2017-06-16 16:26:10 +08:00
|
|
|
const math = @import("index.zig");
|
2017-06-08 10:56:57 +08:00
|
|
|
const assert = @import("../debug.zig").assert;
|
|
|
|
|
|
|
|
pub fn fabs(x: var) -> @typeOf(x) {
|
|
|
|
const T = @typeOf(x);
|
|
|
|
switch (T) {
|
2017-06-16 16:26:10 +08:00
|
|
|
f32 => @inlineCall(fabs32, x),
|
|
|
|
f64 => @inlineCall(fabs64, x),
|
2017-06-08 10:56:57 +08:00
|
|
|
else => @compileError("fabs not implemented for " ++ @typeName(T)),
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
fn fabs32(x: f32) -> f32 {
|
|
|
|
var u = @bitCast(u32, x);
|
|
|
|
u &= 0x7FFFFFFF;
|
|
|
|
@bitCast(f32, u)
|
|
|
|
}
|
|
|
|
|
|
|
|
fn fabs64(x: f64) -> f64 {
|
|
|
|
var u = @bitCast(u64, x);
|
|
|
|
u &= @maxValue(u64) >> 1;
|
|
|
|
@bitCast(f64, u)
|
|
|
|
}
|
|
|
|
|
|
|
|
test "fabs" {
|
|
|
|
assert(fabs(f32(1.0)) == fabs32(1.0));
|
|
|
|
assert(fabs(f64(1.0)) == fabs64(1.0));
|
|
|
|
}
|
|
|
|
|
|
|
|
test "fabs32" {
|
|
|
|
assert(fabs64(1.0) == 1.0);
|
|
|
|
assert(fabs64(-1.0) == 1.0);
|
|
|
|
}
|
|
|
|
|
|
|
|
test "fabs64" {
|
|
|
|
assert(fabs64(1.0) == 1.0);
|
|
|
|
assert(fabs64(-1.0) == 1.0);
|
|
|
|
}
|