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Diffstat (limited to '')
-rw-r--r-- | vendor/ryu/src/d2s_small_table.rs | 142 |
1 files changed, 142 insertions, 0 deletions
diff --git a/vendor/ryu/src/d2s_small_table.rs b/vendor/ryu/src/d2s_small_table.rs new file mode 100644 index 000000000..262fc04f9 --- /dev/null +++ b/vendor/ryu/src/d2s_small_table.rs @@ -0,0 +1,142 @@ +// Translated from C to Rust. The original C code can be found at +// https://github.com/ulfjack/ryu and carries the following license: +// +// Copyright 2018 Ulf Adams +// +// The contents of this file may be used under the terms of the Apache License, +// Version 2.0. +// +// (See accompanying file LICENSE-Apache or copy at +// http://www.apache.org/licenses/LICENSE-2.0) +// +// Alternatively, the contents of this file may be used under the terms of +// the Boost Software License, Version 1.0. +// (See accompanying file LICENSE-Boost or copy at +// https://www.boost.org/LICENSE_1_0.txt) +// +// Unless required by applicable law or agreed to in writing, this software +// is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +// KIND, either express or implied. + +use crate::common::*; + +pub static DOUBLE_POW5_INV_SPLIT2: [(u64, u64); 15] = [ + (1, 2305843009213693952), + (5955668970331000884, 1784059615882449851), + (8982663654677661702, 1380349269358112757), + (7286864317269821294, 2135987035920910082), + (7005857020398200553, 1652639921975621497), + (17965325103354776697, 1278668206209430417), + (8928596168509315048, 1978643211784836272), + (10075671573058298858, 1530901034580419511), + (597001226353042382, 1184477304306571148), + (1527430471115325346, 1832889850782397517), + (12533209867169019542, 1418129833677084982), + (5577825024675947042, 2194449627517475473), + (11006974540203867551, 1697873161311732311), + (10313493231639821582, 1313665730009899186), + (12701016819766672773, 2032799256770390445), +]; + +pub static POW5_INV_OFFSETS: [u32; 19] = [ + 0x54544554, 0x04055545, 0x10041000, 0x00400414, 0x40010000, 0x41155555, 0x00000454, 0x00010044, + 0x40000000, 0x44000041, 0x50454450, 0x55550054, 0x51655554, 0x40004000, 0x01000001, 0x00010500, + 0x51515411, 0x05555554, 0x00000000, +]; + +pub static DOUBLE_POW5_SPLIT2: [(u64, u64); 13] = [ + (0, 1152921504606846976), + (0, 1490116119384765625), + (1032610780636961552, 1925929944387235853), + (7910200175544436838, 1244603055572228341), + (16941905809032713930, 1608611746708759036), + (13024893955298202172, 2079081953128979843), + (6607496772837067824, 1343575221513417750), + (17332926989895652603, 1736530273035216783), + (13037379183483547984, 2244412773384604712), + (1605989338741628675, 1450417759929778918), + (9630225068416591280, 1874621017369538693), + (665883850346957067, 1211445438634777304), + (14931890668723713708, 1565756531257009982), +]; + +pub static POW5_OFFSETS: [u32; 21] = [ + 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x40000000, 0x59695995, 0x55545555, 0x56555515, + 0x41150504, 0x40555410, 0x44555145, 0x44504540, 0x45555550, 0x40004000, 0x96440440, 0x55565565, + 0x54454045, 0x40154151, 0x55559155, 0x51405555, 0x00000105, +]; + +pub static DOUBLE_POW5_TABLE: [u64; 26] = [ + 1, + 5, + 25, + 125, + 625, + 3125, + 15625, + 78125, + 390625, + 1953125, + 9765625, + 48828125, + 244140625, + 1220703125, + 6103515625, + 30517578125, + 152587890625, + 762939453125, + 3814697265625, + 19073486328125, + 95367431640625, + 476837158203125, + 2384185791015625, + 11920928955078125, + 59604644775390625, + 298023223876953125, +]; + +// Computes 5^i in the form required by Ryū. +#[cfg_attr(feature = "no-panic", inline)] +pub unsafe fn compute_pow5(i: u32) -> (u64, u64) { + let base = i / DOUBLE_POW5_TABLE.len() as u32; + let base2 = base * DOUBLE_POW5_TABLE.len() as u32; + let offset = i - base2; + debug_assert!(base < DOUBLE_POW5_SPLIT2.len() as u32); + let mul = *DOUBLE_POW5_SPLIT2.get_unchecked(base as usize); + if offset == 0 { + return mul; + } + debug_assert!(offset < DOUBLE_POW5_TABLE.len() as u32); + let m = *DOUBLE_POW5_TABLE.get_unchecked(offset as usize); + let b0 = m as u128 * mul.0 as u128; + let b2 = m as u128 * mul.1 as u128; + let delta = pow5bits(i as i32) - pow5bits(base2 as i32); + debug_assert!(i / 16 < POW5_OFFSETS.len() as u32); + let shifted_sum = (b0 >> delta) + + (b2 << (64 - delta)) + + ((*POW5_OFFSETS.get_unchecked((i / 16) as usize) >> ((i % 16) << 1)) & 3) as u128; + (shifted_sum as u64, (shifted_sum >> 64) as u64) +} + +// Computes 5^-i in the form required by Ryū. +#[cfg_attr(feature = "no-panic", inline)] +pub unsafe fn compute_inv_pow5(i: u32) -> (u64, u64) { + let base = (i + DOUBLE_POW5_TABLE.len() as u32 - 1) / DOUBLE_POW5_TABLE.len() as u32; + let base2 = base * DOUBLE_POW5_TABLE.len() as u32; + let offset = base2 - i; + debug_assert!(base < DOUBLE_POW5_INV_SPLIT2.len() as u32); + let mul = *DOUBLE_POW5_INV_SPLIT2.get_unchecked(base as usize); // 1/5^base2 + if offset == 0 { + return mul; + } + debug_assert!(offset < DOUBLE_POW5_TABLE.len() as u32); + let m = *DOUBLE_POW5_TABLE.get_unchecked(offset as usize); // 5^offset + let b0 = m as u128 * (mul.0 - 1) as u128; + let b2 = m as u128 * mul.1 as u128; // 1/5^base2 * 5^offset = 1/5^(base2-offset) = 1/5^i + let delta = pow5bits(base2 as i32) - pow5bits(i as i32); + debug_assert!(base < POW5_INV_OFFSETS.len() as u32); + let shifted_sum = ((b0 >> delta) + (b2 << (64 - delta))) + + 1 + + ((*POW5_INV_OFFSETS.get_unchecked((i / 16) as usize) >> ((i % 16) << 1)) & 3) as u128; + (shifted_sum as u64, (shifted_sum >> 64) as u64) +} |