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// gcc -Wall -W -lm double-to-float-with-rounding-modes.c -o double-to-float-with-rounding-modes -frounding-math -fsignaling-nans -ffp-contract=off -msse2 -mfpmath=sse
#ifdef __GNUC__
#include <assert.h>
#include <fenv.h>
#include <math.h>
float setRoundingModeAndCast(int mode, double d) {
fesetround(mode);
return (float)d;
}
void test (int mode, double d, float result) {
float f = setRoundingModeAndCast(mode,d);
assert(f == result);
return;
}
#endif
int main (void)
{
#ifdef __GNUC__
// 0x1.fffffep+127f is the largest binary32 float so
// these should all be representable as floats...
test(FE_TONEAREST, 0x1.fffffep+127, 0x1.fffffep+127);
#ifdef FE_UPWARD
test(FE_UPWARD, 0x1.fffffep+127, 0x1.fffffep+127);
#endif
#ifdef FE_DOWNWARD
test(FE_DOWNWARD, 0x1.fffffep+127, 0x1.fffffep+127);
#endif
test(FE_TOWARDZERO, 0x1.fffffep+127, 0x1.fffffep+127);
// Likewise, this should be an obvious sanity check
test(FE_TONEAREST, +INFINITY, +INFINITY);
#ifdef FE_UPWARD
test(FE_UPWARD, +INFINITY, +INFINITY);
#endif
#ifdef FE_DOWNWARD
test(FE_DOWNWARD, +INFINITY, +INFINITY);
#endif
test(FE_TOWARDZERO, +INFINITY, +INFINITY);
// Nearer to 0x1.fffffep+127 than to 0x1.000000p+128
test(FE_TONEAREST, 0x1.fffffe0000001p+127, 0x1.fffffep+127);
#ifdef FE_UPWARD
test(FE_UPWARD, 0x1.fffffe0000001p+127, +INFINITY);
#endif
#ifdef FE_DOWNWARD
test(FE_DOWNWARD, 0x1.fffffe0000001p+127, 0x1.fffffep+127);
#endif
test(FE_TOWARDZERO, 0x1.fffffe0000001p+127, 0x1.fffffep+127);
// 0x1.fffffefffffffp+127 is immediately below half way
test(FE_TONEAREST, 0x1.fffffefffffffp+127, 0x1.fffffep+127);
#ifdef FE_UPWARD
test(FE_UPWARD, 0x1.fffffefffffffp+127, +INFINITY);
#endif
#ifdef FE_DOWNWARD
test(FE_DOWNWARD, 0x1.fffffefffffffp+127, 0x1.fffffep+127);
#endif
test(FE_TOWARDZERO, 0x1.fffffefffffffp+127, 0x1.fffffep+127);
// Half way
test(FE_TONEAREST, 0x1.ffffffp+127, +INFINITY);
#ifdef FE_UPWARD
test(FE_UPWARD, 0x1.ffffffp+127, +INFINITY);
#endif
#ifdef FE_DOWNWARD
test(FE_DOWNWARD, 0x1.ffffffp+127, 0x1.fffffep+127);
#endif
test(FE_TOWARDZERO, 0x1.ffffffp+127, 0x1.fffffep+127);
// Larger
test(FE_TONEAREST, 0x1.0p+128, +INFINITY);
#ifdef FE_UPWARD
test(FE_UPWARD, 0x1.0p+128, +INFINITY);
#endif
#ifdef FE_DOWNWARD
test(FE_DOWNWARD, 0x1.0p+128, 0x1.fffffep+127);
#endif
test(FE_TOWARDZERO, 0x1.0p+128, 0x1.fffffep+127);
// Huge
test(FE_TONEAREST, 0x1.fffffffffffffp+1023, +INFINITY);
#ifdef FE_UPWARD
test(FE_UPWARD, 0x1.fffffffffffffp+1023, +INFINITY);
#endif
#ifdef FE_DOWNWARD
test(FE_DOWNWARD, 0x1.fffffffffffffp+1023, 0x1.fffffep+127);
#endif
test(FE_TOWARDZERO, 0x1.fffffffffffffp+1023, 0x1.fffffep+127);
// Same again but negative
test(FE_TONEAREST, -0x1.fffffep+127, -0x1.fffffep+127);
#ifdef FE_UPWARD
test(FE_UPWARD, -0x1.fffffep+127, -0x1.fffffep+127);
#endif
#ifdef FE_DOWNWARD
test(FE_DOWNWARD, -0x1.fffffep+127, -0x1.fffffep+127);
#endif
test(FE_TOWARDZERO, -0x1.fffffep+127, -0x1.fffffep+127);
test(FE_TONEAREST, -INFINITY, -INFINITY);
#ifdef FE_UPWARD
test(FE_UPWARD, -INFINITY, -INFINITY);
#endif
#ifdef FE_DOWNWARD
test(FE_DOWNWARD, -INFINITY, -INFINITY);
#endif
test(FE_TOWARDZERO, -INFINITY, -INFINITY);
test(FE_TONEAREST, -0x1.fffffe0000001p+127, -0x1.fffffep+127);
#ifdef FE_UPWARD
test(FE_UPWARD, -0x1.fffffe0000001p+127, -0x1.fffffep+127);
#endif
#ifdef FE_DOWNWARD
test(FE_DOWNWARD, -0x1.fffffe0000001p+127, -INFINITY);
#endif
test(FE_TOWARDZERO, -0x1.fffffe0000001p+127, -0x1.fffffep+127);
test(FE_TONEAREST, -0x1.fffffefffffffp+127, -0x1.fffffep+127);
#ifdef FE_UPWARD
test(FE_UPWARD, -0x1.fffffefffffffp+127, -0x1.fffffep+127);
#endif
#ifdef FE_DOWNWARD
test(FE_DOWNWARD, -0x1.fffffefffffffp+127, -INFINITY);
#endif
test(FE_TOWARDZERO, -0x1.fffffefffffffp+127, -0x1.fffffep+127);
test(FE_TONEAREST, -0x1.ffffffp+127, -INFINITY);
#ifdef FE_UPWARD
test(FE_UPWARD, -0x1.ffffffp+127, -0x1.fffffep+127);
#endif
#ifdef FE_DOWNWARD
test(FE_DOWNWARD, -0x1.ffffffp+127, -INFINITY);
#endif
test(FE_TOWARDZERO, -0x1.ffffffp+127, -0x1.fffffep+127);
test(FE_TONEAREST, -0x1.0p+128, -INFINITY);
#ifdef FE_UPWARD
test(FE_UPWARD, -0x1.0p+128, -0x1.fffffep+127);
#endif
#ifdef FE_DOWNWARD
test(FE_DOWNWARD, -0x1.0p+128, -INFINITY);
#endif
test(FE_TOWARDZERO, -0x1.0p+128, -0x1.fffffep+127);
test(FE_TONEAREST, -0x1.fffffffffffffp+1023, -INFINITY);
#ifdef FE_UPWARD
test(FE_UPWARD, -0x1.fffffffffffffp+1023, -0x1.fffffep+127);
#endif
#ifdef FE_DOWNWARD
test(FE_DOWNWARD, -0x1.fffffffffffffp+1023, -INFINITY);
#endif
test(FE_TOWARDZERO, -0x1.fffffffffffffp+1023, -0x1.fffffep+127);
#endif
return 1;
}
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