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| // Licensed to the Apache Software Foundation (ASF) under one | |
| // or more contributor license agreements. See the NOTICE file | |
| // distributed with this work for additional information | |
| // regarding copyright ownership. The ASF licenses this file | |
| // to you under the Apache License, Version 2.0 (the | |
| // "License"); you may not use this file except in compliance | |
| // with the License. You may obtain a copy of the License at | |
| // | |
| // http://www.apache.org/licenses/LICENSE-2.0 | |
| // | |
| // Unless required by applicable law or agreed to in writing, | |
| // software distributed under the License is distributed on an | |
| // "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY | |
| // KIND, either express or implied. See the License for the | |
| // specific language governing permissions and limitations | |
| // under the License. | |
| const f64 = new Float64Array(1); | |
| const u32 = new Uint32Array(f64.buffer); | |
| /** | |
| * Convert uint16 (logically a float16) to a JS float64. Inspired by numpy's `npy_half_to_double`: | |
| * https://github.com/numpy/numpy/blob/5a5987291dc95376bb098be8d8e5391e89e77a2c/numpy/core/src/npymath/halffloat.c#L29 | |
| * @param h {number} the uint16 to convert | |
| * @private | |
| * @ignore | |
| */ | |
| export function uint16ToFloat64(h) { | |
| const expo = (h & 0x7C00) >> 10; | |
| const sigf = (h & 0x03FF) / 1024; | |
| const sign = Math.pow((-1), ((h & 0x8000) >> 15)); | |
| switch (expo) { | |
| case 0x1F: return sign * (sigf ? Number.NaN : 1 / 0); | |
| case 0x00: return sign * (sigf ? 6.103515625e-5 * sigf : 0); | |
| } | |
| return sign * (Math.pow(2, (expo - 15))) * (1 + sigf); | |
| } | |
| /** | |
| * Convert a float64 to uint16 (assuming the float64 is logically a float16). Inspired by numpy's `npy_double_to_half`: | |
| * https://github.com/numpy/numpy/blob/5a5987291dc95376bb098be8d8e5391e89e77a2c/numpy/core/src/npymath/halffloat.c#L43 | |
| * @param d {number} The float64 to convert | |
| * @private | |
| * @ignore | |
| */ | |
| export function float64ToUint16(d) { | |
| if (d !== d) { | |
| return 0x7E00; | |
| } // NaN | |
| f64[0] = d; | |
| // Magic numbers: | |
| // 0x80000000 = 10000000 00000000 00000000 00000000 -- masks the 32nd bit | |
| // 0x7ff00000 = 01111111 11110000 00000000 00000000 -- masks the 21st-31st bits | |
| // 0x000fffff = 00000000 00001111 11111111 11111111 -- masks the 1st-20th bit | |
| const sign = (u32[1] & 0x80000000) >> 16 & 0xFFFF; | |
| let expo = (u32[1] & 0x7FF00000), sigf = 0x0000; | |
| if (expo >= 0x40F00000) { | |
| // | |
| // If exponent overflowed, the float16 is either NaN or Infinity. | |
| // Rules to propagate the sign bit: mantissa > 0 ? NaN : +/-Infinity | |
| // | |
| // Magic numbers: | |
| // 0x40F00000 = 01000000 11110000 00000000 00000000 -- 6-bit exponent overflow | |
| // 0x7C000000 = 01111100 00000000 00000000 00000000 -- masks the 27th-31st bits | |
| // | |
| // returns: | |
| // qNaN, aka 32256 decimal, 0x7E00 hex, or 01111110 00000000 binary | |
| // sNaN, aka 32000 decimal, 0x7D00 hex, or 01111101 00000000 binary | |
| // +inf, aka 31744 decimal, 0x7C00 hex, or 01111100 00000000 binary | |
| // -inf, aka 64512 decimal, 0xFC00 hex, or 11111100 00000000 binary | |
| // | |
| // If mantissa is greater than 23 bits, set to +Infinity like numpy | |
| if (u32[0] > 0) { | |
| expo = 0x7C00; | |
| } | |
| else { | |
| expo = (expo & 0x7C000000) >> 16; | |
| sigf = (u32[1] & 0x000FFFFF) >> 10; | |
| } | |
| } | |
| else if (expo <= 0x3F000000) { | |
| // | |
| // If exponent underflowed, the float is either signed zero or subnormal. | |
| // | |
| // Magic numbers: | |
| // 0x3F000000 = 00111111 00000000 00000000 00000000 -- 6-bit exponent underflow | |
| // | |
| sigf = 0x100000 + (u32[1] & 0x000FFFFF); | |
| sigf = 0x100000 + (sigf << ((expo >> 20) - 998)) >> 21; | |
| expo = 0; | |
| } | |
| else { | |
| // | |
| // No overflow or underflow, rebase the exponent and round the mantissa | |
| // Magic numbers: | |
| // 0x200 = 00000010 00000000 -- masks off the 10th bit | |
| // | |
| // Ensure the first mantissa bit (the 10th one) is 1 and round | |
| expo = (expo - 0x3F000000) >> 10; | |
| sigf = ((u32[1] & 0x000FFFFF) + 0x200) >> 10; | |
| } | |
| return sign | expo | sigf & 0xFFFF; | |
| } | |
| //# sourceMappingURL=math.mjs.map | |