//===-- lib/fp_lib.h - Floating-point utilities -------------------*- C -*-===// // // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. // See https://llvm.org/LICENSE.txt for license information. // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception // //===----------------------------------------------------------------------===// // // This file is a configuration header for soft-float routines in compiler-rt. // This file does not provide any part of the compiler-rt interface, but defines // many useful constants and utility routines that are used in the // implementation of the soft-float routines in compiler-rt. // // Assumes that float, double and long double correspond to the IEEE-754 // binary32, binary64 and binary 128 types, respectively, and that integer // endianness matches floating point endianness on the target platform. // //===----------------------------------------------------------------------===// #ifndef FP_LIB_HEADER #define FP_LIB_HEADER #include "int_lib.h" #include "int_math.h" #include "int_types.h" #include <limits.h> #include <stdbool.h> #include <stdint.h> #if defined SINGLE_PRECISION half_rep_t; rep_t; twice_rep_t; srep_t; fp_t; #define HALF_REP_C … #define REP_C … #define significandBits … static __inline int rep_clz(rep_t a) { … } // 32x32 --> 64 bit multiply static __inline void wideMultiply(rep_t a, rep_t b, rep_t *hi, rep_t *lo) { … } COMPILER_RT_ABI fp_t __addsf3(fp_t a, fp_t b); #elif defined DOUBLE_PRECISION typedef uint32_t half_rep_t; typedef uint64_t rep_t; typedef int64_t srep_t; typedef double fp_t; #define HALF_REP_C … #define REP_C … #define significandBits … static inline int rep_clz(rep_t a) { return __builtin_clzll(a); } #define loWord … #define hiWord … // 64x64 -> 128 wide multiply for platforms that don't have such an operation; // many 64-bit platforms have this operation, but they tend to have hardware // floating-point, so we don't bother with a special case for them here. static __inline void wideMultiply(rep_t a, rep_t b, rep_t *hi, rep_t *lo) { // Each of the component 32x32 -> 64 products const uint64_t plolo = loWord(a) * loWord(b); const uint64_t plohi = loWord(a) * hiWord(b); const uint64_t philo = hiWord(a) * loWord(b); const uint64_t phihi = hiWord(a) * hiWord(b); // Sum terms that contribute to lo in a way that allows us to get the carry const uint64_t r0 = loWord(plolo); const uint64_t r1 = hiWord(plolo) + loWord(plohi) + loWord(philo); *lo = r0 + (r1 << 32); // Sum terms contributing to hi with the carry from lo *hi = hiWord(plohi) + hiWord(philo) + hiWord(r1) + phihi; } #undef loWord #undef hiWord COMPILER_RT_ABI fp_t __adddf3(fp_t a, fp_t b); #elif defined QUAD_PRECISION #if defined(CRT_HAS_F128) && defined(CRT_HAS_128BIT) typedef uint64_t half_rep_t; typedef __uint128_t rep_t; typedef __int128_t srep_t; typedef tf_float fp_t; #define HALF_REP_C … #define REP_C … #if defined(CRT_HAS_IEEE_TF) // Note: Since there is no explicit way to tell compiler the constant is a // 128-bit integer, we let the constant be casted to 128-bit integer #define significandBits … #define TF_MANT_DIG … static __inline int rep_clz(rep_t a) { const union { __uint128_t ll; #if _YUGA_BIG_ENDIAN struct { uint64_t high, low; } s; #else struct { uint64_t low, high; } s; #endif } uu = {.ll = a}; uint64_t word; uint64_t add; if (uu.s.high) { word = uu.s.high; add = 0; } else { word = uu.s.low; add = 64; } return __builtin_clzll(word) + add; } #define Word_LoMask … #define Word_HiMask … #define Word_FullMask … #define Word_1 … #define Word_2 … #define Word_3 … #define Word_4 … // 128x128 -> 256 wide multiply for platforms that don't have such an operation; // many 64-bit platforms have this operation, but they tend to have hardware // floating-point, so we don't bother with a special case for them here. static __inline void wideMultiply(rep_t a, rep_t b, rep_t *hi, rep_t *lo) { const uint64_t product11 = Word_1(a) * Word_1(b); const uint64_t product12 = Word_1(a) * Word_2(b); const uint64_t product13 = Word_1(a) * Word_3(b); const uint64_t product14 = Word_1(a) * Word_4(b); const uint64_t product21 = Word_2(a) * Word_1(b); const uint64_t product22 = Word_2(a) * Word_2(b); const uint64_t product23 = Word_2(a) * Word_3(b); const uint64_t product24 = Word_2(a) * Word_4(b); const uint64_t product31 = Word_3(a) * Word_1(b); const uint64_t product32 = Word_3(a) * Word_2(b); const uint64_t product33 = Word_3(a) * Word_3(b); const uint64_t product34 = Word_3(a) * Word_4(b); const uint64_t product41 = Word_4(a) * Word_1(b); const uint64_t product42 = Word_4(a) * Word_2(b); const uint64_t product43 = Word_4(a) * Word_3(b); const uint64_t product44 = Word_4(a) * Word_4(b); const __uint128_t sum0 = (__uint128_t)product44; const __uint128_t sum1 = (__uint128_t)product34 + (__uint128_t)product43; const __uint128_t sum2 = (__uint128_t)product24 + (__uint128_t)product33 + (__uint128_t)product42; const __uint128_t sum3 = (__uint128_t)product14 + (__uint128_t)product23 + (__uint128_t)product32 + (__uint128_t)product41; const __uint128_t sum4 = (__uint128_t)product13 + (__uint128_t)product22 + (__uint128_t)product31; const __uint128_t sum5 = (__uint128_t)product12 + (__uint128_t)product21; const __uint128_t sum6 = (__uint128_t)product11; const __uint128_t r0 = (sum0 & Word_FullMask) + ((sum1 & Word_LoMask) << 32); const __uint128_t r1 = (sum0 >> 64) + ((sum1 >> 32) & Word_FullMask) + (sum2 & Word_FullMask) + ((sum3 << 32) & Word_HiMask); *lo = r0 + (r1 << 64); // The addition above can overflow, in which case `*lo` will be less than // `r0`. Carry any overflow into `hi`. const bool carry = *lo < r0; *hi = (r1 >> 64) + (sum1 >> 96) + (sum2 >> 64) + (sum3 >> 32) + sum4 + (sum5 << 32) + (sum6 << 64) + carry; } #undef Word_1 #undef Word_2 #undef Word_3 #undef Word_4 #undef Word_HiMask #undef Word_LoMask #undef Word_FullMask #endif // defined(CRT_HAS_IEEE_TF) #else typedef long double fp_t; #endif // defined(CRT_HAS_F128) && defined(CRT_HAS_128BIT) #else #error SINGLE_PRECISION, DOUBLE_PRECISION or QUAD_PRECISION must be defined. #endif #if defined(SINGLE_PRECISION) || defined(DOUBLE_PRECISION) || \ (defined(QUAD_PRECISION) && defined(CRT_HAS_TF_MODE)) #define typeWidth … static __inline rep_t toRep(fp_t x) { … } static __inline fp_t fromRep(rep_t x) { … } #if !defined(QUAD_PRECISION) || defined(CRT_HAS_IEEE_TF) #define exponentBits … #define maxExponent … #define exponentBias … #define implicitBit … #define significandMask … #define signBit … #define absMask … #define exponentMask … #define oneRep … #define infRep … #define quietBit … #define qnanRep … static __inline int normalize(rep_t *significand) { … } static __inline void wideLeftShift(rep_t *hi, rep_t *lo, unsigned int count) { … } static __inline void wideRightShiftWithSticky(rep_t *hi, rep_t *lo, unsigned int count) { … } // Implements logb methods (logb, logbf, logbl) for IEEE-754. This avoids // pulling in a libm dependency from compiler-rt, but is not meant to replace // it (i.e. code calling logb() should get the one from libm, not this), hence // the __compiler_rt prefix. static __inline fp_t __compiler_rt_logbX(fp_t x) { … } // Avoid using scalbn from libm. Unlike libc/libm scalbn, this function never // sets errno on underflow/overflow. static __inline fp_t __compiler_rt_scalbnX(fp_t x, int y) { … } #endif // !defined(QUAD_PRECISION) || defined(CRT_HAS_IEEE_TF) // Avoid using fmax from libm. static __inline fp_t __compiler_rt_fmaxX(fp_t x, fp_t y) { … } #endif #if defined(SINGLE_PRECISION) static __inline fp_t __compiler_rt_logbf(fp_t x) { … } static __inline fp_t __compiler_rt_scalbnf(fp_t x, int y) { … } #elif defined(DOUBLE_PRECISION) static __inline fp_t __compiler_rt_logb(fp_t x) { return __compiler_rt_logbX(x); } static __inline fp_t __compiler_rt_scalbn(fp_t x, int y) { return __compiler_rt_scalbnX(x, y); } static __inline fp_t __compiler_rt_fmax(fp_t x, fp_t y) { #if defined(__aarch64__) // Use __builtin_fmax which turns into an fmaxnm instruction on AArch64. return __builtin_fmax(x, y); #else // __builtin_fmax frequently turns into a libm call, so inline the function. return __compiler_rt_fmaxX(x, y); #endif } #elif defined(QUAD_PRECISION) && defined(CRT_HAS_TF_MODE) // The generic implementation only works for ieee754 floating point. For other // floating point types, continue to rely on the libm implementation for now. #if defined(CRT_HAS_IEEE_TF) static __inline tf_float __compiler_rt_logbtf(tf_float x) { return __compiler_rt_logbX(x); } static __inline tf_float __compiler_rt_scalbntf(tf_float x, int y) { return __compiler_rt_scalbnX(x, y); } static __inline tf_float __compiler_rt_fmaxtf(tf_float x, tf_float y) { return __compiler_rt_fmaxX(x, y); } #define __compiler_rt_logbl … #define __compiler_rt_scalbnl … #define __compiler_rt_fmaxl … #define crt_fabstf … #define crt_copysigntf … #elif defined(CRT_LDBL_128BIT) static __inline tf_float __compiler_rt_logbtf(tf_float x) { return crt_logbl(x); } static __inline tf_float __compiler_rt_scalbntf(tf_float x, int y) { return crt_scalbnl(x, y); } static __inline tf_float __compiler_rt_fmaxtf(tf_float x, tf_float y) { return crt_fmaxl(x, y); } #define __compiler_rt_logbl … #define __compiler_rt_scalbnl … #define __compiler_rt_fmaxl … #define crt_fabstf … #define crt_copysigntf … #else #error Unsupported TF mode type #endif #endif // *_PRECISION #endif // FP_LIB_HEADER
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