Port udiv to the `intrinsics!` macro
This commit is contained in:
Alex Crichton
parent
7886ae275b
commit
d17042106f
274
src/int/udiv.rs
274
src/int/udiv.rs
|
|
@ -1,141 +1,7 @@
|
|||
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, $rem);
|
||||
|
|
@ -285,30 +151,120 @@ macro_rules! udivmod_inner {
|
|||
}}
|
||||
}
|
||||
|
||||
/// Returns `n / d` and sets `*rem = n % d`
|
||||
#[cfg_attr(not(test), no_mangle)]
|
||||
pub extern "C" fn __udivmoddi4(n: u64, d: u64, rem: Option<&mut u64>) -> u64 {
|
||||
udivmod_inner!(n, d, rem, u64)
|
||||
}
|
||||
|
||||
macro_rules! udivmodti4 {
|
||||
($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)
|
||||
intrinsics! {
|
||||
#[use_c_shim_if(all(target_arch = "arm",
|
||||
not(target_os = "ios"),
|
||||
not(thumbv6m)))]
|
||||
/// Returns `n / d`
|
||||
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
|
||||
}
|
||||
|
||||
#[use_c_shim_if(all(target_arch = "arm", not(target_os = "ios")))]
|
||||
/// Returns `n % d`
|
||||
pub extern "C" fn __umodsi3(n: u32, d: u32) -> u32 {
|
||||
let q = __udivsi3(n, d);
|
||||
n - q * d
|
||||
}
|
||||
|
||||
#[use_c_shim_if(all(target_arch = "arm",
|
||||
not(target_os = "ios"),
|
||||
not(thumbv6m)))]
|
||||
/// Returns `n / d` and sets `*rem = n % d`
|
||||
pub extern "C" fn __udivmodsi4(n: u32, d: u32, rem: Option<&mut u32>) -> u32 {
|
||||
let q = __udivsi3(n, d);
|
||||
if let Some(rem) = rem {
|
||||
*rem = n - (q * d);
|
||||
}
|
||||
q
|
||||
}
|
||||
|
||||
#[use_c_shim_if(target_arch = "x86")]
|
||||
/// Returns `n / d`
|
||||
pub extern "C" fn __udivdi3(n: u64, d: u64) -> u64 {
|
||||
__udivmoddi4(n, d, None)
|
||||
}
|
||||
|
||||
#[use_c_shim_if(target_arch = "x86")]
|
||||
/// Returns `n % d`
|
||||
pub extern "C" fn __umoddi3(n: u64, d: u64) -> u64 {
|
||||
let mut rem = 0;
|
||||
__udivmoddi4(n, d, Some(&mut rem));
|
||||
rem
|
||||
}
|
||||
|
||||
#[win64_128bit_abi_hack]
|
||||
/// Returns `n / d`
|
||||
pub extern "C" fn __udivti3(n: u128, d: u128) -> u128 {
|
||||
__udivmodti4(n, d, None)
|
||||
}
|
||||
|
||||
#[win64_128bit_abi_hack]
|
||||
/// Returns `n % d`
|
||||
pub extern "C" fn __umodti3(n: u128, d: u128) -> u128 {
|
||||
let mut rem = 0;
|
||||
__udivmodti4(n, d, Some(&mut rem));
|
||||
rem
|
||||
}
|
||||
|
||||
/// Returns `n / d` and sets `*rem = n % d`
|
||||
pub extern "C" fn __udivmoddi4(n: u64, d: u64, rem: Option<&mut u64>) -> u64 {
|
||||
udivmod_inner!(n, d, rem, u64)
|
||||
}
|
||||
|
||||
#[win64_128bit_abi_hack]
|
||||
/// Returns `n / d` and sets `*rem = n % d`
|
||||
pub extern "C" fn __udivmodti4(n: u128,
|
||||
d: u128,
|
||||
rem: Option<&mut u128>) -> u128 {
|
||||
udivmod_inner!(n, d, rem, u128)
|
||||
}
|
||||
}
|
||||
|
||||
/// 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 });
|
||||
|
|
|
|||
Loading…
Reference in New Issue