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add std.math f16 copysign support 

refs #1122
master
Ben Noordhuis 2018-06-30 01:44:54 +02:00
parent d293f1a0ed
commit ca444e6191
1 changed files with 18 additions and 0 deletions
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18
std/math/copysign.zig
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@ -4,12 +4,22 @@ const assert = std.debug.assert;
pub fn copysign(comptime T: type, x: T, y: T) T {
return switch (T) {
f16 => copysign16(x, y),
f32 => copysign32(x, y),
f64 => copysign64(x, y),
else => @compileError("copysign not implemented for " ++ @typeName(T)),
};
}
fn copysign16(x: f16, y: f16) f16 {
const ux = @bitCast(u16, x);
const uy = @bitCast(u16, y);
const h1 = ux & (@maxValue(u16) / 2);
const h2 = uy & (u16(1) << 15);
return @bitCast(f16, h1 | h2);
}
fn copysign32(x: f32, y: f32) f32 {
const ux = @bitCast(u32, x);
const uy = @bitCast(u32, y);
@ -29,10 +39,18 @@ fn copysign64(x: f64, y: f64) f64 {
}
test "math.copysign" {
assert(copysign(f16, 1.0, 1.0) == copysign16(1.0, 1.0));
assert(copysign(f32, 1.0, 1.0) == copysign32(1.0, 1.0));
assert(copysign(f64, 1.0, 1.0) == copysign64(1.0, 1.0));
}
test "math.copysign16" {
assert(copysign16(5.0, 1.0) == 5.0);
assert(copysign16(5.0, -1.0) == -5.0);
assert(copysign16(-5.0, -1.0) == -5.0);
assert(copysign16(-5.0, 1.0) == 5.0);
}
test "math.copysign32" {
assert(copysign32(5.0, 1.0) == 5.0);
assert(copysign32(5.0, -1.0) == -5.0);