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6bc6e47b15
Rather than lowering float negation as `0.0 - x`. * Add AIR instruction for float negation. * Add compiler-rt functions for f128, f80 negation closes #11853
24 lines
766 B
Zig
24 lines
766 B
Zig
const std = @import("../std.zig");
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const math = std.math;
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const expect = std.testing.expect;
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/// Returns whether x is negative or negative 0.
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pub fn signbit(x: anytype) bool {
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const T = @TypeOf(x);
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const TBits = std.meta.Int(.unsigned, @typeInfo(T).Float.bits);
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return @bitCast(TBits, x) >> (@bitSizeOf(T) - 1) != 0;
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}
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test "math.signbit" {
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inline for ([_]type{ f16, f32, f64, f80, f128 }) |T| {
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try expect(!signbit(@as(T, 0.0)));
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try expect(!signbit(@as(T, 1.0)));
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try expect(signbit(@as(T, -2.0)));
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try expect(signbit(@as(T, -0.0)));
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try expect(!signbit(math.inf(T)));
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try expect(signbit(-math.inf(T)));
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try expect(!signbit(math.nan(T)));
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try expect(signbit(-math.nan(T)));
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}
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}
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