445 lines
13 KiB
C
445 lines
13 KiB
C
/** @file
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* IPRT - Assembly Routines for Optimizing some Integers Math Operations.
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*/
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/*
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* Copyright (C) 2006-2023 Oracle and/or its affiliates.
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*
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* This file is part of VirtualBox base platform packages, as
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* available from https://www.virtualbox.org.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation, in version 3 of the
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* License.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, see <https://www.gnu.org/licenses>.
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*
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* The contents of this file may alternatively be used under the terms
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* of the Common Development and Distribution License Version 1.0
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* (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
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* in the VirtualBox distribution, in which case the provisions of the
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* CDDL are applicable instead of those of the GPL.
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*
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* You may elect to license modified versions of this file under the
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* terms and conditions of either the GPL or the CDDL or both.
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*
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* SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
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*/
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#ifndef IPRT_INCLUDED_asm_math_h
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#define IPRT_INCLUDED_asm_math_h
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#ifndef RT_WITHOUT_PRAGMA_ONCE
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# pragma once
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#endif
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#include <iprt/types.h>
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#if defined(_MSC_VER) && RT_INLINE_ASM_USES_INTRIN
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/* Emit the intrinsics at all optimization levels. */
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# include <iprt/sanitized/intrin.h>
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# pragma intrinsic(__emul)
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# pragma intrinsic(__emulu)
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# ifdef RT_ARCH_AMD64
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# pragma intrinsic(_mul128)
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# pragma intrinsic(_umul128)
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# endif
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#endif
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/** @defgroup grp_rt_asm_math Interger Math Optimizations
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* @ingroup grp_rt_asm
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* @{ */
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/**
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* Multiplies two unsigned 32-bit values returning an unsigned 64-bit result.
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*
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* @returns u32F1 * u32F2.
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*/
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#if RT_INLINE_ASM_EXTERNAL && !RT_INLINE_ASM_USES_INTRIN && defined(RT_ARCH_X86)
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DECLASM(uint64_t) ASMMult2xU32RetU64(uint32_t u32F1, uint32_t u32F2);
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#else
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DECLINLINE(uint64_t) ASMMult2xU32RetU64(uint32_t u32F1, uint32_t u32F2)
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{
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# ifdef RT_ARCH_X86
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uint64_t u64;
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# if RT_INLINE_ASM_GNU_STYLE
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__asm__ __volatile__("mull %%edx"
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: "=A" (u64)
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: "a" (u32F2), "d" (u32F1));
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# elif RT_INLINE_ASM_USES_INTRIN
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u64 = __emulu(u32F1, u32F2);
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# else
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__asm
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{
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mov edx, [u32F1]
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mov eax, [u32F2]
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mul edx
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mov dword ptr [u64], eax
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mov dword ptr [u64 + 4], edx
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}
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# endif
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return u64;
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# else /* generic: */
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return (uint64_t)u32F1 * u32F2;
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# endif
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}
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#endif
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/**
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* Multiplies two signed 32-bit values returning a signed 64-bit result.
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*
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* @returns u32F1 * u32F2.
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*/
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#if RT_INLINE_ASM_EXTERNAL && !RT_INLINE_ASM_USES_INTRIN && defined(RT_ARCH_X86)
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DECLASM(int64_t) ASMMult2xS32RetS64(int32_t i32F1, int32_t i32F2);
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#else
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DECLINLINE(int64_t) ASMMult2xS32RetS64(int32_t i32F1, int32_t i32F2)
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{
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# ifdef RT_ARCH_X86
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int64_t i64;
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# if RT_INLINE_ASM_GNU_STYLE
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__asm__ __volatile__("imull %%edx"
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: "=A" (i64)
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: "a" (i32F2), "d" (i32F1));
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# elif RT_INLINE_ASM_USES_INTRIN
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i64 = __emul(i32F1, i32F2);
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# else
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__asm
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{
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mov edx, [i32F1]
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mov eax, [i32F2]
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imul edx
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mov dword ptr [i64], eax
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mov dword ptr [i64 + 4], edx
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}
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# endif
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return i64;
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# else /* generic: */
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return (int64_t)i32F1 * i32F2;
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# endif
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}
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#endif
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DECLINLINE(uint64_t) ASMMult2xU64Ret2xU64(uint64_t u64F1, uint64_t u64F2, uint64_t *pu64ProdHi)
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{
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#if defined(RT_ARCH_AMD64) && (RT_INLINE_ASM_GNU_STYLE || RT_INLINE_ASM_USES_INTRIN)
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# if RT_INLINE_ASM_GNU_STYLE
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uint64_t u64Low, u64High;
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__asm__ __volatile__("mulq %%rdx"
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: "=a" (u64Low), "=d" (u64High)
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: "0" (u64F1), "1" (u64F2));
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*pu64ProdHi = u64High;
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return u64Low;
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# elif RT_INLINE_ASM_USES_INTRIN
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return _umul128(u64F1, u64F2, pu64ProdHi);
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# else
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# error "hmm"
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# endif
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#else /* generic: */
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/*
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* F1 * F2 = Prod
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* -- --
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* ab * cd = b*d + a*d*10 + b*c*10 + a*c*100
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*
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* Where a, b, c and d are 'digits', and 10 is max digit + 1.
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*
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* Our digits are 32-bit wide, so instead of 10 we multiply by 4G.
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* Prod = F1.s.Lo*F2.s.Lo + F1.s.Hi*F2.s.Lo*4G
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* + F1.s.Lo*F2.s.Hi*4G + F1.s.Hi*F2.s.Hi*4G*4G
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*/
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RTUINT128U Prod;
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RTUINT64U Tmp1;
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uint64_t u64Tmp;
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RTUINT64U F1, F2;
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F1.u = u64F1;
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F2.u = u64F2;
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Prod.s.Lo = ASMMult2xU32RetU64(F1.s.Lo, F2.s.Lo);
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Tmp1.u = ASMMult2xU32RetU64(F1.s.Hi, F2.s.Lo);
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u64Tmp = (uint64_t)Prod.DWords.dw1 + Tmp1.s.Lo;
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Prod.DWords.dw1 = (uint32_t)u64Tmp;
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Prod.s.Hi = Tmp1.s.Hi;
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Prod.s.Hi += u64Tmp >> 32; /* carry */
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Tmp1.u = ASMMult2xU32RetU64(F1.s.Lo, F2.s.Hi);
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u64Tmp = (uint64_t)Prod.DWords.dw1 + Tmp1.s.Lo;
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Prod.DWords.dw1 = (uint32_t)u64Tmp;
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u64Tmp >>= 32; /* carry */
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u64Tmp += Prod.DWords.dw2;
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u64Tmp += Tmp1.s.Hi;
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Prod.DWords.dw2 = (uint32_t)u64Tmp;
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Prod.DWords.dw3 += u64Tmp >> 32; /* carry */
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Prod.s.Hi += ASMMult2xU32RetU64(F1.s.Hi, F2.s.Hi);
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*pu64ProdHi = Prod.s.Hi;
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return Prod.s.Lo;
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#endif
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}
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/**
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* Divides a 64-bit unsigned by a 32-bit unsigned returning an unsigned 32-bit result.
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*
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* @returns u64 / u32.
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*/
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#if RT_INLINE_ASM_EXTERNAL && defined(RT_ARCH_X86)
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DECLASM(uint32_t) ASMDivU64ByU32RetU32(uint64_t u64, uint32_t u32);
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#else
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DECLINLINE(uint32_t) ASMDivU64ByU32RetU32(uint64_t u64, uint32_t u32)
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{
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# ifdef RT_ARCH_X86
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# if RT_INLINE_ASM_GNU_STYLE
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RTCCUINTREG uDummy;
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__asm__ __volatile__("divl %3"
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: "=a" (u32), "=d"(uDummy)
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: "A" (u64), "r" (u32));
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# else
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__asm
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{
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mov eax, dword ptr [u64]
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mov edx, dword ptr [u64 + 4]
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mov ecx, [u32]
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div ecx
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mov [u32], eax
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}
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# endif
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return u32;
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# else /* generic: */
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return (uint32_t)(u64 / u32);
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# endif
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}
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#endif
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/**
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* Divides a 64-bit signed by a 32-bit signed returning a signed 32-bit result.
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*
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* @returns u64 / u32.
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*/
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#if RT_INLINE_ASM_EXTERNAL && defined(RT_ARCH_X86)
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DECLASM(int32_t) ASMDivS64ByS32RetS32(int64_t i64, int32_t i32);
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#else
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DECLINLINE(int32_t) ASMDivS64ByS32RetS32(int64_t i64, int32_t i32)
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{
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# ifdef RT_ARCH_X86
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# if RT_INLINE_ASM_GNU_STYLE
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RTCCUINTREG iDummy;
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__asm__ __volatile__("idivl %3"
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: "=a" (i32), "=d"(iDummy)
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: "A" (i64), "r" (i32));
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# else
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__asm
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{
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mov eax, dword ptr [i64]
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mov edx, dword ptr [i64 + 4]
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mov ecx, [i32]
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idiv ecx
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mov [i32], eax
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}
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# endif
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return i32;
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# else /* generic: */
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return (int32_t)(i64 / i32);
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# endif
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}
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#endif
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/**
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* Performs 64-bit unsigned by a 32-bit unsigned division with a 32-bit unsigned result,
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* returning the rest.
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*
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* @returns u64 % u32.
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*
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* @remarks It is important that the result is <= UINT32_MAX or we'll overflow and crash.
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*/
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#if RT_INLINE_ASM_EXTERNAL && defined(RT_ARCH_X86)
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DECLASM(uint32_t) ASMModU64ByU32RetU32(uint64_t u64, uint32_t u32);
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#else
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DECLINLINE(uint32_t) ASMModU64ByU32RetU32(uint64_t u64, uint32_t u32)
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{
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# ifdef RT_ARCH_X86
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# if RT_INLINE_ASM_GNU_STYLE
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RTCCUINTREG uDummy;
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__asm__ __volatile__("divl %3"
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: "=a" (uDummy), "=d"(u32)
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: "A" (u64), "r" (u32));
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# else
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__asm
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{
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mov eax, dword ptr [u64]
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mov edx, dword ptr [u64 + 4]
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mov ecx, [u32]
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div ecx
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mov [u32], edx
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}
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# endif
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return u32;
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# else /* generic: */
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return (uint32_t)(u64 % u32);
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# endif
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}
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#endif
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/**
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* Performs 64-bit signed by a 32-bit signed division with a 32-bit signed result,
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* returning the rest.
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*
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* @returns u64 % u32.
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*
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* @remarks It is important that the result is <= UINT32_MAX or we'll overflow and crash.
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*/
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#if RT_INLINE_ASM_EXTERNAL && defined(RT_ARCH_X86)
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DECLASM(int32_t) ASMModS64ByS32RetS32(int64_t i64, int32_t i32);
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#else
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DECLINLINE(int32_t) ASMModS64ByS32RetS32(int64_t i64, int32_t i32)
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{
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# ifdef RT_ARCH_X86
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# if RT_INLINE_ASM_GNU_STYLE
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RTCCUINTREG iDummy;
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__asm__ __volatile__("idivl %3"
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: "=a" (iDummy), "=d"(i32)
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: "A" (i64), "r" (i32));
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# else
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__asm
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{
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mov eax, dword ptr [i64]
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mov edx, dword ptr [i64 + 4]
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mov ecx, [i32]
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idiv ecx
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mov [i32], edx
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}
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# endif
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return i32;
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# else /* generic: */
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return (int32_t)(i64 % i32);
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# endif
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}
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#endif
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/**
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* Multiple a 32-bit by a 32-bit integer and divide the result by a 32-bit integer
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* using a 64 bit intermediate result.
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*
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* @returns (u32A * u32B) / u32C.
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* @param u32A The 32-bit value (A).
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* @param u32B The 32-bit value to multiple by A.
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* @param u32C The 32-bit value to divide A*B by.
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*
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* @remarks Architecture specific.
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* @remarks Make sure the result won't ever exceed 32-bit, because hardware
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* exception may be raised if it does.
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* @remarks On x86 this may be used to avoid dragging in 64-bit builtin
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* arithmetics functions.
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*/
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#if RT_INLINE_ASM_EXTERNAL && (defined(RT_ARCH_AMD64) || defined(RT_ARCH_X86))
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DECLASM(uint32_t) ASMMultU32ByU32DivByU32(uint32_t u32A, uint32_t u32B, uint32_t u32C);
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#else
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DECLINLINE(uint32_t) ASMMultU32ByU32DivByU32(uint32_t u32A, uint32_t u32B, uint32_t u32C)
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{
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# if RT_INLINE_ASM_GNU_STYLE && (defined(RT_ARCH_AMD64) || defined(RT_ARCH_X86))
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uint32_t u32Result, u32Spill;
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__asm__ __volatile__("mull %2\n\t"
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"divl %3\n\t"
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: "=&a" (u32Result),
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"=&d" (u32Spill)
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: "r" (u32B),
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"r" (u32C),
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"0" (u32A));
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return u32Result;
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# else
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return (uint32_t)(((uint64_t)u32A * u32B) / u32C);
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# endif
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}
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#endif
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/**
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* Multiple a 64-bit by a 32-bit integer and divide the result by a 32-bit integer
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* using a 96 bit intermediate result.
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*
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* @returns (u64A * u32B) / u32C.
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* @param u64A The 64-bit value.
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* @param u32B The 32-bit value to multiple by A.
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* @param u32C The 32-bit value to divide A*B by.
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*
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* @remarks Architecture specific.
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* @remarks Make sure the result won't ever exceed 64-bit, because hardware
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* exception may be raised if it does.
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* @remarks On x86 this may be used to avoid dragging in 64-bit builtin
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* arithmetics function.
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*/
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#if RT_INLINE_ASM_EXTERNAL || !defined(__GNUC__) || (!defined(RT_ARCH_AMD64) && !defined(RT_ARCH_X86))
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DECLASM(uint64_t) ASMMultU64ByU32DivByU32(uint64_t u64A, uint32_t u32B, uint32_t u32C);
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#else
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DECLINLINE(uint64_t) ASMMultU64ByU32DivByU32(uint64_t u64A, uint32_t u32B, uint32_t u32C)
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{
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# if RT_INLINE_ASM_GNU_STYLE
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# ifdef RT_ARCH_AMD64
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uint64_t u64Result, u64Spill;
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__asm__ __volatile__("mulq %2\n\t"
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"divq %3\n\t"
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: "=&a" (u64Result),
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"=&d" (u64Spill)
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: "r" ((uint64_t)u32B),
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"r" ((uint64_t)u32C),
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"0" (u64A));
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return u64Result;
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# else
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uint32_t u32Dummy;
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uint64_t u64Result;
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__asm__ __volatile__("mull %%ecx \n\t" /* eax = u64Lo.lo = (u64A.lo * u32B).lo
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edx = u64Lo.hi = (u64A.lo * u32B).hi */
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"xchg %%eax,%%esi \n\t" /* esi = u64Lo.lo
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eax = u64A.hi */
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"xchg %%edx,%%edi \n\t" /* edi = u64Low.hi
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edx = u32C */
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"xchg %%edx,%%ecx \n\t" /* ecx = u32C
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edx = u32B */
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"mull %%edx \n\t" /* eax = u64Hi.lo = (u64A.hi * u32B).lo
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edx = u64Hi.hi = (u64A.hi * u32B).hi */
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"addl %%edi,%%eax \n\t" /* u64Hi.lo += u64Lo.hi */
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"adcl $0,%%edx \n\t" /* u64Hi.hi += carry */
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"divl %%ecx \n\t" /* eax = u64Hi / u32C
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edx = u64Hi % u32C */
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"movl %%eax,%%edi \n\t" /* edi = u64Result.hi = u64Hi / u32C */
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"movl %%esi,%%eax \n\t" /* eax = u64Lo.lo */
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"divl %%ecx \n\t" /* u64Result.lo */
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"movl %%edi,%%edx \n\t" /* u64Result.hi */
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: "=A"(u64Result), "=c"(u32Dummy),
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"=S"(u32Dummy), "=D"(u32Dummy)
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: "a"((uint32_t)u64A),
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"S"((uint32_t)(u64A >> 32)),
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"c"(u32B),
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"D"(u32C));
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return u64Result;
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# endif
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# else
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RTUINT64U u;
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uint64_t u64Lo = (uint64_t)(u64A & 0xffffffff) * u32B;
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uint64_t u64Hi = (uint64_t)(u64A >> 32) * u32B;
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u64Hi += (u64Lo >> 32);
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u.s.Hi = (uint32_t)(u64Hi / u32C);
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u.s.Lo = (uint32_t)((((u64Hi % u32C) << 32) + (u64Lo & 0xffffffff)) / u32C);
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return u.u;
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# endif
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}
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#endif
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/** @} */
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#endif /* !IPRT_INCLUDED_asm_math_h */
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