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| constexpr BoothSliceParams | compute_booth_slice_params_unchecked (size_t bit_offset, size_t window_bits, size_t num_uint64_limbs) noexcept |
| | Compute the Booth slice params for a window starting at absolute bit position bit_offset. The slice is [bit_offset - 1, bit_offset + window_bits); the bit at bit_offset - 1 is the shared boundary bit. The bottom window (bit_offset == 0) is encoded specially so the same recoding algebra applies — read "limb -1" as a zero-masked load.
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| BoothSliceParams | compute_booth_slice_params (size_t bit_offset, size_t window_bits, size_t num_uint64_limbs) noexcept |
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| template<size_t NUM_WINDOWS, size_t WINDOW_BITS, size_t NUM_UINT64_LIMBS> |
| constexpr std::array< BoothSliceParams, NUM_WINDOWS > | make_booth_slice_params () noexcept |
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| template<size_t NUM_WINDOWS, size_t WINDOW_BITS, size_t LOW_WINDOW_BITS, size_t NUM_UINT64_LIMBS> |
| constexpr std::array< BoothSliceParams, NUM_WINDOWS > | make_offset_booth_slice_params () noexcept |
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| uint32_t | booth_packed_digit (const uint64_t *s, const BoothSliceParams &sp, size_t window_bits) noexcept |
| | Read a (window_bits+1)-bit window from s[] (uint64 limbs) and apply Constantine's signedWindowEncoding to produce a (sign | magnitude) packed digit: bit 31 = sign (1 = negative), bits 0..30 = magnitude in [0, 2^(window_bits-1)]. Magnitude 0 means the window contributes nothing.
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| uint32_t bb::ecc::booth::booth_packed_digit |
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const uint64_t * |
s, |
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const BoothSliceParams & |
sp, |
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size_t |
window_bits |
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inlinenoexcept |
Read a (window_bits+1)-bit window from s[] (uint64 limbs) and apply Constantine's signedWindowEncoding to produce a (sign | magnitude) packed digit: bit 31 = sign (1 = negative), bits 0..30 = magnitude in [0, 2^(window_bits-1)]. Magnitude 0 means the window contributes nothing.
Two unconditional limb loads; windows entirely inside one uint64 still work because hi_mask == 0, so hi_part vanishes without a branch.
Definition at line 146 of file booth_recode.hpp.
| constexpr BoothSliceParams bb::ecc::booth::compute_booth_slice_params_unchecked |
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size_t |
bit_offset, |
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size_t |
window_bits, |
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size_t |
num_uint64_limbs |
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constexprnoexcept |
Compute the Booth slice params for a window starting at absolute bit position bit_offset. The slice is [bit_offset - 1, bit_offset + window_bits); the bit at bit_offset - 1 is the shared boundary bit. The bottom window (bit_offset == 0) is encoded specially so the same recoding algebra applies — read "limb -1" as a zero-masked load.
constexpr so callers with compile-time window schedules (element_impl's GLV-endo 32-window table) can materialise the param array at compile time, while runtime-schedule callers (Pippenger) use the checked wrapper at runtime.
Definition at line 49 of file booth_recode.hpp.
1.9.8