchg %%eax,%%esi \n\t" /* esi = u64Lo.lo + eax = u64A.hi */ + "xchg %%edx,%%edi \n\t" /* edi = u64Low.hi + edx = u32C */ + "xchg %%edx,%%ecx \n\t" /* ecx = u32C + edx = u32B */ + "mull %%edx \n\t" /* eax = u64Hi.lo = (u64A.hi * u32B).lo + edx = u64Hi.hi = (u64A.hi * u32B).hi */ + "addl %%edi,%%eax \n\t" /* u64Hi.lo += u64Lo.hi */ + "adcl $0,%%edx \n\t" /* u64Hi.hi += carry */ + "divl %%ecx \n\t" /* eax = u64Hi / u32C + edx = u64Hi % u32C */ + "movl %%eax,%%edi \n\t" /* edi = u64Result.hi = u64Hi / u32C */ + "movl %%esi,%%eax \n\t" /* eax = u64Lo.lo */ + "divl %%ecx \n\t" /* u64Result.lo */ + "movl %%edi,%%edx \n\t" /* u64Result.hi */ + : "=A"(u64Result), "=c"(u32Dummy), + "=S"(u32Dummy), "=D"(u32Dummy) + : "a"((uint32_t)u64A), + "S"((uint32_t)(u64A >> 32)), + "c"(u32B), + "D"(u32C)); + return u64Result; +# endif +# else + RTUINT64U u; + uint64_t u64Lo = (uint64_t)(u64A & 0xffffffff) * u32B; + uint64_t u64Hi = (uint64_t)(u64A >> 32) * u32B; + u64Hi += (u64Lo >> 32); + u.s.Hi = (uint32_t)(u64Hi / u32C); + u.s.Lo = (uint32_t)((((u64Hi % u32C) << 32) + (u64Lo & 0xffffffff)) / u32C); + return u.u; +# endif +} +#endif + +/** @} */ +#endif /* !IPRT_INCLUDED_asm_math_h */ + |