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std.math.is*Inf: make generic, support f80

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viri 2022-04-07 03:08:42 -06:00
parent c5c6260534
commit 5d6a5a1236
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GPG Key ID: 70D2D3DF8F7FB7C3
1 changed files with 34 additions and 105 deletions
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139
lib/std/math/isinf.zig
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@ -1,131 +1,60 @@
const std = @import("../std.zig");
const math = std.math;
const expect = std.testing.expect;
const maxInt = std.math.maxInt;
/// Returns whether x is an infinity, ignoring sign.
pub fn isInf(x: anytype) bool {
const T = @TypeOf(x);
switch (T) {
f16 => {
const bits = @bitCast(u16, x);
return bits & 0x7FFF == 0x7C00;
},
f32 => {
const bits = @bitCast(u32, x);
return bits & 0x7FFFFFFF == 0x7F800000;
},
f64 => {
const bits = @bitCast(u64, x);
return bits & (maxInt(u64) >> 1) == (0x7FF << 52);
},
f128 => {
const bits = @bitCast(u128, x);
return bits & (maxInt(u128) >> 1) == (0x7FFF << 112);
},
else => {
@compileError("isInf not implemented for " ++ @typeName(T));
},
const TBits = std.meta.Int(.unsigned, @bitSizeOf(T));
if (@typeInfo(T) != .Float) {
@compileError("isInf not implemented for " ++ @typeName(T));
}
const remove_sign = ~@as(TBits, 0) >> 1;
return @bitCast(TBits, x) & remove_sign == @bitCast(TBits, math.inf(T));
}
/// Returns whether x is an infinity with a positive sign.
pub fn isPositiveInf(x: anytype) bool {
const T = @TypeOf(x);
switch (T) {
f16 => {
return @bitCast(u16, x) == 0x7C00;
},
f32 => {
return @bitCast(u32, x) == 0x7F800000;
},
f64 => {
return @bitCast(u64, x) == 0x7FF << 52;
},
f128 => {
return @bitCast(u128, x) == 0x7FFF << 112;
},
else => {
@compileError("isPositiveInf not implemented for " ++ @typeName(T));
},
}
return x == math.inf(@TypeOf(x));
}
/// Returns whether x is an infinity with a negative sign.
pub fn isNegativeInf(x: anytype) bool {
const T = @TypeOf(x);
switch (T) {
f16 => {
return @bitCast(u16, x) == 0xFC00;
},
f32 => {
return @bitCast(u32, x) == 0xFF800000;
},
f64 => {
return @bitCast(u64, x) == 0xFFF << 52;
},
f128 => {
return @bitCast(u128, x) == 0xFFFF << 112;
},
else => {
@compileError("isNegativeInf not implemented for " ++ @typeName(T));
},
}
return x == -math.inf(@TypeOf(x));
}
test "math.isInf" {
try expect(!isInf(@as(f16, 0.0)));
try expect(!isInf(@as(f16, -0.0)));
try expect(!isInf(@as(f32, 0.0)));
try expect(!isInf(@as(f32, -0.0)));
try expect(!isInf(@as(f64, 0.0)));
try expect(!isInf(@as(f64, -0.0)));
try expect(!isInf(@as(f128, 0.0)));
try expect(!isInf(@as(f128, -0.0)));
try expect(isInf(math.inf(f16)));
try expect(isInf(-math.inf(f16)));
try expect(isInf(math.inf(f32)));
try expect(isInf(-math.inf(f32)));
try expect(isInf(math.inf(f64)));
try expect(isInf(-math.inf(f64)));
try expect(isInf(math.inf(f128)));
try expect(isInf(-math.inf(f128)));
// TODO remove when #11391 is resolved
if (@import("builtin").os.tag == .freebsd) return error.SkipZigTest;
inline for ([_]type{ f16, f32, f64, f80, f128 }) |T| {
try expect(!isInf(@as(T, 0.0)));
try expect(!isInf(@as(T, -0.0)));
try expect(isInf(math.inf(T)));
try expect(isInf(-math.inf(T)));
}
}
test "math.isPositiveInf" {
try expect(!isPositiveInf(@as(f16, 0.0)));
try expect(!isPositiveInf(@as(f16, -0.0)));
try expect(!isPositiveInf(@as(f32, 0.0)));
try expect(!isPositiveInf(@as(f32, -0.0)));
try expect(!isPositiveInf(@as(f64, 0.0)));
try expect(!isPositiveInf(@as(f64, -0.0)));
try expect(!isPositiveInf(@as(f128, 0.0)));
try expect(!isPositiveInf(@as(f128, -0.0)));
try expect(isPositiveInf(math.inf(f16)));
try expect(!isPositiveInf(-math.inf(f16)));
try expect(isPositiveInf(math.inf(f32)));
try expect(!isPositiveInf(-math.inf(f32)));
try expect(isPositiveInf(math.inf(f64)));
try expect(!isPositiveInf(-math.inf(f64)));
try expect(isPositiveInf(math.inf(f128)));
try expect(!isPositiveInf(-math.inf(f128)));
// TODO remove when #11391 is resolved
if (@import("builtin").os.tag == .freebsd) return error.SkipZigTest;
inline for ([_]type{ f16, f32, f64, f80, f128 }) |T| {
try expect(!isPositiveInf(@as(T, 0.0)));
try expect(!isPositiveInf(@as(T, -0.0)));
try expect(isPositiveInf(math.inf(T)));
try expect(!isPositiveInf(-math.inf(T)));
}
}
test "math.isNegativeInf" {
try expect(!isNegativeInf(@as(f16, 0.0)));
try expect(!isNegativeInf(@as(f16, -0.0)));
try expect(!isNegativeInf(@as(f32, 0.0)));
try expect(!isNegativeInf(@as(f32, -0.0)));
try expect(!isNegativeInf(@as(f64, 0.0)));
try expect(!isNegativeInf(@as(f64, -0.0)));
try expect(!isNegativeInf(@as(f128, 0.0)));
try expect(!isNegativeInf(@as(f128, -0.0)));
try expect(!isNegativeInf(math.inf(f16)));
try expect(isNegativeInf(-math.inf(f16)));
try expect(!isNegativeInf(math.inf(f32)));
try expect(isNegativeInf(-math.inf(f32)));
try expect(!isNegativeInf(math.inf(f64)));
try expect(isNegativeInf(-math.inf(f64)));
try expect(!isNegativeInf(math.inf(f128)));
try expect(isNegativeInf(-math.inf(f128)));
// TODO remove when #11391 is resolved
if (@import("builtin").os.tag == .freebsd) return error.SkipZigTest;
inline for ([_]type{ f16, f32, f64, f80, f128 }) |T| {
try expect(!isNegativeInf(@as(T, 0.0)));
try expect(!isNegativeInf(@as(T, -0.0)));
try expect(!isNegativeInf(math.inf(T)));
try expect(isNegativeInf(-math.inf(T)));
}
}