M-Labs
/
compiler-builtins-zynq
8
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

Use traits instead of macros for shift intrinsics 

This is an attempt to tidy up the definition of intrinsics by making them more
rust-like at the definition site and using traits instead of macros for the
definition. Additionally the helper macro, `intrinsics!`, now fills in a
definition for #[cfg]'d off intrinsics when compiling with C code
master
Alex Crichton 2017-06-22 22:03:07 -07:00
parent a1377878c6
commit 2f2bb32e40
4 changed files with 166 additions and 61 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

43
src/int/mod.rs
View File

@ -1,3 +1,5 @@
use core::ops;
macro_rules! hty {
($ty:ty) => {
<$ty as LargeInt>::HighHalf
@ -16,15 +18,25 @@ pub mod shift;
pub mod udiv;
/// Trait for some basic operations on integers
pub trait Int {
pub trait Int:
Copy +
PartialEq +
ops::Shl<u32, Output = Self> +
ops::Shr<u32, Output = Self> +
ops::BitOr<Output = Self> +
// ops::BitAnd<Output = Self> +
{
/// Type with the same width but other signedness
type OtherSign;
type OtherSign: Int;
/// Unsigned version of Self
type UnsignedInt;
type UnsignedInt: Int;
/// Returns the bitwidth of the int type
fn bits() -> u32;
/// Returns the zero representation of this number
fn zero() -> Self;
/// Extracts the sign from self and returns a tuple.
///
/// # Examples
@ -36,6 +48,9 @@ pub trait Int {
/// assert_eq!(u, 25_u32);
/// ```
fn extract_sign(self) -> (bool, Self::UnsignedInt);
/// Convert to a signed representation
fn unsigned(self) -> Self::UnsignedInt;
}
macro_rules! int_impl {
@ -44,6 +59,10 @@ macro_rules! int_impl {
type OtherSign = $ity;
type UnsignedInt = $uty;
fn zero() -> Self {
0
}
fn bits() -> u32 {
$bits
}
@ -51,6 +70,10 @@ macro_rules! int_impl {
fn extract_sign(self) -> (bool, $uty) {
(false, self)
}
fn unsigned(self) -> $uty {
self
}
}
impl Int for $ity {
@ -61,6 +84,10 @@ macro_rules! int_impl {
$bits
}
fn zero() -> Self {
0
}
fn extract_sign(self) -> (bool, $uty) {
if self < 0 {
(true, (!(self as $uty)).wrapping_add(1))
@ -68,6 +95,10 @@ macro_rules! int_impl {
(false, self as $uty)
}
}
fn unsigned(self) -> $uty {
self as $uty
}
}
}
}
@ -77,9 +108,9 @@ int_impl!(i64, u64, 64);
int_impl!(i128, u128, 128);
/// Trait to convert an integer to/from smaller parts
pub trait LargeInt {
type LowHalf;
type HighHalf;
pub trait LargeInt: Int {
type LowHalf: Int;
type HighHalf: Int;
fn low(self) -> Self::LowHalf;
fn high(self) -> Self::HighHalf;

130
src/int/shift.rs
View File

@ -1,74 +1,94 @@
use int::{Int, LargeInt};
macro_rules! ashl {
($intrinsic:ident: $ty:ty) => {
/// Returns `a << b`, requires `b < $ty::bits()`
#[cfg_attr(not(test), no_mangle)]
#[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 $intrinsic(a: $ty, b: u32) -> $ty {
let half_bits = <$ty>::bits() / 2;
if b & half_bits != 0 {
<$ty>::from_parts(0, a.low() << (b - half_bits))
} else if b == 0 {
a
} else {
<$ty>::from_parts(a.low() << b, (a.high() << b) | (a.low() >> (half_bits - b)))
}
trait Ashl: Int + LargeInt {
/// Returns `a << b`, requires `b < $ty::bits()`
fn ashl(self, offset: u32) -> Self
where Self: LargeInt<HighHalf = <Self as LargeInt>::LowHalf>,
{
let half_bits = Self::bits() / 2;
if offset & half_bits != 0 {
Self::from_parts(Int::zero(), self.low() << (offset - half_bits))
} else if offset == 0 {
self
} else {
Self::from_parts(self.low() << offset,
(self.high() << offset) |
(self.low() >> (half_bits - offset)))
}
}
}
macro_rules! ashr {
($intrinsic:ident: $ty:ty) => {
/// Returns arithmetic `a >> b`, requires `b < $ty::bits()`
#[cfg_attr(not(test), no_mangle)]
#[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 $intrinsic(a: $ty, b: u32) -> $ty {
let half_bits = <$ty>::bits() / 2;
if b & half_bits != 0 {
<$ty>::from_parts((a.high() >> (b - half_bits)) as <$ty as LargeInt>::LowHalf,
a.high() >> (half_bits - 1))
} else if b == 0 {
a
} else {
let high_unsigned = a.high() as <$ty as LargeInt>::LowHalf;
<$ty>::from_parts((high_unsigned << (half_bits - b)) | (a.low() >> b),
a.high() >> b)
}
impl Ashl for u64 {}
impl Ashl for u128 {}
trait Ashr: Int + LargeInt {
/// Returns arithmetic `a >> b`, requires `b < $ty::bits()`
fn ashr(self, offset: u32) -> Self
where Self: LargeInt<LowHalf = <<Self as LargeInt>::HighHalf as Int>::UnsignedInt>,
{
let half_bits = Self::bits() / 2;
if offset & half_bits != 0 {
Self::from_parts((self.high() >> (offset - half_bits)).unsigned(),
self.high() >> (half_bits - 1))
} else if offset == 0 {
self
} else {
let high_unsigned = self.high().unsigned();
Self::from_parts((high_unsigned << (half_bits - offset)) | (self.low() >> offset),
self.high() >> offset)
}
}
}
macro_rules! lshr {
($intrinsic:ident: $ty:ty) => {
/// Returns logical `a >> b`, requires `b < $ty::bits()`
#[cfg_attr(not(test), no_mangle)]
pub extern "C" fn $intrinsic(a: $ty, b: u32) -> $ty {
let half_bits = <$ty>::bits() / 2;
if b & half_bits != 0 {
<$ty>::from_parts(a.high() >> (b - half_bits), 0)
} else if b == 0 {
a
} else {
<$ty>::from_parts((a.high() << (half_bits - b)) | (a.low() >> b), a.high() >> b)
}
impl Ashr for i64 {}
impl Ashr for i128 {}
trait Lshr: Int + LargeInt {
/// Returns logical `a >> b`, requires `b < $ty::bits()`
fn lshr(self, offset: u32) -> Self
where Self: LargeInt<HighHalf = <Self as LargeInt>::LowHalf>,
{
let half_bits = Self::bits() / 2;
if offset & half_bits != 0 {
Self::from_parts(self.high() >> (offset - half_bits), Int::zero())
} else if offset == 0 {
self
} else {
Self::from_parts((self.high() << (half_bits - offset)) |
(self.low() >> offset),
self.high() >> offset)
}
}
}
#[cfg(not(all(feature = "c", target_arch = "x86")))]
ashl!(__ashldi3: u64);
impl Lshr for u64 {}
impl Lshr for u128 {}
ashl!(__ashlti3: u128);
intrinsics! {
#[cfg(not(all(feature = "c", target_arch = "x86")))]
pub extern "C" fn __ashldi3(a: u64, b: u32) -> u64 {
a.ashl(b)
}
#[cfg(not(all(feature = "c", target_arch = "x86")))]
ashr!(__ashrdi3: i64);
pub extern "C" fn __ashlti3(a: u128, b: u32) -> u128 {
a.ashl(b)
}
ashr!(__ashrti3: i128);
#[cfg(not(all(feature = "c", target_arch = "x86")))]
pub extern "C" fn __ashrdi3(a: i64, b: u32) -> i64 {
a.ashr(b)
}
#[cfg(not(all(feature = "c", target_arch = "x86")))]
lshr!(__lshrdi3: u64);
pub extern "C" fn __ashrti3(a: i128, b: u32) -> i128 {
a.ashr(b)
}
lshr!(__lshrti3: u128);
#[cfg(not(all(feature = "c", target_arch = "x86")))]
pub extern "C" fn __lshrdi3(a: u64, b: u32) -> u64 {
a.lshr(b)
}
pub extern "C" fn __lshrti3(a: u128, b: u32) -> u128 {
a.lshr(b)
}
}

3
src/lib.rs
View File

@ -99,6 +99,9 @@ fn sconv(i: i128) -> U64x2 {
#[cfg(test)]
extern crate core;
#[macro_use]
mod macros;
pub mod int;
pub mod float;

51
src/macros.rs Normal file
View File

@ -0,0 +1,51 @@
macro_rules! intrinsics {
() => ();
(
#[cfg(not(all(feature = "c", $($cfg_clause:tt)*)))]
$(#[$attr:meta])*
pub extern $abi:tt fn $name:ident( $($argname:ident: $ty:ty),* ) -> $ret:ty {
$($body:tt)*
}
$($rest:tt)*
) => (
#[cfg(all(feature = "c", not($($cfg_clause)*)))]
$(#[$attr])*
pub extern $abi fn $name( $($argname: $ty),* ) -> $ret {
extern $abi {
fn $name($($argname: $ty),*) -> $ret;
}
unsafe {
$name($($argname),*)
}
}
#[cfg(not(all(feature = "c", not($($cfg_clause)*))))]
intrinsics! {
$(#[$attr])*
pub extern $abi fn $name( $($argname: $ty),* ) -> $ret {
$($body)*
}
}
intrinsics!($($rest)*);
);
(
$(#[$attr:meta])*
pub extern $abi:tt fn $name:ident( $($argname:ident: $ty:ty),* ) -> $ret:ty {
$($body:tt)*
}
$($rest:tt)*
) => (
$(#[$attr])*
#[cfg_attr(not(test), no_mangle)]
pub extern $abi fn $name( $($argname: $ty),* ) -> $ret {
$($body)*
}
intrinsics!($($rest)*);
);
}