diff options
Diffstat (limited to 'src/d2s_small_table.rs')
| -rw-r--r-- | src/d2s_small_table.rs | 71 |
1 files changed, 4 insertions, 67 deletions
diff --git a/src/d2s_small_table.rs b/src/d2s_small_table.rs index 08519a2..262fc04 100644 --- a/src/d2s_small_table.rs +++ b/src/d2s_small_table.rs @@ -19,10 +19,8 @@ // KIND, either express or implied. use crate::common::*; -#[cfg(not(integer128))] -use crate::d2s_intrinsics::*; -pub static DOUBLE_POW5_INV_SPLIT2: [(u64, u64); 13] = [ +pub static DOUBLE_POW5_INV_SPLIT2: [(u64, u64); 15] = [ (1, 2305843009213693952), (5955668970331000884, 1784059615882449851), (8982663654677661702, 1380349269358112757), @@ -36,6 +34,8 @@ pub static DOUBLE_POW5_INV_SPLIT2: [(u64, u64); 13] = [ (12533209867169019542, 1418129833677084982), (5577825024675947042, 2194449627517475473), (11006974540203867551, 1697873161311732311), + (10313493231639821582, 1313665730009899186), + (12701016819766672773, 2032799256770390445), ]; pub static POW5_INV_OFFSETS: [u32; 19] = [ @@ -96,7 +96,6 @@ pub static DOUBLE_POW5_TABLE: [u64; 26] = [ ]; // Computes 5^i in the form required by Ryū. -#[cfg(integer128)] #[cfg_attr(feature = "no-panic", inline)] pub unsafe fn compute_pow5(i: u32) -> (u64, u64) { let base = i / DOUBLE_POW5_TABLE.len() as u32; @@ -112,7 +111,7 @@ pub unsafe fn compute_pow5(i: u32) -> (u64, u64) { 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!(base < POW5_OFFSETS.len() as u32); + 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; @@ -120,7 +119,6 @@ pub unsafe fn compute_pow5(i: u32) -> (u64, u64) { } // Computes 5^-i in the form required by Ryū. -#[cfg(integer128)] #[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; @@ -142,64 +140,3 @@ pub unsafe fn compute_inv_pow5(i: u32) -> (u64, u64) { + ((*POW5_INV_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, and stores it in the given pointer. -#[cfg(not(integer128))] -#[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 (low1, mut high1) = umul128(m, mul.1); - let (low0, high0) = umul128(m, mul.0); - let sum = high0 + low1; - if sum < high0 { - high1 += 1; // overflow into high1 - } - // high1 | sum | low0 - let delta = pow5bits(i as i32) - pow5bits(base2 as i32); - debug_assert!(base < POW5_OFFSETS.len() as u32); - ( - shiftright128(low0, sum, delta as u32) - + ((*POW5_OFFSETS.get_unchecked((i / 16) as usize) >> ((i % 16) << 1)) & 3) as u64, - shiftright128(sum, high1, delta as u32), - ) -} - -// Computes 5^-i in the form required by Ryū, and stores it in the given pointer. -#[cfg(not(integer128))] -#[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); - let (low1, mut high1) = umul128(m, mul.1); - let (low0, high0) = umul128(m, mul.0 - 1); - let sum = high0 + low1; - if sum < high0 { - high1 += 1; // overflow into high1 - } - // high1 | sum | low0 - let delta = pow5bits(base2 as i32) - pow5bits(i as i32); - debug_assert!(base < POW5_INV_OFFSETS.len() as u32); - ( - shiftright128(low0, sum, delta as u32) - + 1 - + ((*POW5_INV_OFFSETS.get_unchecked((i / 16) as usize) >> ((i % 16) << 1)) & 3) as u64, - shiftright128(sum, high1, delta as u32), - ) -} |