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source: vbox/trunk/include/iprt/asm-math.h@ 35199

Last change on this file since 35199 was 29257, checked in by vboxsync, 15 years ago

asm-math.h: opps (ASMMultU64ByU32DivByU32)
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1/** @file
2 * IPRT - Assembly Routines for Optimizing some Integers Math Operations.
3 */
4
5/*
6 * Copyright (C) 2006-2010 Oracle Corporation
7 *
8 * This file is part of VirtualBox Open Source Edition (OSE), as
9 * available from http://www.virtualbox.org. This file is free software;
10 * you can redistribute it and/or modify it under the terms of the GNU
11 * General Public License (GPL) as published by the Free Software
12 * Foundation, in version 2 as it comes in the "COPYING" file of the
13 * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
14 * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
15 *
16 * The contents of this file may alternatively be used under the terms
17 * of the Common Development and Distribution License Version 1.0
18 * (CDDL) only, as it comes in the "COPYING.CDDL" file of the
19 * VirtualBox OSE distribution, in which case the provisions of the
20 * CDDL are applicable instead of those of the GPL.
21 *
22 * You may elect to license modified versions of this file under the
23 * terms and conditions of either the GPL or the CDDL or both.
24 */
25
26#ifndef ___iprt_asm_math_h
27#define ___iprt_asm_math_h
28
29#include <iprt/types.h>
30
31
32/** @defgroup grp_rt_asm_math Interger Math Optimizations
33 * @ingroup grp_rt_asm
34 * @{ */
35
36/**
37 * Multiplies two unsigned 32-bit values returning an unsigned 64-bit result.
38 *
39 * @returns u32F1 * u32F2.
40 */
41#if RT_INLINE_ASM_EXTERNAL && defined(RT_ARCH_X86)
42DECLASM(uint64_t) ASMMult2xU32RetU64(uint32_t u32F1, uint32_t u32F2);
43#else
44DECLINLINE(uint64_t) ASMMult2xU32RetU64(uint32_t u32F1, uint32_t u32F2)
45{
46# ifdef RT_ARCH_X86
47 uint64_t u64;
48# if RT_INLINE_ASM_GNU_STYLE
49 __asm__ __volatile__("mull %%edx"
50 : "=A" (u64)
51 : "a" (u32F2), "d" (u32F1));
52# else
53 __asm
54 {
55 mov edx, [u32F1]
56 mov eax, [u32F2]
57 mul edx
58 mov dword ptr [u64], eax
59 mov dword ptr [u64 + 4], edx
60 }
61# endif
62 return u64;
63# else /* generic: */
64 return (uint64_t)u32F1 * u32F2;
65# endif
66}
67#endif
68
69
70/**
71 * Multiplies two signed 32-bit values returning a signed 64-bit result.
72 *
73 * @returns u32F1 * u32F2.
74 */
75#if RT_INLINE_ASM_EXTERNAL && defined(RT_ARCH_X86)
76DECLASM(int64_t) ASMMult2xS32RetS64(int32_t i32F1, int32_t i32F2);
77#else
78DECLINLINE(int64_t) ASMMult2xS32RetS64(int32_t i32F1, int32_t i32F2)
79{
80# ifdef RT_ARCH_X86
81 int64_t i64;
82# if RT_INLINE_ASM_GNU_STYLE
83 __asm__ __volatile__("imull %%edx"
84 : "=A" (i64)
85 : "a" (i32F2), "d" (i32F1));
86# else
87 __asm
88 {
89 mov edx, [i32F1]
90 mov eax, [i32F2]
91 imul edx
92 mov dword ptr [i64], eax
93 mov dword ptr [i64 + 4], edx
94 }
95# endif
96 return i64;
97# else /* generic: */
98 return (int64_t)i32F1 * i32F2;
99# endif
100}
101#endif
102
103
104/**
105 * Divides a 64-bit unsigned by a 32-bit unsigned returning an unsigned 32-bit result.
106 *
107 * @returns u64 / u32.
108 */
109#if RT_INLINE_ASM_EXTERNAL && defined(RT_ARCH_X86)
110DECLASM(uint32_t) ASMDivU64ByU32RetU32(uint64_t u64, uint32_t u32);
111#else
112DECLINLINE(uint32_t) ASMDivU64ByU32RetU32(uint64_t u64, uint32_t u32)
113{
114# ifdef RT_ARCH_X86
115# if RT_INLINE_ASM_GNU_STYLE
116 RTCCUINTREG uDummy;
117 __asm__ __volatile__("divl %3"
118 : "=a" (u32), "=d"(uDummy)
119 : "A" (u64), "r" (u32));
120# else
121 __asm
122 {
123 mov eax, dword ptr [u64]
124 mov edx, dword ptr [u64 + 4]
125 mov ecx, [u32]
126 div ecx
127 mov [u32], eax
128 }
129# endif
130 return u32;
131# else /* generic: */
132 return (uint32_t)(u64 / u32);
133# endif
134}
135#endif
136
137
138/**
139 * Divides a 64-bit signed by a 32-bit signed returning a signed 32-bit result.
140 *
141 * @returns u64 / u32.
142 */
143#if RT_INLINE_ASM_EXTERNAL && defined(RT_ARCH_X86)
144DECLASM(int32_t) ASMDivS64ByS32RetS32(int64_t i64, int32_t i32);
145#else
146DECLINLINE(int32_t) ASMDivS64ByS32RetS32(int64_t i64, int32_t i32)
147{
148# ifdef RT_ARCH_X86
149# if RT_INLINE_ASM_GNU_STYLE
150 RTCCUINTREG iDummy;
151 __asm__ __volatile__("idivl %3"
152 : "=a" (i32), "=d"(iDummy)
153 : "A" (i64), "r" (i32));
154# else
155 __asm
156 {
157 mov eax, dword ptr [i64]
158 mov edx, dword ptr [i64 + 4]
159 mov ecx, [i32]
160 idiv ecx
161 mov [i32], eax
162 }
163# endif
164 return i32;
165# else /* generic: */
166 return (int32_t)(i64 / i32);
167# endif
168}
169#endif
170
171
172/**
173 * Performs 64-bit unsigned by a 32-bit unsigned division with a 32-bit unsigned result,
174 * returning the rest.
175 *
176 * @returns u64 % u32.
177 *
178 * @remarks It is important that the result is <= UINT32_MAX or we'll overflow and crash.
179 */
180#if RT_INLINE_ASM_EXTERNAL && defined(RT_ARCH_X86)
181DECLASM(uint32_t) ASMModU64ByU32RetU32(uint64_t u64, uint32_t u32);
182#else
183DECLINLINE(uint32_t) ASMModU64ByU32RetU32(uint64_t u64, uint32_t u32)
184{
185# ifdef RT_ARCH_X86
186# if RT_INLINE_ASM_GNU_STYLE
187 RTCCUINTREG uDummy;
188 __asm__ __volatile__("divl %3"
189 : "=a" (uDummy), "=d"(u32)
190 : "A" (u64), "r" (u32));
191# else
192 __asm
193 {
194 mov eax, dword ptr [u64]
195 mov edx, dword ptr [u64 + 4]
196 mov ecx, [u32]
197 div ecx
198 mov [u32], edx
199 }
200# endif
201 return u32;
202# else /* generic: */
203 return (uint32_t)(u64 % u32);
204# endif
205}
206#endif
207
208
209/**
210 * Performs 64-bit signed by a 32-bit signed division with a 32-bit signed result,
211 * returning the rest.
212 *
213 * @returns u64 % u32.
214 *
215 * @remarks It is important that the result is <= UINT32_MAX or we'll overflow and crash.
216 */
217#if RT_INLINE_ASM_EXTERNAL && defined(RT_ARCH_X86)
218DECLASM(int32_t) ASMModS64ByS32RetS32(int64_t i64, int32_t i32);
219#else
220DECLINLINE(int32_t) ASMModS64ByS32RetS32(int64_t i64, int32_t i32)
221{
222# ifdef RT_ARCH_X86
223# if RT_INLINE_ASM_GNU_STYLE
224 RTCCUINTREG iDummy;
225 __asm__ __volatile__("idivl %3"
226 : "=a" (iDummy), "=d"(i32)
227 : "A" (i64), "r" (i32));
228# else
229 __asm
230 {
231 mov eax, dword ptr [i64]
232 mov edx, dword ptr [i64 + 4]
233 mov ecx, [i32]
234 idiv ecx
235 mov [i32], edx
236 }
237# endif
238 return i32;
239# else /* generic: */
240 return (int32_t)(i64 % i32);
241# endif
242}
243#endif
244
245
246/**
247 * Multiple a 64-bit by a 32-bit integer and divide the result by a 32-bit integer
248 * using a 96 bit intermediate result.
249 * @note Don't use 64-bit C arithmetic here since some gcc compilers generate references to
250 * __udivdi3 and __umoddi3 even if this inline function is not used.
251 *
252 * @returns (u64A * u32B) / u32C.
253 * @param u64A The 64-bit value.
254 * @param u32B The 32-bit value to multiple by A.
255 * @param u32C The 32-bit value to divide A*B by.
256 *
257 * @remarks Architecture specific.
258 */
259#if RT_INLINE_ASM_EXTERNAL || !defined(__GNUC__) || (!defined(RT_ARCH_AMD64) && !defined(RT_ARCH_X86))
260DECLASM(uint64_t) ASMMultU64ByU32DivByU32(uint64_t u64A, uint32_t u32B, uint32_t u32C);
261#else
262DECLINLINE(uint64_t) ASMMultU64ByU32DivByU32(uint64_t u64A, uint32_t u32B, uint32_t u32C)
263{
264# if RT_INLINE_ASM_GNU_STYLE
265# ifdef RT_ARCH_AMD64
266 uint64_t u64Result, u64Spill;
267 __asm__ __volatile__("mulq %2\n\t"
268 "divq %3\n\t"
269 : "=a" (u64Result),
270 "=d" (u64Spill)
271 : "r" ((uint64_t)u32B),
272 "r" ((uint64_t)u32C),
273 "0" (u64A),
274 "1" (0));
275 return u64Result;
276# else
277 uint32_t u32Dummy;
278 uint64_t u64Result;
279 __asm__ __volatile__("mull %%ecx \n\t" /* eax = u64Lo.lo = (u64A.lo * u32B).lo
280 edx = u64Lo.hi = (u64A.lo * u32B).hi */
281 "xchg %%eax,%%esi \n\t" /* esi = u64Lo.lo
282 eax = u64A.hi */
283 "xchg %%edx,%%edi \n\t" /* edi = u64Low.hi
284 edx = u32C */
285 "xchg %%edx,%%ecx \n\t" /* ecx = u32C
286 edx = u32B */
287 "mull %%edx \n\t" /* eax = u64Hi.lo = (u64A.hi * u32B).lo
288 edx = u64Hi.hi = (u64A.hi * u32B).hi */
289 "addl %%edi,%%eax \n\t" /* u64Hi.lo += u64Lo.hi */
290 "adcl $0,%%edx \n\t" /* u64Hi.hi += carry */
291 "divl %%ecx \n\t" /* eax = u64Hi / u32C
292 edx = u64Hi % u32C */
293 "movl %%eax,%%edi \n\t" /* edi = u64Result.hi = u64Hi / u32C */
294 "movl %%esi,%%eax \n\t" /* eax = u64Lo.lo */
295 "divl %%ecx \n\t" /* u64Result.lo */
296 "movl %%edi,%%edx \n\t" /* u64Result.hi */
297 : "=A"(u64Result), "=c"(u32Dummy),
298 "=S"(u32Dummy), "=D"(u32Dummy)
299 : "a"((uint32_t)u64A),
300 "S"((uint32_t)(u64A >> 32)),
301 "c"(u32B),
302 "D"(u32C));
303 return u64Result;
304# endif
305# else
306 RTUINT64U u;
307 uint64_t u64Lo = (uint64_t)(u64A & 0xffffffff) * u32B;
308 uint64_t u64Hi = (uint64_t)(u64A >> 32) * u32B;
309 u64Hi += (u64Lo >> 32);
310 u.s.Hi = (uint32_t)(u64Hi / u32C);
311 u.s.Lo = (uint32_t)((((u64Hi % u32C) << 32) + (u64Lo & 0xffffffff)) / u32C);
312 return u.u;
313# endif
314}
315#endif
316
317/** @} */
318#endif
319
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