authorgravatar for hmccarty@pm.meHarrison McCarty <hmccarty@pm.me> 2024-06-30 04:12:52-07:00
committergravatar for marc@tiehu.isMarc Tiehuis <marc@tiehu.is> 2024-07-14 11:19:34+12:00
log8ff01f78f314a743df8c8f085a02416bb1ce0c72
tree052e28d9141c7d4a04c7680beedd34d6b04f91f5
parent959d227d1370c9cf9198ed111e3a8bca15a7e47b

std.fmt.parseFloat: add f80 formatFloat support

7 files changed, 79 insertions(+), 33 deletions(-)

lib/std/fmt/format_float.zig+6-8
......@@ -1521,15 +1521,13 @@ fn check(comptime T: type, value: T, comptime expected: []const u8) !void {
15211521 const s = try formatFloat(&buf, value, .{});
15221522 try std.testing.expectEqualStrings(expected, s);
15231523
1524 if (@bitSizeOf(T) != 80) {
1525 const o = try std.fmt.parseFloat(T, s);
1526 const o_bits: I = @bitCast(o);
1524 const o = try std.fmt.parseFloat(T, s);
1525 const o_bits: I = @bitCast(o);
15271526
1528 if (std.math.isNan(value)) {
1529 try std.testing.expect(std.math.isNan(o));
1530 } else {
1531 try std.testing.expectEqual(value_bits, o_bits);
1532 }
1527 if (std.math.isNan(value)) {
1528 try std.testing.expect(std.math.isNan(o));
1529 } else {
1530 try std.testing.expectEqual(value_bits, o_bits);
15331531 }
15341532}
15351533
lib/std/fmt/parse_float.zig+24-9
......@@ -21,10 +21,6 @@ pub fn parseFloat(comptime T: type, s: []const u8) ParseFloatError!T {
2121 @compileError("Cannot parse a float into a non-floating point type.");
2222 }
2323
24 if (T == f80) {
25 @compileError("TODO support parsing float to f80");
26 }
27
2824 if (s.len == 0) {
2925 return error.InvalidCharacter;
3026 }
......@@ -75,7 +71,7 @@ pub fn parseFloat(comptime T: type, s: []const u8) ParseFloatError!T {
7571// See https://github.com/tiehuis/parse-number-fxx-test-data for a wider-selection of test-data.
7672
7773test parseFloat {
78 inline for ([_]type{ f16, f32, f64, f128 }) |T| {
74 inline for ([_]type{ f16, f32, f64, f80, f128 }) |T| {
7975 try testing.expectError(error.InvalidCharacter, parseFloat(T, ""));
8076 try testing.expectError(error.InvalidCharacter, parseFloat(T, " 1"));
8177 try testing.expectError(error.InvalidCharacter, parseFloat(T, "1abc"));
......@@ -131,7 +127,7 @@ test parseFloat {
131127}
132128
133129test "nan and inf" {
134 inline for ([_]type{ f16, f32, f64, f128 }) |T| {
130 inline for ([_]type{ f16, f32, f64, f80, f128 }) |T| {
135131 const Z = std.meta.Int(.unsigned, @typeInfo(T).Float.bits);
136132
137133 try expectEqual(@as(Z, @bitCast(try parseFloat(T, "nAn"))), @as(Z, @bitCast(std.math.nan(T))));
......@@ -144,6 +140,7 @@ test "largest normals" {
144140 try expectEqual(@as(u16, @bitCast(try parseFloat(f16, "65504"))), 0x7bff);
145141 try expectEqual(@as(u32, @bitCast(try parseFloat(f32, "3.4028234664E38"))), 0x7f7f_ffff);
146142 try expectEqual(@as(u64, @bitCast(try parseFloat(f64, "1.7976931348623157E308"))), 0x7fef_ffff_ffff_ffff);
143 try expectEqual(@as(u80, @bitCast(try parseFloat(f80, "1.189731495357231765E4932"))), 0x7ffe_ffff_ffff_ffff_ffff);
147144 try expectEqual(@as(u128, @bitCast(try parseFloat(f128, "1.1897314953572317650857593266280070162E4932"))), 0x7ffe_ffff_ffff_ffff_ffff_ffff_ffff_ffff);
148145}
149146
......@@ -152,8 +149,8 @@ test "#11169" {
152149}
153150
154151test "many_digits hex" {
155 const a: f32 = try std.fmt.parseFloat(f32, "0xffffffffffffffff.0p0");
156 const b: f32 = @floatCast(try std.fmt.parseFloat(f128, "0xffffffffffffffff.0p0"));
152 const a: f32 = try parseFloat(f32, "0xffffffffffffffff.0p0");
153 const b: f32 = @floatCast(try parseFloat(f128, "0xffffffffffffffff.0p0"));
157154 try std.testing.expectEqual(a, b);
158155}
159156
......@@ -163,6 +160,7 @@ test "hex.special" {
163160 try testing.expect(math.isPositiveInf(try parseFloat(f32, "+Inf")));
164161 try testing.expect(math.isNegativeInf(try parseFloat(f32, "-iNf")));
165162}
163
166164test "hex.zero" {
167165 try testing.expectEqual(@as(f32, 0.0), try parseFloat(f32, "0x0"));
168166 try testing.expectEqual(@as(f32, 0.0), try parseFloat(f32, "-0x0"));
......@@ -221,6 +219,23 @@ test "hex.f64" {
221219 try testing.expectEqual(try parseFloat(f64, "0x1p-1074"), math.floatTrueMin(f64));
222220 try testing.expectEqual(try parseFloat(f64, "-0x1p-1074"), -math.floatTrueMin(f64));
223221}
222
223test "hex.f80" {
224 try testing.expectEqual(try parseFloat(f80, "0x1p0"), 1.0);
225 try testing.expectEqual(try parseFloat(f80, "-0x1p-1"), -0.5);
226 try testing.expectEqual(try parseFloat(f80, "0x10p+10"), 16384.0);
227 try testing.expectEqual(try parseFloat(f80, "0x10p-10"), 0.015625);
228 // Max normalized value.
229 try testing.expectEqual(try parseFloat(f80, "0xf.fffffffffffffff7p+16380"), math.floatMax(f80));
230 try testing.expectEqual(try parseFloat(f80, "-0xf.fffffffffffffff7p+16380"), -math.floatMax(f80));
231 // Min normalized value.
232 try testing.expectEqual(try parseFloat(f80, "0x1p-16382"), math.floatMin(f80));
233 try testing.expectEqual(try parseFloat(f80, "-0x1p-16382"), -math.floatMin(f80));
234 // Min denormalized value.
235 try testing.expectEqual(try parseFloat(f80, "0x1p-16445"), math.floatTrueMin(f80));
236 try testing.expectEqual(try parseFloat(f80, "-0x1p-16445"), -math.floatTrueMin(f80));
237}
238
224239test "hex.f128" {
225240 try testing.expectEqual(try parseFloat(f128, "0x1p0"), 1.0);
226241 try testing.expectEqual(try parseFloat(f128, "-0x1p-1"), -0.5);
......@@ -232,7 +247,7 @@ test "hex.f128" {
232247 // Min normalized value.
233248 try testing.expectEqual(try parseFloat(f128, "0x1p-16382"), math.floatMin(f128));
234249 try testing.expectEqual(try parseFloat(f128, "-0x1p-16382"), -math.floatMin(f128));
235 // // Min denormalized value.
250 // Min denormalized value.
236251 try testing.expectEqual(try parseFloat(f128, "0x1p-16494"), math.floatTrueMin(f128));
237252 try testing.expectEqual(try parseFloat(f128, "-0x1p-16494"), -math.floatTrueMin(f128));
238253 // ensure round-to-even
lib/std/fmt/parse_float/FloatInfo.zig+23-3
......@@ -60,7 +60,7 @@ pub fn from(comptime T: type) Self {
6060 .max_exponent_fast_path_disguised = 7,
6161 .max_mantissa_fast_path = 2 << std.math.floatMantissaBits(T),
6262 // Slow + Eisel-Lemire
63 .mantissa_explicit_bits = std.math.floatMantissaBits(T),
63 .mantissa_explicit_bits = std.math.floatFractionalBits(T),
6464 .infinite_power = 0x1f,
6565 // Eisel-Lemire
6666 .smallest_power_of_ten = -26, // TODO: refine, fails one test
......@@ -81,7 +81,7 @@ pub fn from(comptime T: type) Self {
8181 .max_exponent_fast_path_disguised = 17,
8282 .max_mantissa_fast_path = 2 << std.math.floatMantissaBits(T),
8383 // Slow + Eisel-Lemire
84 .mantissa_explicit_bits = std.math.floatMantissaBits(T),
84 .mantissa_explicit_bits = std.math.floatFractionalBits(T),
8585 .infinite_power = 0xff,
8686 // Eisel-Lemire
8787 .smallest_power_of_ten = -65,
......@@ -106,6 +106,26 @@ pub fn from(comptime T: type) Self {
106106 .min_exponent_round_to_even = -4,
107107 .max_exponent_round_to_even = 23,
108108 },
109 f80 => .{
110 // Fast-Path
111 .min_exponent_fast_path = -27,
112 .max_exponent_fast_path = 27,
113 .max_exponent_fast_path_disguised = 46,
114 .max_mantissa_fast_path = 2 << std.math.floatMantissaBits(T),
115 // Slow + Eisel-Lemire
116 .mantissa_explicit_bits = std.math.floatFractionalBits(T),
117 .infinite_power = 0x7fff,
118 // Eisel-Lemire.
119 // NOTE: Not yet tested (no f80 eisel-lemire implementation)
120 .smallest_power_of_ten = -4966,
121 .largest_power_of_ten = 4932,
122 .minimum_exponent = -16382,
123 // 2^65 * 5^-q < 2^80
124 // 5^-q < 2^15
125 // => q >= -6
126 .min_exponent_round_to_even = -6,
127 .max_exponent_round_to_even = 28,
128 },
109129 f128 => .{
110130 // Fast-Path
111131 .min_exponent_fast_path = -48,
......@@ -113,7 +133,7 @@ pub fn from(comptime T: type) Self {
113133 .max_exponent_fast_path_disguised = 82,
114134 .max_mantissa_fast_path = 2 << std.math.floatMantissaBits(T),
115135 // Slow + Eisel-Lemire
116 .mantissa_explicit_bits = std.math.floatMantissaBits(T),
136 .mantissa_explicit_bits = std.math.floatFractionalBits(T),
117137 .infinite_power = 0x7fff,
118138 // Eisel-Lemire.
119139 // NOTE: Not yet tested (no f128 eisel-lemire implementation)
lib/std/fmt/parse_float/common.zig+7-2
......@@ -23,7 +23,11 @@ pub fn BiasedFp(comptime T: type) type {
2323 }
2424
2525 pub fn inf(comptime FloatT: type) Self {
26 return .{ .f = 0, .e = (1 << std.math.floatExponentBits(FloatT)) - 1 };
26 const e = (1 << std.math.floatExponentBits(FloatT)) - 1;
27 return switch (FloatT) {
28 f80 => .{ .f = 0x8000000000000000, .e = e },
29 else => .{ .f = 0, .e = e },
30 };
2731 }
2832
2933 pub fn eql(self: Self, other: Self) bool {
......@@ -45,6 +49,7 @@ pub fn floatFromUnsigned(comptime T: type, comptime MantissaT: type, v: Mantissa
4549 f16 => @as(f16, @bitCast(@as(u16, @truncate(v)))),
4650 f32 => @as(f32, @bitCast(@as(u32, @truncate(v)))),
4751 f64 => @as(f64, @bitCast(@as(u64, @truncate(v)))),
52 f80 => @as(f80, @bitCast(@as(u80, @truncate(v)))),
4853 f128 => @as(f128, @bitCast(v)),
4954 else => unreachable,
5055 };
......@@ -85,7 +90,7 @@ pub fn isDigit(c: u8, comptime base: u8) bool {
8590pub fn mantissaType(comptime T: type) type {
8691 return switch (T) {
8792 f16, f32, f64 => u64,
88 f128 => u128,
93 f80, f128 => u128,
8994 else => unreachable,
9095 };
9196}
lib/std/fmt/parse_float/convert_fast.zig+7
......@@ -46,6 +46,13 @@ fn fastPow10(comptime T: type, i: usize) T {
4646 0, 0, 0, 0, 0, 0, 0, 0,
4747 })[i & 31],
4848
49 f80 => ([32]f80{
50 1e0, 1e1, 1e2, 1e3, 1e4, 1e5, 1e6, 1e7,
51 1e8, 1e9, 1e10, 1e11, 1e12, 1e13, 1e14, 1e15,
52 1e16, 1e17, 1e18, 1e19, 1e20, 1e21, 1e22, 1e23,
53 1e24, 1e25, 1e26, 1e27, 0, 0, 0, 0,
54 })[i & 31],
55
4956 f128 => ([64]f128{
5057 1e0, 1e1, 1e2, 1e3, 1e4, 1e5, 1e6, 1e7,
5158 1e8, 1e9, 1e10, 1e11, 1e12, 1e13, 1e14, 1e15,
lib/std/fmt/parse_float/convert_hex.zig+6-5
......@@ -25,11 +25,12 @@ pub fn convertHex(comptime T: type, n_: Number(T)) T {
2525 const max_exp = math.floatExponentMax(T);
2626 const min_exp = math.floatExponentMin(T);
2727 const mantissa_bits = math.floatMantissaBits(T);
28 const fractional_bits = math.floatFractionalBits(T);
2829 const exp_bits = math.floatExponentBits(T);
2930 const exp_bias = min_exp - 1;
3031
31 // mantissa now implicitly divided by 2^mantissa_bits
32 n.exponent += mantissa_bits;
32 // mantissa now implicitly divided by 2^fractional_bits
33 n.exponent += fractional_bits;
3334
3435 // Shift mantissa and exponent to bring representation into float range.
3536 // Eventually we want a mantissa with a leading 1-bit followed by mantbits other bits.
......@@ -44,7 +45,7 @@ pub fn convertHex(comptime T: type, n_: Number(T)) T {
4445 if (n.many_digits) {
4546 n.mantissa |= 1;
4647 }
47 while (n.mantissa >> (1 + mantissa_bits + 2) != 0) {
48 while (n.mantissa >> (1 + fractional_bits + 2) != 0) {
4849 n.mantissa = (n.mantissa >> 1) | (n.mantissa & 1);
4950 n.exponent += 1;
5051 }
......@@ -64,14 +65,14 @@ pub fn convertHex(comptime T: type, n_: Number(T)) T {
6465 n.exponent += 2;
6566 if (round == 3) {
6667 n.mantissa += 1;
67 if (n.mantissa == 1 << (1 + mantissa_bits)) {
68 if (n.mantissa == 1 << (1 + fractional_bits)) {
6869 n.mantissa >>= 1;
6970 n.exponent += 1;
7071 }
7172 }
7273
7374 // Denormal or zero
74 if (n.mantissa >> mantissa_bits == 0) {
75 if (n.mantissa >> fractional_bits == 0) {
7576 n.exponent = exp_bias;
7677 }
7778
lib/std/fmt/parse_float/convert_slow.zig+6-6
......@@ -41,7 +41,7 @@ pub fn convertSlow(comptime T: type, s: []const u8) BiasedFp(T) {
4141 const MantissaT = mantissaType(T);
4242 const min_exponent = -(1 << (math.floatExponentBits(T) - 1)) + 1;
4343 const infinite_power = (1 << math.floatExponentBits(T)) - 1;
44 const mantissa_explicit_bits = math.floatMantissaBits(T);
44 const fractional_bits = math.floatFractionalBits(T);
4545
4646 var d = Decimal(T).parse(s); // no need to recheck underscores
4747 if (d.num_digits == 0 or d.decimal_point < Decimal(T).min_exponent) {
......@@ -97,9 +97,9 @@ pub fn convertSlow(comptime T: type, s: []const u8) BiasedFp(T) {
9797
9898 // Shift the decimal to the hidden bit, and then round the value
9999 // to get the high mantissa+1 bits.
100 d.leftShift(mantissa_explicit_bits + 1);
100 d.leftShift(fractional_bits + 1);
101101 var mantissa = d.round();
102 if (mantissa >= (@as(MantissaT, 1) << (mantissa_explicit_bits + 1))) {
102 if (mantissa >= (@as(MantissaT, 1) << (fractional_bits + 1))) {
103103 // Rounding up overflowed to the carry bit, need to
104104 // shift back to the hidden bit.
105105 d.rightShift(1);
......@@ -110,10 +110,10 @@ pub fn convertSlow(comptime T: type, s: []const u8) BiasedFp(T) {
110110 }
111111 }
112112 var power2 = exp2 - min_exponent;
113 if (mantissa < (@as(MantissaT, 1) << mantissa_explicit_bits)) {
113 if (mantissa < (@as(MantissaT, 1) << fractional_bits)) {
114114 power2 -= 1;
115115 }
116 // Zero out all the bits above the explicit mantissa bits.
117 mantissa &= (@as(MantissaT, 1) << mantissa_explicit_bits) - 1;
116 // Zero out all the bits above the mantissa bits.
117 mantissa &= (@as(MantissaT, 1) << math.floatMantissaBits(T)) - 1;
118118 return .{ .f = mantissa, .e = power2 };
119119}