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Macro-ify udivmod

This commit is contained in:
est31 2017-01-05 02:22:44 +01:00
parent 1e27c3f937
commit 8fe50d813c
3 changed files with 163 additions and 141 deletions
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15
src/int/mod.rs
View File

@ -1,3 +1,14 @@
macro_rules! hty {
($ty:ty) => {
<$ty as LargeInt>::HighHalf
}
}
macro_rules! os_ty {
($ty:ty) => {
<$ty as Int>::OtherSign
}
}
pub mod mul;
pub mod sdiv;
@ -6,6 +17,8 @@ pub mod udiv;
/// Trait for some basic operations on integers
pub trait Int {
/// Type with the same width but other signedness
type OtherSign;
/// Returns the bitwidth of the int type
fn bits() -> u32;
}
@ -13,11 +26,13 @@ pub trait Int {
macro_rules! int_impl {
($ity:ty, $sty:ty, $bits:expr) => {
impl Int for $ity {
type OtherSign = $sty;
fn bits() -> u32 {
$bits
}
}
impl Int for $sty {
type OtherSign = $ity;
fn bits() -> u32 {
$bits
}

16
src/int/mul.rs
View File

@ -2,7 +2,7 @@ use int::LargeInt;
use int::Int;
macro_rules! mul {
($intrinsic:ident: $ty:ty, $tyh:ty) => {
($intrinsic:ident: $ty:ty) => {
/// Returns `a * b`
#[cfg_attr(not(test), no_mangle)]
pub extern "C" fn $intrinsic(a: $ty, b: $ty) -> $ty {
@ -13,15 +13,15 @@ macro_rules! mul {
low &= lower_mask;
t += (a.low() >> half_bits).wrapping_mul(b.low() & lower_mask);
low += (t & lower_mask) << half_bits;
let mut high = (t >> half_bits) as $tyh;
let mut high = (t >> half_bits) as hty!($ty);
t = low >> half_bits;
low &= lower_mask;
t += (b.low() >> half_bits).wrapping_mul(a.low() & lower_mask);
low += (t & lower_mask) << half_bits;
high += (t >> half_bits) as $tyh;
high += (a.low() >> half_bits).wrapping_mul(b.low() >> half_bits) as $tyh;
high = high.wrapping_add(a.high().wrapping_mul(b.low() as $tyh))
.wrapping_add((a.low() as $tyh).wrapping_mul(b.high()));
high += (t >> half_bits) as hty!($ty);
high += (a.low() >> half_bits).wrapping_mul(b.low() >> half_bits) as hty!($ty);
high = high.wrapping_add(a.high().wrapping_mul(b.low() as hty!($ty)))
.wrapping_add((a.low() as hty!($ty)).wrapping_mul(b.high()));
<$ty>::from_parts(low, high)
}
}
@ -73,9 +73,9 @@ macro_rules! mulo {
}
#[cfg(not(all(feature = "c", target_arch = "x86")))]
mul!(__muldi3: u64, u32);
mul!(__muldi3: u64);
mul!(__multi3: i128, i64);
mul!(__multi3: i128);
mulo!(__mulosi4: i32);
mulo!(__mulodi4: i64);

55
src/int/udiv.rs
View File

@ -114,9 +114,9 @@ pub extern "C" fn __umoddi3(a: u64, b: u64) -> u64 {
rem
}
/// 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 {
macro_rules! udivmod_inner {
($n:expr, $d:expr, $rem:expr, $ty:ty) => {{
let (n, d, rem) = ($n, $d, $rem);
// NOTE X is unknown, K != 0
if n.high() == 0 {
if d.high() == 0 {
@ -125,9 +125,9 @@ pub extern "C" fn __udivmoddi4(n: u64, d: u64, rem: Option<&mut u64>) -> u64 {
// 0 X
if let Some(rem) = rem {
*rem = u64::from(urem!(n.low(), d.low()));
*rem = <$ty>::from(urem!(n.low(), d.low()));
}
return u64::from(udiv!(n.low(), d.low()));
return <$ty>::from(udiv!(n.low(), d.low()));
} else {
// 0 X
// ---
@ -160,9 +160,9 @@ pub extern "C" fn __udivmoddi4(n: u64, d: u64, rem: Option<&mut u64>) -> u64 {
// ---
// K 0
if let Some(rem) = rem {
*rem = u64::from_parts(0, urem!(n.high(), d.high()));
*rem = <$ty>::from_parts(0, urem!(n.high(), d.high()));
}
return u64::from(udiv!(n.high(), d.high()));
return <$ty>::from(udiv!(n.high(), d.high()));
}
// K K
@ -171,15 +171,15 @@ pub extern "C" fn __udivmoddi4(n: u64, d: u64, rem: Option<&mut u64>) -> u64 {
if d.high().is_power_of_two() {
if let Some(rem) = rem {
*rem = u64::from_parts(n.low(), n.high() & (d.high() - 1));
*rem = <$ty>::from_parts(n.low(), n.high() & (d.high() - 1));
}
return u64::from(n.high() >> d.high().trailing_zeros());
return <$ty>::from(n.high() >> d.high().trailing_zeros());
}
sr = d.high().leading_zeros().wrapping_sub(n.high().leading_zeros());
// D > N
if sr > u32::bits() - 2 {
if sr > <hty!($ty)>::bits() - 2 {
if let Some(rem) = rem {
*rem = n;
}
@ -188,8 +188,8 @@ pub extern "C" fn __udivmoddi4(n: u64, d: u64, rem: Option<&mut u64>) -> u64 {
sr += 1;
// 1 <= sr <= u32::bits() - 1
q = n << (u64::bits() - sr);
// 1 <= sr <= <hty!($ty)>::bits() - 1
q = n << (<$ty>::bits() - sr);
r = n >> sr;
} else if d.high() == 0 {
// K X
@ -197,7 +197,7 @@ pub extern "C" fn __udivmoddi4(n: u64, d: u64, rem: Option<&mut u64>) -> u64 {
// 0 K
if d.low().is_power_of_two() {
if let Some(rem) = rem {
*rem = u64::from(n.low() & (d.low() - 1));
*rem = <$ty>::from(n.low() & (d.low() - 1));
}
if d.low() == 1 {
@ -208,10 +208,10 @@ pub extern "C" fn __udivmoddi4(n: u64, d: u64, rem: Option<&mut u64>) -> u64 {
};
}
sr = 1 + u32::bits() + d.low().leading_zeros() - n.high().leading_zeros();
sr = 1 + <hty!($ty)>::bits() + d.low().leading_zeros() - n.high().leading_zeros();
// 2 <= sr <= u64::bits() - 1
q = n << (u64::bits() - sr);
q = n << (<$ty>::bits() - sr);
r = n >> sr;
} else {
// K X
@ -220,7 +220,7 @@ pub extern "C" fn __udivmoddi4(n: u64, d: u64, rem: Option<&mut u64>) -> u64 {
sr = d.high().leading_zeros().wrapping_sub(n.high().leading_zeros());
// D > N
if sr > u32::bits() - 1 {
if sr > <hty!($ty)>::bits() - 1 {
if let Some(rem) = rem {
*rem = n;
}
@ -229,8 +229,8 @@ pub extern "C" fn __udivmoddi4(n: u64, d: u64, rem: Option<&mut u64>) -> u64 {
sr += 1;
// 1 <= sr <= u32::bits()
q = n << (u64::bits() - sr);
// 1 <= sr <= <hty!($ty)>::bits()
q = n << (<$ty>::bits() - sr);
r = n >> sr;
}
@ -243,23 +243,30 @@ pub extern "C" fn __udivmoddi4(n: u64, d: u64, rem: Option<&mut u64>) -> u64 {
for _ in 0..sr {
// r:q = ((r:q) << 1) | carry
r = (r << 1) | (q >> (u64::bits() - 1));
q = (q << 1) | carry as u64;
r = (r << 1) | (q >> (<$ty>::bits() - 1));
q = (q << 1) | carry as $ty;
// carry = 0
// if r >= d {
// r -= d;
// carry = 1;
// }
let s = (d.wrapping_sub(r).wrapping_sub(1)) as i64 >> (u64::bits() - 1);
carry = (s & 1) as u32;
r -= d & s as u64;
let s = (d.wrapping_sub(r).wrapping_sub(1)) as os_ty!($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 u64
(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)
}
#[cfg(test)]