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minoki/test-fma.c

Last active Aug 12, 2020
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A test program to check if your compiler's fma() is implemented correctly
#include <math.h>
#include <stdbool.h>
#include <stdio.h>
struct fma_test_case_d
{
double a, b, c, expected;
} static const cases_d[] = {
{0x1p1000, 0x1p1000, -INFINITY, -INFINITY},
{-0x1.4f8ac19291ffap1023, 0x1.39c33c8d39b7p-1025, 0x1.ee11f685e2e12p-1, 0x1.2071b0283f156p-1},
{0x1.0000000000008p500, 0x1.1p500, 0x1p-1074, 0x1.1000000000009p1000},
{0x1.0000000000001p500, 0x1.8p500, -0x1p-1074, 0x1.8000000000001p1000},
{0x0.ffffffep513, 0x1.0000002p511, -0x1p-1074, 0x1.fffffffffffffp1023},
};
struct fma_test_case_f
{
float a, b, c, expected;
} static const cases_f[] = {
{0x1p100f, 0x1p100f, -INFINITY, -INFINITY},
{0x1.fffffep23f, 0x1.000004p28f, 0x1.fcp5f, 0x1.000002p52f},
{0x1.84ae3p125f, 0x1.6p-141f, 0x1p-149f, 0x1.0b37c2p-15f},
{0x1.00001p50f, 0x1.1p50f, 0x1p-149f, 0x1.100012p100f},
{0x1.000002p50f, 0x1.8p50f, -0x1p-149f, 0x1.800002p100f},
{0x1.83bd78p4f, -0x1.cp118f, -0x1.344108p-2f, -0x1.5345cap123f},
};
int main(void)
{
#if defined(FP_FAST_FMA)
puts("FP_FAST_FMA is defined.");
#endif
#if defined(FP_FAST_FMAF)
puts("FP_FAST_FMAF is defined.");
#endif
#if defined(__FMA__)
puts("__FMA__ is defined.");
#endif
#if defined(__FMA4__)
puts("__FMA4__ is defined.");
#endif
{
bool all_tests_passed = true;
for (size_t i = 0; i < sizeof(cases_d) / sizeof(cases_d[0]); ++i) {
double a = cases_d[i].a;
double b = cases_d[i].b;
double c = cases_d[i].c;
double expected = cases_d[i].expected;
double result = fma(a, b, c);
bool same = isnan(expected) ? isnan(result) : expected == result && signbit(expected) == signbit(result);
if (!same) {
all_tests_passed = false;
printf("fma(%a, %a, %a): Expected %a, but got %a.\n", a, b, c, expected, result);
}
}
if (all_tests_passed) {
puts("All tests passed for fma(double, double, double).");
}
}
{
bool all_tests_passed = true;
for (size_t i = 0; i < sizeof(cases_f) / sizeof(cases_f[0]); ++i) {
float a = cases_f[i].a;
float b = cases_f[i].b;
float c = cases_f[i].c;
float expected = cases_f[i].expected;
float result = fmaf(a, b, c);
bool same = isnan(expected) ? isnan(result) : expected == result && signbit(expected) == signbit(result);
if (!same) {
all_tests_passed = false;
printf("fmaf(%a, %a, %a): Expected %a, but got %a.\n", a, b, c, expected, result);
}
}
if (all_tests_passed) {
puts("All tests passed for fmaf(float, float, float).");
}
}
}
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