1#[cfg_attr(assert_no_panic, no_panic::no_panic)]2pub fn remquo(mut x: f64, mut y: f64) -> (f64, i32) {3    let ux: u64 = x.to_bits();4    let mut uy: u64 = y.to_bits();5    let mut ex = ((ux >> 52) & 0x7ff) as i32;6    let mut ey = ((uy >> 52) & 0x7ff) as i32;7    let sx = (ux >> 63) != 0;8    let sy = (uy >> 63) != 0;9    let mut q: u32;10    let mut i: u64;11    let mut uxi: u64 = ux;1213    if (uy << 1) == 0 || y.is_nan() || ex == 0x7ff {14        return ((x * y) / (x * y), 0);15    }16    if (ux << 1) == 0 {17        return (x, 0);18    }1920    /* normalize x and y */21    if ex == 0 {22        i = uxi << 12;23        while (i >> 63) == 0 {24            ex -= 1;25            i <<= 1;26        }27        uxi <<= -ex + 1;28    } else {29        uxi &= (!0) >> 12;30        uxi |= 1 << 52;31    }32    if ey == 0 {33        i = uy << 12;34        while (i >> 63) == 0 {35            ey -= 1;36            i <<= 1;37        }38        uy <<= -ey + 1;39    } else {40        uy &= (!0) >> 12;41        uy |= 1 << 52;42    }4344    q = 0;4546    if ex + 1 != ey {47        if ex < ey {48            return (x, 0);49        }50        /* x mod y */51        while ex > ey {52            i = uxi.wrapping_sub(uy);53            if (i >> 63) == 0 {54                uxi = i;55                q += 1;56            }57            uxi <<= 1;58            q <<= 1;59            ex -= 1;60        }61        i = uxi.wrapping_sub(uy);62        if (i >> 63) == 0 {63            uxi = i;64            q += 1;65        }66        if uxi == 0 {67            ex = -60;68        } else {69            while (uxi >> 52) == 0 {70                uxi <<= 1;71                ex -= 1;72            }73        }74    }7576    /* scale result and decide between |x| and |x|-|y| */77    if ex > 0 {78        uxi -= 1 << 52;79        uxi |= (ex as u64) << 52;80    } else {81        uxi >>= -ex + 1;82    }83    x = f64::from_bits(uxi);84    if sy {85        y = -y;86    }87    if ex == ey || (ex + 1 == ey && (2.0 * x > y || (2.0 * x == y && (q % 2) != 0))) {88        x -= y;89        // TODO: this matches musl behavior, but it is incorrect90        q = q.wrapping_add(1);91    }92    q &= 0x7fffffff;93    let quo = if sx ^ sy { -(q as i32) } else { q as i32 };94    if sx { (-x, quo) } else { (x, quo) }95}9697#[cfg(test)]98mod tests {99    use super::remquo;100101    #[test]102    fn test_q_overflow() {103        // 0xc000000000000001, 0x04c0000000000004104        let _ = remquo(-2.0000000000000004, 8.406091369059082e-286);105    }106}