pebble/src/libc/math/floor.c
2025-01-27 11:38:16 -08:00

57 lines
1.3 KiB
C

/*
* Copyright 2024 Google LLC
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
///////////////////////////////////////
// Implements:
// double floor(double x);
#include <pblibc_private.h>
#include <math.h>
#include <stdbool.h>
#include <stdint.h>
// TODO: PBL-36144 replace this naive implementation with __builtin_floor()
#ifndef NAN
#define NAN (0.0/0.0)
#endif
#ifndef INFINITY
#define INFINITY (1.0/0.0)
#endif
#ifndef isinf
#define isinf(y) (__builtin_isinf(y))
#endif
#ifndef isnan
#define isnan(y) (__builtin_isnan(y))
#endif
double floor(double x) {
if (isnan(x)) {
return NAN;
}
if (isinf(x)) {
return INFINITY;
}
const int64_t x_int = (int64_t)x;
const bool has_no_fraction = (double)x_int == x;
return (double)((x >= 0 || has_no_fraction) ? x_int : x_int - 1);
}