forked from OSchip/llvm-project
117 lines
3.5 KiB
C
117 lines
3.5 KiB
C
//===-- lib/fp_compare_impl.inc - Floating-point comparison -------*- 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
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#include "fp_lib.h"
|
|
|
|
// GCC uses long (at least for x86_64) as the return type of the comparison
|
|
// functions. We need to ensure that the return value is sign-extended in the
|
|
// same way as GCC expects (since otherwise GCC-generated __builtin_isinf
|
|
// returns true for finite 128-bit floating-point numbers).
|
|
#ifdef __aarch64__
|
|
// AArch64 GCC overrides libgcc_cmp_return to use int instead of long.
|
|
typedef int CMP_RESULT;
|
|
#elif __SIZEOF_POINTER__ == 8 && __SIZEOF_LONG__ == 4
|
|
// LLP64 ABIs use long long instead of long.
|
|
typedef long long CMP_RESULT;
|
|
#else
|
|
// Otherwise the comparison functions return long.
|
|
typedef long CMP_RESULT;
|
|
#endif
|
|
|
|
#if !defined(__clang__) && defined(__GNUC__)
|
|
// GCC uses a special __libgcc_cmp_return__ mode to define the return type, so
|
|
// check that we are ABI-compatible when compiling the builtins with GCC.
|
|
typedef int GCC_CMP_RESULT __attribute__((__mode__(__libgcc_cmp_return__)));
|
|
_Static_assert(sizeof(GCC_CMP_RESULT) == sizeof(CMP_RESULT),
|
|
"SOFTFP ABI not compatible with GCC");
|
|
#endif
|
|
|
|
enum {
|
|
LE_LESS = -1,
|
|
LE_EQUAL = 0,
|
|
LE_GREATER = 1,
|
|
LE_UNORDERED = 1,
|
|
};
|
|
|
|
static inline CMP_RESULT __leXf2__(fp_t a, fp_t b) {
|
|
const srep_t aInt = toRep(a);
|
|
const srep_t bInt = toRep(b);
|
|
const rep_t aAbs = aInt & absMask;
|
|
const rep_t bAbs = bInt & absMask;
|
|
|
|
// If either a or b is NaN, they are unordered.
|
|
if (aAbs > infRep || bAbs > infRep)
|
|
return LE_UNORDERED;
|
|
|
|
// If a and b are both zeros, they are equal.
|
|
if ((aAbs | bAbs) == 0)
|
|
return LE_EQUAL;
|
|
|
|
// If at least one of a and b is positive, we get the same result comparing
|
|
// a and b as signed integers as we would with a floating-point compare.
|
|
if ((aInt & bInt) >= 0) {
|
|
if (aInt < bInt)
|
|
return LE_LESS;
|
|
else if (aInt == bInt)
|
|
return LE_EQUAL;
|
|
else
|
|
return LE_GREATER;
|
|
} else {
|
|
// Otherwise, both are negative, so we need to flip the sense of the
|
|
// comparison to get the correct result. (This assumes a twos- or ones-
|
|
// complement integer representation; if integers are represented in a
|
|
// sign-magnitude representation, then this flip is incorrect).
|
|
if (aInt > bInt)
|
|
return LE_LESS;
|
|
else if (aInt == bInt)
|
|
return LE_EQUAL;
|
|
else
|
|
return LE_GREATER;
|
|
}
|
|
}
|
|
|
|
enum {
|
|
GE_LESS = -1,
|
|
GE_EQUAL = 0,
|
|
GE_GREATER = 1,
|
|
GE_UNORDERED = -1 // Note: different from LE_UNORDERED
|
|
};
|
|
|
|
static inline CMP_RESULT __geXf2__(fp_t a, fp_t b) {
|
|
const srep_t aInt = toRep(a);
|
|
const srep_t bInt = toRep(b);
|
|
const rep_t aAbs = aInt & absMask;
|
|
const rep_t bAbs = bInt & absMask;
|
|
|
|
if (aAbs > infRep || bAbs > infRep)
|
|
return GE_UNORDERED;
|
|
if ((aAbs | bAbs) == 0)
|
|
return GE_EQUAL;
|
|
if ((aInt & bInt) >= 0) {
|
|
if (aInt < bInt)
|
|
return GE_LESS;
|
|
else if (aInt == bInt)
|
|
return GE_EQUAL;
|
|
else
|
|
return GE_GREATER;
|
|
} else {
|
|
if (aInt > bInt)
|
|
return GE_LESS;
|
|
else if (aInt == bInt)
|
|
return GE_EQUAL;
|
|
else
|
|
return GE_GREATER;
|
|
}
|
|
}
|
|
|
|
static inline CMP_RESULT __unordXf2__(fp_t a, fp_t b) {
|
|
const rep_t aAbs = toRep(a) & absMask;
|
|
const rep_t bAbs = toRep(b) & absMask;
|
|
return aAbs > infRep || bAbs > infRep;
|
|
}
|