| 1 | // Adapted from https://github.com/Alexhuszagh/rust-lexical. |
| 2 | |
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| 3 | //! Bit-shift helpers. |
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| 4 | |
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| 5 | use super::float::ExtendedFloat; |
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| 6 | use core::mem; |
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| 7 | |
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| 8 | // Shift extended-precision float right `shift` bytes. |
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| 9 | #[inline ] |
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| 10 | pub(crate) fn shr(fp: &mut ExtendedFloat, shift: i32) { |
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| 11 | let bits: u64 = mem::size_of::<u64>() as u64 * 8; |
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| 12 | debug_assert!((shift as u64) < bits, "shr() overflow in shift right." ); |
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| 13 | |
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| 14 | fp.mant >>= shift; |
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| 15 | fp.exp += shift; |
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| 16 | } |
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| 17 | |
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| 18 | // Shift extended-precision float right `shift` bytes. |
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| 19 | // |
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| 20 | // Accepts when the shift is the same as the type size, and |
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| 21 | // sets the value to 0. |
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| 22 | #[inline ] |
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| 23 | pub(crate) fn overflowing_shr(fp: &mut ExtendedFloat, shift: i32) { |
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| 24 | let bits: u64 = mem::size_of::<u64>() as u64 * 8; |
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| 25 | debug_assert!( |
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| 26 | (shift as u64) <= bits, |
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| 27 | "overflowing_shr() overflow in shift right." |
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| 28 | ); |
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| 29 | |
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| 30 | fp.mant = if shift as u64 == bits { |
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| 31 | 0 |
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| 32 | } else { |
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| 33 | fp.mant >> shift |
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| 34 | }; |
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| 35 | fp.exp += shift; |
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| 36 | } |
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| 37 | |
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| 38 | // Shift extended-precision float left `shift` bytes. |
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| 39 | #[inline ] |
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| 40 | pub(crate) fn shl(fp: &mut ExtendedFloat, shift: i32) { |
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| 41 | let bits: u64 = mem::size_of::<u64>() as u64 * 8; |
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| 42 | debug_assert!((shift as u64) < bits, "shl() overflow in shift left." ); |
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| 43 | |
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| 44 | fp.mant <<= shift; |
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| 45 | fp.exp -= shift; |
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| 46 | } |
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| 47 | |
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