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1//===-- lib/fp_compare_impl.inc - Floating-point comparison -------*- C -*-===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8 9#include "fp_lib.h"10 11// GCC uses long (at least for x86_64) as the return type of the comparison12// functions. We need to ensure that the return value is sign-extended in the13// same way as GCC expects (since otherwise GCC-generated __builtin_isinf14// returns true for finite 128-bit floating-point numbers).15#if defined(__aarch64__) || defined(__arm64ec__)16// AArch64 GCC overrides libgcc_cmp_return to use int instead of long.17typedef int CMP_RESULT;18#elif __SIZEOF_POINTER__ == 8 && __SIZEOF_LONG__ == 419// LLP64 ABIs use long long instead of long.20typedef long long CMP_RESULT;21#elif __AVR__22// AVR uses a single byte for the return value.23typedef char CMP_RESULT;24#else25// Otherwise the comparison functions return long.26typedef long CMP_RESULT;27#endif28 29#if !defined(__clang__) && defined(__GNUC__)30// GCC uses a special __libgcc_cmp_return__ mode to define the return type, so31// check that we are ABI-compatible when compiling the builtins with GCC.32typedef int GCC_CMP_RESULT __attribute__((__mode__(__libgcc_cmp_return__)));33_Static_assert(sizeof(GCC_CMP_RESULT) == sizeof(CMP_RESULT),34 "SOFTFP ABI not compatible with GCC");35#endif36 37enum {38 LE_LESS = -1,39 LE_EQUAL = 0,40 LE_GREATER = 1,41 LE_UNORDERED = 1,42};43 44static inline CMP_RESULT __leXf2__(fp_t a, fp_t b) {45 const srep_t aInt = toRep(a);46 const srep_t bInt = toRep(b);47 const rep_t aAbs = aInt & absMask;48 const rep_t bAbs = bInt & absMask;49 50 // If either a or b is NaN, they are unordered.51 if (aAbs > infRep || bAbs > infRep)52 return LE_UNORDERED;53 54 // If a and b are both zeros, they are equal.55 if ((aAbs | bAbs) == 0)56 return LE_EQUAL;57 58 // If at least one of a and b is positive, we get the same result comparing59 // a and b as signed integers as we would with a floating-point compare.60 if ((aInt & bInt) >= 0) {61 if (aInt < bInt)62 return LE_LESS;63 else if (aInt == bInt)64 return LE_EQUAL;65 else66 return LE_GREATER;67 } else {68 // Otherwise, both are negative, so we need to flip the sense of the69 // comparison to get the correct result. (This assumes a twos- or ones-70 // complement integer representation; if integers are represented in a71 // sign-magnitude representation, then this flip is incorrect).72 if (aInt > bInt)73 return LE_LESS;74 else if (aInt == bInt)75 return LE_EQUAL;76 else77 return LE_GREATER;78 }79}80 81enum {82 GE_LESS = -1,83 GE_EQUAL = 0,84 GE_GREATER = 1,85 GE_UNORDERED = -1 // Note: different from LE_UNORDERED86};87 88static inline CMP_RESULT __geXf2__(fp_t a, fp_t b) {89 const srep_t aInt = toRep(a);90 const srep_t bInt = toRep(b);91 const rep_t aAbs = aInt & absMask;92 const rep_t bAbs = bInt & absMask;93 94 if (aAbs > infRep || bAbs > infRep)95 return GE_UNORDERED;96 if ((aAbs | bAbs) == 0)97 return GE_EQUAL;98 if ((aInt & bInt) >= 0) {99 if (aInt < bInt)100 return GE_LESS;101 else if (aInt == bInt)102 return GE_EQUAL;103 else104 return GE_GREATER;105 } else {106 if (aInt > bInt)107 return GE_LESS;108 else if (aInt == bInt)109 return GE_EQUAL;110 else111 return GE_GREATER;112 }113}114 115static inline CMP_RESULT __unordXf2__(fp_t a, fp_t b) {116 const rep_t aAbs = toRep(a) & absMask;117 const rep_t bAbs = toRep(b) & absMask;118 return aAbs > infRep || bAbs > infRep;119}120