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fmt: fix f80 hex formatting #13296

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Merged
andrewrk merged 1 commit into from
Oct 25, 2022
Merged

fmt: fix f80 hex formatting #13296

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13 changes: 9 additions & 4 deletions lib/std/fmt.zig
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Original file line number Diff line number Diff line change
Expand Up @@ -1207,10 +1207,9 @@ pub fn formatFloatHexadecimal(
mantissa |= 1 << fractional_bits; // Add the implicit integer bit.
}

// Fill in zeroes to round the mantissa width to a multiple of 4.
if (T == f16) mantissa <<= 2 else if (T == f32) mantissa <<= 1;

const mantissa_digits = (fractional_bits + 3) / 4;
// Fill in zeroes to round the fraction width to a multiple of 4.
mantissa <<= mantissa_digits * 4 - fractional_bits;

if (options.precision) |precision| {
// Round if needed.
Expand Down Expand Up @@ -2317,33 +2316,39 @@ test "float.hexadecimal" {
try expectFmt("f16: 0x1.554p-2", "f16: {x}", .{@as(f16, 1.0 / 3.0)});
try expectFmt("f32: 0x1.555556p-2", "f32: {x}", .{@as(f32, 1.0 / 3.0)});
try expectFmt("f64: 0x1.5555555555555p-2", "f64: {x}", .{@as(f64, 1.0 / 3.0)});
try expectFmt("f80: 0x1.5555555555555556p-2", "f80: {x}", .{@as(f80, 1.0 / 3.0)});
try expectFmt("f128: 0x1.5555555555555555555555555555p-2", "f128: {x}", .{@as(f128, 1.0 / 3.0)});

try expectFmt("f16: 0x1p-14", "f16: {x}", .{math.floatMin(f16)});
try expectFmt("f32: 0x1p-126", "f32: {x}", .{math.floatMin(f32)});
try expectFmt("f64: 0x1p-1022", "f64: {x}", .{math.floatMin(f64)});
try expectFmt("f80: 0x1p-16382", "f80: {x}", .{math.floatMin(f80)});
try expectFmt("f128: 0x1p-16382", "f128: {x}", .{math.floatMin(f128)});

try expectFmt("f16: 0x0.004p-14", "f16: {x}", .{math.floatTrueMin(f16)});
try expectFmt("f32: 0x0.000002p-126", "f32: {x}", .{math.floatTrueMin(f32)});
try expectFmt("f64: 0x0.0000000000001p-1022", "f64: {x}", .{math.floatTrueMin(f64)});
try expectFmt("f80: 0x0.0000000000000002p-16382", "f80: {x}", .{math.floatTrueMin(f80)});
try expectFmt("f128: 0x0.0000000000000000000000000001p-16382", "f128: {x}", .{math.floatTrueMin(f128)});

try expectFmt("f16: 0x1.ffcp15", "f16: {x}", .{math.floatMax(f16)});
try expectFmt("f32: 0x1.fffffep127", "f32: {x}", .{math.floatMax(f32)});
try expectFmt("f64: 0x1.fffffffffffffp1023", "f64: {x}", .{math.floatMax(f64)});
try expectFmt("f80: 0x1.fffffffffffffffep16383", "f80: {x}", .{math.floatMax(f80)});
try expectFmt("f128: 0x1.ffffffffffffffffffffffffffffp16383", "f128: {x}", .{math.floatMax(f128)});
}

test "float.hexadecimal.precision" {
try expectFmt("f16: 0x1.5p-2", "f16: {x:.1}", .{@as(f16, 1.0 / 3.0)});
try expectFmt("f32: 0x1.555p-2", "f32: {x:.3}", .{@as(f32, 1.0 / 3.0)});
try expectFmt("f64: 0x1.55555p-2", "f64: {x:.5}", .{@as(f64, 1.0 / 3.0)});
try expectFmt("f128: 0x1.5555555p-2", "f128: {x:.7}", .{@as(f128, 1.0 / 3.0)});
try expectFmt("f80: 0x1.5555555p-2", "f80: {x:.7}", .{@as(f80, 1.0 / 3.0)});
try expectFmt("f128: 0x1.555555555p-2", "f128: {x:.9}", .{@as(f128, 1.0 / 3.0)});

try expectFmt("f16: 0x1.00000p0", "f16: {x:.5}", .{@as(f16, 1.0)});
try expectFmt("f32: 0x1.00000p0", "f32: {x:.5}", .{@as(f32, 1.0)});
try expectFmt("f64: 0x1.00000p0", "f64: {x:.5}", .{@as(f64, 1.0)});
try expectFmt("f80: 0x1.00000p0", "f80: {x:.5}", .{@as(f80, 1.0)});
try expectFmt("f128: 0x1.00000p0", "f128: {x:.5}", .{@as(f128, 1.0)});
}

Expand Down