56 lines
1.2 KiB
Zig
56 lines
1.2 KiB
Zig
// Special Cases:
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//
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// - fabs(+-inf) = +inf
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// - fabs(nan) = nan
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const math = @import("index.zig");
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const assert = @import("../debug.zig").assert;
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pub fn fabs(x: var) -> @typeOf(x) {
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const T = @typeOf(x);
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switch (T) {
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f32 => @inlineCall(fabs32, x),
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f64 => @inlineCall(fabs64, x),
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else => @compileError("fabs not implemented for " ++ @typeName(T)),
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}
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}
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fn fabs32(x: f32) -> f32 {
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var u = @bitCast(u32, x);
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u &= 0x7FFFFFFF;
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@bitCast(f32, u)
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}
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fn fabs64(x: f64) -> f64 {
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var u = @bitCast(u64, x);
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u &= @maxValue(u64) >> 1;
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@bitCast(f64, u)
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}
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test "math.fabs" {
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assert(fabs(f32(1.0)) == fabs32(1.0));
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assert(fabs(f64(1.0)) == fabs64(1.0));
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}
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test "math.fabs32" {
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assert(fabs32(1.0) == 1.0);
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assert(fabs32(-1.0) == 1.0);
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}
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test "math.fabs64" {
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assert(fabs64(1.0) == 1.0);
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assert(fabs64(-1.0) == 1.0);
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}
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test "math.fabs32.special" {
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assert(math.isPositiveInf(fabs(math.inf(f32))));
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assert(math.isPositiveInf(fabs(-math.inf(f32))));
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assert(math.isNan(fabs(math.nan(f32))));
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}
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test "math.fabs64.special" {
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assert(math.isPositiveInf(fabs(math.inf(f64))));
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assert(math.isPositiveInf(fabs(-math.inf(f64))));
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assert(math.isNan(fabs(math.nan(f64))));
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}
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