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Merge remote-tracking branch 'origin/master' into HEAD

This commit is contained in:
Alex Crichton 2018-08-30 14:13:52 -07:00
parent b5563f79ea cdbad7225f
commit abc9132938
2 changed files with 5 additions and 4 deletions
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6
README.md
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@ -69,13 +69,13 @@ features = ["c"]
### Porting Reminders ### Porting Reminders
1. [Rust][4] and [C][5] have slightly different operator precedence. C evaluates comparisons (`== !=`) before bitwise operations (`& | ^`), while Rust evaluates the other way. 1. [Rust][5a] and [C][5b] have slightly different operator precedence. C evaluates comparisons (`== !=`) before bitwise operations (`& | ^`), while Rust evaluates the other way.
2. C assumes wrapping operations everywhere. Rust panics on overflow when in debug mode. Consider using the [Wrapping][6] type or the explicit [wrapping_*][7] functions where applicable. 2. C assumes wrapping operations everywhere. Rust panics on overflow when in debug mode. Consider using the [Wrapping][6] type or the explicit [wrapping_*][7] functions where applicable.
3. Note [C implicit casts][8], especially integer promotion. Rust is much more explicit about casting, so be sure that any cast which affects the output is ported to the Rust implementation. 3. Note [C implicit casts][8], especially integer promotion. Rust is much more explicit about casting, so be sure that any cast which affects the output is ported to the Rust implementation.
4. Rust has [many functions][9] for integer or floating point manipulation in the standard library. Consider using one of these functions rather than porting a new one. 4. Rust has [many functions][9] for integer or floating point manipulation in the standard library. Consider using one of these functions rather than porting a new one.
[4]: https://doc.rust-lang.org/reference.html#operator-precedence [5a]: https://doc.rust-lang.org/reference/expressions.html#expression-precedence
[5]: http://en.cppreference.com/w/c/language/operator_precedence [5b]: http://en.cppreference.com/w/c/language/operator_precedence
[6]: https://doc.rust-lang.org/core/num/struct.Wrapping.html [6]: https://doc.rust-lang.org/core/num/struct.Wrapping.html
[7]: https://doc.rust-lang.org/std/primitive.i32.html#method.wrapping_add [7]: https://doc.rust-lang.org/std/primitive.i32.html#method.wrapping_add
[8]: http://en.cppreference.com/w/cpp/language/implicit_conversion [8]: http://en.cppreference.com/w/cpp/language/implicit_conversion

3
src/riscv32.rs
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@ -1,7 +1,8 @@
intrinsics! { intrinsics! {
// Implementation from gcc // Implementation from gcc
// https://raw.githubusercontent.com/gcc-mirror/gcc/master/libgcc/config/epiphany/mulsi3.c // https://raw.githubusercontent.com/gcc-mirror/gcc/master/libgcc/config/epiphany/mulsi3.c
pub extern "C" fn __mulsi3(mut a: u32, mut b: u32) -> u32 { pub extern "C" fn __mulsi3(a: u32, b: u32) -> u32 {
let (mut a, mut b) = (a, b);
let mut r: usize = 0; let mut r: usize = 0;
while a > 0 { while a > 0 {