33 lines
790 B
Rust
33 lines
790 B
Rust
use num::PrimInt;
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const b_m16_interleave: [u8; 8] = [0, 49, 49, 41, 90, 27, 117, 10];
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pub fn sin8(theta: u8) -> u8 {
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let mut offset: u8 = theta;
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if theta & 0x40 != 0 {
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offset = 255 - offset;
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}
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offset &= 0x3f;
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let mut secoffset: u8 = offset & 0x0f;
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if theta & 0x40 != 0 {
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secoffset += 1;
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}
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let section: u8 = offset.unsigned_shr(4);
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let s2: u8 = section * 2;
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let b: u8 = b_m16_interleave[s2 as usize];
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let m16: u8 = b_m16_interleave[s2 as usize + 1];
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let mx: u8 = m16.wrapping_mul(secoffset).unsigned_shr(4);
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let mut y: i8 = mx as i8 + b as i8;
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if theta & 0x80 != 0 {
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y = -y;
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}
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y = y.wrapping_add(128u8 as i8);
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return y as u8;
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}
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pub fn cos8(theta: u8) -> u8 {
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sin8(theta.wrapping_add(64))
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}
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