315 lines
8.9 KiB
Rust
315 lines
8.9 KiB
Rust
use core::intrinsics;
|
|
use int::{Int, LargeInt};
|
|
|
|
/// Returns `n / d`
|
|
#[cfg(not(all(feature = "c", target_arch = "arm", not(target_os = "ios"), not(thumbv6m))))]
|
|
#[cfg_attr(all(not(test), not(target_arch = "arm")), no_mangle)]
|
|
#[cfg_attr(all(not(test), target_arch = "arm"), inline(always))]
|
|
pub extern "C" fn __udivsi3(n: u32, d: u32) -> u32 {
|
|
// Special cases
|
|
if d == 0 {
|
|
// NOTE This should be unreachable in safe Rust because the program will panic before
|
|
// this intrinsic is called
|
|
unsafe {
|
|
intrinsics::abort()
|
|
}
|
|
}
|
|
|
|
if n == 0 {
|
|
return 0;
|
|
}
|
|
|
|
let mut sr = d.leading_zeros().wrapping_sub(n.leading_zeros());
|
|
|
|
// d > n
|
|
if sr > u32::bits() - 1 {
|
|
return 0;
|
|
}
|
|
|
|
// d == 1
|
|
if sr == u32::bits() - 1 {
|
|
return n;
|
|
}
|
|
|
|
sr += 1;
|
|
|
|
// 1 <= sr <= u32::bits() - 1
|
|
let mut q = n << (u32::bits() - sr);
|
|
let mut r = n >> sr;
|
|
|
|
let mut carry = 0;
|
|
for _ in 0..sr {
|
|
// r:q = ((r:q) << 1) | carry
|
|
r = (r << 1) | (q >> (u32::bits() - 1));
|
|
q = (q << 1) | carry;
|
|
|
|
// carry = 0;
|
|
// if r > d {
|
|
// r -= d;
|
|
// carry = 1;
|
|
// }
|
|
|
|
let s = (d.wrapping_sub(r).wrapping_sub(1)) as i32 >> (u32::bits() - 1);
|
|
carry = (s & 1) as u32;
|
|
r -= d & s as u32;
|
|
}
|
|
|
|
(q << 1) | carry
|
|
}
|
|
|
|
/// Returns `n % d`
|
|
#[cfg(not(all(feature = "c", target_arch = "arm", not(target_os = "ios"))))]
|
|
#[cfg_attr(not(test), no_mangle)]
|
|
pub extern "C" fn __umodsi3(n: u32, d: u32) -> u32 {
|
|
#[cfg(all(feature = "c", target_arch = "arm", not(target_os = "ios")))]
|
|
extern "C" {
|
|
fn __udivsi3(n: u32, d: u32) -> u32;
|
|
}
|
|
|
|
let q = match () {
|
|
#[cfg(all(feature = "c", target_arch = "arm", not(target_os = "ios")))]
|
|
() => unsafe { __udivsi3(n, d) },
|
|
#[cfg(not(all(feature = "c", target_arch = "arm", not(target_os = "ios"))))]
|
|
() => __udivsi3(n, d),
|
|
};
|
|
|
|
n - q * d
|
|
}
|
|
|
|
/// Returns `n / d` and sets `*rem = n % d`
|
|
#[cfg(not(all(feature = "c", target_arch = "arm", not(target_os = "ios"), not(thumbv6m))))]
|
|
#[cfg_attr(not(test), no_mangle)]
|
|
pub extern "C" fn __udivmodsi4(n: u32, d: u32, rem: Option<&mut u32>) -> u32 {
|
|
#[cfg(all(feature = "c", target_arch = "arm", not(target_os = "ios"), not(thumbv6m)))]
|
|
extern "C" {
|
|
fn __udivsi3(n: u32, d: u32) -> u32;
|
|
}
|
|
|
|
let q = match () {
|
|
#[cfg(all(feature = "c", target_arch = "arm", not(target_os = "ios"), not(thumbv6m)))]
|
|
() => unsafe { __udivsi3(n, d) },
|
|
#[cfg(not(all(feature = "c", target_arch = "arm", not(target_os = "ios"), not(thumbv6m))))]
|
|
() => __udivsi3(n, d),
|
|
};
|
|
if let Some(rem) = rem {
|
|
*rem = n - (q * d);
|
|
}
|
|
q
|
|
}
|
|
|
|
macro_rules! div_mod_intrinsics {
|
|
($udiv_intr:ident, $umod_intr:ident : $ty:ty) => {
|
|
div_mod_intrinsics!($udiv_intr, $umod_intr : $ty,
|
|
__udivmoddi4);
|
|
};
|
|
($udiv_intr:ident, $umod_intr:ident : $ty:ty, $divmod_intr:expr) => {
|
|
div_mod_intrinsics!($udiv_intr, $umod_intr : $ty,
|
|
$divmod_intr, $ty, |i|{ i });
|
|
};
|
|
($udiv_intr:ident, $umod_intr:ident : $ty:ty, $divmod_intr:expr,
|
|
$tyret:ty, $conv:expr) => {
|
|
/// Returns `n / d`
|
|
#[cfg_attr(not(test), no_mangle)]
|
|
pub extern "C" fn $udiv_intr(n: $ty, d: $ty) -> $tyret {
|
|
let r = $divmod_intr(n, d, None);
|
|
($conv)(r)
|
|
}
|
|
|
|
/// Returns `n % d`
|
|
#[cfg_attr(not(test), no_mangle)]
|
|
pub extern "C" fn $umod_intr(a: $ty, b: $ty) -> $tyret {
|
|
use core::mem;
|
|
|
|
let mut rem = unsafe { mem::uninitialized() };
|
|
$divmod_intr(a, b, Some(&mut rem));
|
|
($conv)(rem)
|
|
}
|
|
}
|
|
}
|
|
|
|
#[cfg(not(all(feature = "c", target_arch = "x86")))]
|
|
div_mod_intrinsics!(__udivdi3, __umoddi3: u64);
|
|
|
|
#[cfg(not(all(windows, target_pointer_width="64")))]
|
|
div_mod_intrinsics!(__udivti3, __umodti3: u128, u128_div_mod);
|
|
|
|
#[cfg(all(windows, target_pointer_width="64"))]
|
|
div_mod_intrinsics!(__udivti3, __umodti3: u128, u128_div_mod, ::U64x2, ::conv);
|
|
|
|
macro_rules! udivmod_inner {
|
|
($n:expr, $d:expr, $rem:expr, $ty:ty) => {{
|
|
let (n, d, rem) = ($n, $d, $rem);
|
|
// NOTE X is unknown, K != 0
|
|
if n.high() == 0 {
|
|
if d.high() == 0 {
|
|
// 0 X
|
|
// ---
|
|
// 0 X
|
|
|
|
if let Some(rem) = rem {
|
|
*rem = <$ty>::from(urem!(n.low(), d.low()));
|
|
}
|
|
return <$ty>::from(udiv!(n.low(), d.low()));
|
|
} else {
|
|
// 0 X
|
|
// ---
|
|
// K X
|
|
if let Some(rem) = rem {
|
|
*rem = n;
|
|
}
|
|
return 0;
|
|
};
|
|
}
|
|
|
|
let mut sr;
|
|
let mut q;
|
|
let mut r;
|
|
|
|
if d.low() == 0 {
|
|
if d.high() == 0 {
|
|
// K X
|
|
// ---
|
|
// 0 0
|
|
// NOTE This should be unreachable in safe Rust because the program will panic before
|
|
// this intrinsic is called
|
|
unsafe {
|
|
intrinsics::abort()
|
|
}
|
|
}
|
|
|
|
if n.low() == 0 {
|
|
// K 0
|
|
// ---
|
|
// K 0
|
|
if let Some(rem) = rem {
|
|
*rem = <$ty>::from_parts(0, urem!(n.high(), d.high()));
|
|
}
|
|
return <$ty>::from(udiv!(n.high(), d.high()));
|
|
}
|
|
|
|
// K K
|
|
// ---
|
|
// K 0
|
|
|
|
if d.high().is_power_of_two() {
|
|
if let Some(rem) = rem {
|
|
*rem = <$ty>::from_parts(n.low(), n.high() & (d.high() - 1));
|
|
}
|
|
return <$ty>::from(n.high() >> d.high().trailing_zeros());
|
|
}
|
|
|
|
sr = d.high().leading_zeros().wrapping_sub(n.high().leading_zeros());
|
|
|
|
// D > N
|
|
if sr > <hty!($ty)>::bits() - 2 {
|
|
if let Some(rem) = rem {
|
|
*rem = n;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
sr += 1;
|
|
|
|
// 1 <= sr <= <hty!($ty)>::bits() - 1
|
|
q = n << (<$ty>::bits() - sr);
|
|
r = n >> sr;
|
|
} else if d.high() == 0 {
|
|
// K X
|
|
// ---
|
|
// 0 K
|
|
if d.low().is_power_of_two() {
|
|
if let Some(rem) = rem {
|
|
*rem = <$ty>::from(n.low() & (d.low() - 1));
|
|
}
|
|
|
|
if d.low() == 1 {
|
|
return n;
|
|
} else {
|
|
let sr = d.low().trailing_zeros();
|
|
return n >> sr;
|
|
};
|
|
}
|
|
|
|
sr = 1 + <hty!($ty)>::bits() + d.low().leading_zeros() - n.high().leading_zeros();
|
|
|
|
// 2 <= sr <= u64::bits() - 1
|
|
q = n << (<$ty>::bits() - sr);
|
|
r = n >> sr;
|
|
} else {
|
|
// K X
|
|
// ---
|
|
// K K
|
|
sr = d.high().leading_zeros().wrapping_sub(n.high().leading_zeros());
|
|
|
|
// D > N
|
|
if sr > <hty!($ty)>::bits() - 1 {
|
|
if let Some(rem) = rem {
|
|
*rem = n;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
sr += 1;
|
|
|
|
// 1 <= sr <= <hty!($ty)>::bits()
|
|
q = n << (<$ty>::bits() - sr);
|
|
r = n >> sr;
|
|
}
|
|
|
|
// Not a special case
|
|
// q and r are initialized with
|
|
// q = n << (u64::bits() - sr)
|
|
// r = n >> sr
|
|
// 1 <= sr <= u64::bits() - 1
|
|
let mut carry = 0;
|
|
|
|
for _ in 0..sr {
|
|
// r:q = ((r:q) << 1) | carry
|
|
r = (r << 1) | (q >> (<$ty>::bits() - 1));
|
|
q = (q << 1) | carry as $ty;
|
|
|
|
// carry = 0
|
|
// if r >= d {
|
|
// r -= d;
|
|
// carry = 1;
|
|
// }
|
|
let s = (d.wrapping_sub(r).wrapping_sub(1)) as os_ty!($ty) >> (<$ty>::bits() - 1);
|
|
carry = (s & 1) as hty!($ty);
|
|
r -= d & s as $ty;
|
|
}
|
|
|
|
if let Some(rem) = rem {
|
|
*rem = r;
|
|
}
|
|
(q << 1) | carry as $ty
|
|
}}
|
|
}
|
|
|
|
/// Returns `n / d` and sets `*rem = n % d`
|
|
#[cfg_attr(not(test), no_mangle)]
|
|
pub extern "C" fn __udivmoddi4(n: u64, d: u64, rem: Option<&mut u64>) -> u64 {
|
|
udivmod_inner!(n, d, rem, u64)
|
|
}
|
|
|
|
macro_rules! udivmodti4 {
|
|
($tyret:ty, $conv:expr) => {
|
|
/// Returns `n / d` and sets `*rem = n % d`
|
|
#[cfg_attr(not(test), no_mangle)]
|
|
pub extern "C" fn __udivmodti4(n: u128, d: u128, rem: Option<&mut u128>) -> $tyret {
|
|
let r = u128_div_mod(n, d, rem);
|
|
($conv)(r)
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Returns `n / d` and sets `*rem = n % d`
|
|
fn u128_div_mod(n: u128, d: u128, rem: Option<&mut u128>) -> u128 {
|
|
udivmod_inner!(n, d, rem, u128)
|
|
}
|
|
|
|
#[cfg(all(windows, target_pointer_width="64"))]
|
|
udivmodti4!(::U64x2, ::conv);
|
|
|
|
#[cfg(not(all(windows, target_pointer_width="64")))]
|
|
udivmodti4!(u128, |i|{ i });
|