23 lines
753 B
Rust
23 lines
753 B
Rust
use crate::board::Bitboard;
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/// A type representing the magic board indexing a given [Square].
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#[allow(unused)] // FIXME: remove once used
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pub struct Magic {
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/// Magic number.
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magic: u64,
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/// Base offset into the magic square table.
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offset: usize,
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/// Mask to apply to the blocker board before applying the magic.
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mask: Bitboard,
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/// Length of the resulting mask after applying the magic.
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shift: u8,
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}
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impl Magic {
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#[allow(unused)] // FIXME: remove once used
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pub fn get_index(&self, blockers: Bitboard) -> usize {
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let relevant_occupancy = (blockers & self.mask).0;
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let base_index = ((relevant_occupancy.wrapping_mul(self.magic)) >> self.shift) as usize;
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base_index + self.offset
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}
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}
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