#[cfg_attr(all(test, assert_no_panic), no_panic::no_panic)] pub fn remquo(mut x: f64, mut y: f64) -> (f64, i32) { let ux: u64 = x.to_bits(); let mut uy: u64 = y.to_bits(); let mut ex = ((ux >> 52) & 0x7ff) as i32; let mut ey = ((uy >> 52) & 0x7ff) as i32; let sx = (ux >> 63) != 0; let sy = (uy >> 63) != 0; let mut q: u32; let mut i: u64; let mut uxi: u64 = ux; if (uy << 1) == 0 || y.is_nan() || ex == 0x7ff { return ((x * y) / (x * y), 0); } if (ux << 1) == 0 { return (x, 0); } /* normalize x and y */ if ex == 0 { i = uxi << 12; while (i >> 63) == 0 { ex -= 1; i <<= 1; } uxi <<= -ex + 1; } else { uxi &= (!0) >> 12; uxi |= 1 << 52; } if ey == 0 { i = uy << 12; while (i >> 63) == 0 { ey -= 1; i <<= 1; } uy <<= -ey + 1; } else { uy &= (!0) >> 12; uy |= 1 << 52; } q = 0; if ex + 1 != ey { if ex < ey { return (x, 0); } /* x mod y */ while ex > ey { i = uxi.wrapping_sub(uy); if (i >> 63) == 0 { uxi = i; q += 1; } uxi <<= 1; q <<= 1; ex -= 1; } i = uxi.wrapping_sub(uy); if (i >> 63) == 0 { uxi = i; q += 1; } if uxi == 0 { ex = -60; } else { while (uxi >> 52) == 0 { uxi <<= 1; ex -= 1; } } } /* scale result and decide between |x| and |x|-|y| */ if ex > 0 { uxi -= 1 << 52; uxi |= (ex as u64) << 52; } else { uxi >>= -ex + 1; } x = f64::from_bits(uxi); if sy { y = -y; } if ex == ey || (ex + 1 == ey && (2.0 * x > y || (2.0 * x == y && (q % 2) != 0))) { x -= y; // TODO: this matches musl behavior, but it is incorrect q = q.wrapping_add(1); } q &= 0x7fffffff; let quo = if sx ^ sy { -(q as i32) } else { q as i32 }; if sx { (-x, quo) } else { (x, quo) } } #[cfg(test)] mod tests { use super::remquo; #[test] fn test_q_overflow() { // 0xc000000000000001, 0x04c0000000000004 let _ = remquo(-2.0000000000000004, 8.406091369059082e-286); } }