15c6d2ecb9c43d8b836b3203a243e24703d473765Stephen Canon//===-- lib/fp_lib.h - Floating-point utilities -------------------*- C -*-===// 25c6d2ecb9c43d8b836b3203a243e24703d473765Stephen Canon// 35c6d2ecb9c43d8b836b3203a243e24703d473765Stephen Canon// The LLVM Compiler Infrastructure 45c6d2ecb9c43d8b836b3203a243e24703d473765Stephen Canon// 59ad441ffec97db647fee3725b3424284fb913e14Howard Hinnant// This file is dual licensed under the MIT and the University of Illinois Open 69ad441ffec97db647fee3725b3424284fb913e14Howard Hinnant// Source Licenses. See LICENSE.TXT for details. 75c6d2ecb9c43d8b836b3203a243e24703d473765Stephen Canon// 85c6d2ecb9c43d8b836b3203a243e24703d473765Stephen Canon//===----------------------------------------------------------------------===// 95c6d2ecb9c43d8b836b3203a243e24703d473765Stephen Canon// 10e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon// This file is a configuration header for soft-float routines in compiler-rt. 115c6d2ecb9c43d8b836b3203a243e24703d473765Stephen Canon// This file does not provide any part of the compiler-rt interface, but defines 125c6d2ecb9c43d8b836b3203a243e24703d473765Stephen Canon// many useful constants and utility routines that are used in the 135c6d2ecb9c43d8b836b3203a243e24703d473765Stephen Canon// implementation of the soft-float routines in compiler-rt. 145c6d2ecb9c43d8b836b3203a243e24703d473765Stephen Canon// 15e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon// Assumes that float and double correspond to the IEEE-754 binary32 and 165c6d2ecb9c43d8b836b3203a243e24703d473765Stephen Canon// binary64 types, respectively, and that integer endianness matches floating 175c6d2ecb9c43d8b836b3203a243e24703d473765Stephen Canon// point endianness on the target platform. 185c6d2ecb9c43d8b836b3203a243e24703d473765Stephen Canon// 195c6d2ecb9c43d8b836b3203a243e24703d473765Stephen Canon//===----------------------------------------------------------------------===// 20e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon 21e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon#ifndef FP_LIB_HEADER 22e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon#define FP_LIB_HEADER 23e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon 24e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon#include <stdint.h> 25e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon#include <stdbool.h> 26e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon#include <limits.h> 270ae9d258a484ba5ede154f729660ad21bd0ade2eDaniel Dunbar#include "int_lib.h" 28e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon 29e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon#if defined SINGLE_PRECISION 30e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon 31e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canontypedef uint32_t rep_t; 32e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canontypedef int32_t srep_t; 33e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canontypedef float fp_t; 34e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon#define REP_C UINT32_C 35e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon#define significandBits 23 36e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon 37e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canonstatic inline int rep_clz(rep_t a) { 38e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon return __builtin_clz(a); 39e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon} 40e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon 4112a7d094b185795f478308f4fc27b43abebdde07Stephen Canon// 32x32 --> 64 bit multiply 4212a7d094b185795f478308f4fc27b43abebdde07Stephen Canonstatic inline void wideMultiply(rep_t a, rep_t b, rep_t *hi, rep_t *lo) { 4312a7d094b185795f478308f4fc27b43abebdde07Stephen Canon const uint64_t product = (uint64_t)a*b; 4412a7d094b185795f478308f4fc27b43abebdde07Stephen Canon *hi = product >> 32; 4512a7d094b185795f478308f4fc27b43abebdde07Stephen Canon *lo = product; 4612a7d094b185795f478308f4fc27b43abebdde07Stephen Canon} 4712a7d094b185795f478308f4fc27b43abebdde07Stephen Canon 48e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon#elif defined DOUBLE_PRECISION 49e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon 50e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canontypedef uint64_t rep_t; 51e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canontypedef int64_t srep_t; 52e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canontypedef double fp_t; 53e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon#define REP_C UINT64_C 54e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon#define significandBits 52 55e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon 56e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canonstatic inline int rep_clz(rep_t a) { 57e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon#if defined __LP64__ 58e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon return __builtin_clzl(a); 59e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon#else 60e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon if (a & REP_C(0xffffffff00000000)) 61c41370b2c334c673a95eda48e93c07b28dccd949Stephen Canon return __builtin_clz(a >> 32); 62e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon else 63c41370b2c334c673a95eda48e93c07b28dccd949Stephen Canon return 32 + __builtin_clz(a & REP_C(0xffffffff)); 64e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon#endif 65e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon} 66e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon 6712a7d094b185795f478308f4fc27b43abebdde07Stephen Canon#define loWord(a) (a & 0xffffffffU) 6812a7d094b185795f478308f4fc27b43abebdde07Stephen Canon#define hiWord(a) (a >> 32) 6912a7d094b185795f478308f4fc27b43abebdde07Stephen Canon 7012a7d094b185795f478308f4fc27b43abebdde07Stephen Canon// 64x64 -> 128 wide multiply for platforms that don't have such an operation; 7112a7d094b185795f478308f4fc27b43abebdde07Stephen Canon// many 64-bit platforms have this operation, but they tend to have hardware 7212a7d094b185795f478308f4fc27b43abebdde07Stephen Canon// floating-point, so we don't bother with a special case for them here. 7312a7d094b185795f478308f4fc27b43abebdde07Stephen Canonstatic inline void wideMultiply(rep_t a, rep_t b, rep_t *hi, rep_t *lo) { 7412a7d094b185795f478308f4fc27b43abebdde07Stephen Canon // Each of the component 32x32 -> 64 products 7512a7d094b185795f478308f4fc27b43abebdde07Stephen Canon const uint64_t plolo = loWord(a) * loWord(b); 7612a7d094b185795f478308f4fc27b43abebdde07Stephen Canon const uint64_t plohi = loWord(a) * hiWord(b); 7712a7d094b185795f478308f4fc27b43abebdde07Stephen Canon const uint64_t philo = hiWord(a) * loWord(b); 7812a7d094b185795f478308f4fc27b43abebdde07Stephen Canon const uint64_t phihi = hiWord(a) * hiWord(b); 7912a7d094b185795f478308f4fc27b43abebdde07Stephen Canon // Sum terms that contribute to lo in a way that allows us to get the carry 8012a7d094b185795f478308f4fc27b43abebdde07Stephen Canon const uint64_t r0 = loWord(plolo); 8112a7d094b185795f478308f4fc27b43abebdde07Stephen Canon const uint64_t r1 = hiWord(plolo) + loWord(plohi) + loWord(philo); 8212a7d094b185795f478308f4fc27b43abebdde07Stephen Canon *lo = r0 + (r1 << 32); 8312a7d094b185795f478308f4fc27b43abebdde07Stephen Canon // Sum terms contributing to hi with the carry from lo 8412a7d094b185795f478308f4fc27b43abebdde07Stephen Canon *hi = hiWord(plohi) + hiWord(philo) + hiWord(r1) + phihi; 8512a7d094b185795f478308f4fc27b43abebdde07Stephen Canon} 8612a7d094b185795f478308f4fc27b43abebdde07Stephen Canon 87e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon#else 88e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon#error Either SINGLE_PRECISION or DOUBLE_PRECISION must be defined. 89e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon#endif 90e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon 91e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon#define typeWidth (sizeof(rep_t)*CHAR_BIT) 92e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon#define exponentBits (typeWidth - significandBits - 1) 93e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon#define maxExponent ((1 << exponentBits) - 1) 94e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon#define exponentBias (maxExponent >> 1) 95e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon 96e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon#define implicitBit (REP_C(1) << significandBits) 97e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon#define significandMask (implicitBit - 1U) 98e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon#define signBit (REP_C(1) << (significandBits + exponentBits)) 99e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon#define absMask (signBit - 1U) 100e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon#define exponentMask (absMask ^ significandMask) 101e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon#define oneRep ((rep_t)exponentBias << significandBits) 102e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon#define infRep exponentMask 103e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon#define quietBit (implicitBit >> 1) 104e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon#define qnanRep (exponentMask | quietBit) 105e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon 106e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canonstatic inline rep_t toRep(fp_t x) { 107e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon const union { fp_t f; rep_t i; } rep = {.f = x}; 108e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon return rep.i; 109e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon} 110e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon 111e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canonstatic inline fp_t fromRep(rep_t x) { 112e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon const union { fp_t f; rep_t i; } rep = {.i = x}; 113e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon return rep.f; 114e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon} 115e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon 116e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canonstatic inline int normalize(rep_t *significand) { 117e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon const int shift = rep_clz(*significand) - rep_clz(implicitBit); 118e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon *significand <<= shift; 119e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon return 1 - shift; 120e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon} 121e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon 122e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canonstatic inline void wideLeftShift(rep_t *hi, rep_t *lo, int count) { 123e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon *hi = *hi << count | *lo >> (typeWidth - count); 124e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon *lo = *lo << count; 125e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon} 126e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon 1270499b8433538a1913ca955566cd34368752bf7afJoerg Sonnenbergerstatic inline void wideRightShiftWithSticky(rep_t *hi, rep_t *lo, unsigned int count) { 128e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon if (count < typeWidth) { 129e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon const bool sticky = *lo << (typeWidth - count); 130e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon *lo = *hi << (typeWidth - count) | *lo >> count | sticky; 131e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon *hi = *hi >> count; 132e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon } 133e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon else if (count < 2*typeWidth) { 134e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon const bool sticky = *hi << (2*typeWidth - count) | *lo; 135e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon *lo = *hi >> (count - typeWidth) | sticky; 136e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon *hi = 0; 137e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon } else { 138e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon const bool sticky = *hi | *lo; 139e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon *lo = sticky; 140e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon *hi = 0; 141e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon } 142e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon} 143e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon 144e5086322295e5a345af02d09abfcf8ddca2d0897Stephen Canon#endif // FP_LIB_HEADER 145