122 lines
3.5 KiB
Rust
122 lines
3.5 KiB
Rust
use Int;
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macro_rules! div {
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($intrinsic:ident: $ty:ty, $uty:ty) => {
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/// Returns `a / b`
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#[cfg_attr(not(test), no_mangle)]
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pub extern "C" fn $intrinsic(a: $ty, b: $ty) -> $ty {
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let s_a = a >> (<$ty>::bits() - 1);
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let s_b = b >> (<$ty>::bits() - 1);
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let a = (a ^ s_a) - s_a;
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let b = (b ^ s_b) - s_b;
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let s = s_a ^ s_b;
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let r = (a as $uty) / (b as $uty);
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(r as $ty ^ s) - s
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}
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}
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}
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macro_rules! mod_ {
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($intrinsic:ident: $ty:ty, $uty:ty) => {
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/// Returns `a % b`
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#[cfg_attr(not(test), no_mangle)]
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pub extern "C" fn $intrinsic(a: $ty, b: $ty) -> $ty {
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let s = b >> (<$ty>::bits() - 1);
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let b = (b ^ s) - s;
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let s = a >> (<$ty>::bits() - 1);
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let a = (a ^ s) - s;
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let r = (a as $uty) % (b as $uty);
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(r as $ty ^ s) - s
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}
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}
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}
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macro_rules! divmod {
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($intrinsic:ident, $div:ident: $ty:ty) => {
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/// Returns `a / b` and sets `*rem = n % d`
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#[cfg_attr(not(test), no_mangle)]
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pub extern "C" fn $intrinsic(a: $ty, b: $ty, rem: &mut $ty) -> $ty {
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let r = $div(a, b);
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*rem = a - (r * b);
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r
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}
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}
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}
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div!(__divsi3: i32, u32);
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div!(__divdi3: i64, u64);
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mod_!(__modsi3: i32, u32);
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mod_!(__moddi3: i64, u64);
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divmod!(__divmodsi4, __divsi3: i32);
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divmod!(__divmoddi4, __divdi3: i64);
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#[cfg(test)]
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mod tests {
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use quickcheck::TestResult;
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use qc::{U32, U64};
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quickcheck!{
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fn divdi3(n: U64, d: U64) -> TestResult {
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let (n, d) = (n.0 as i64, d.0 as i64);
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if d == 0 {
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TestResult::discard()
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} else {
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let q = super::__divdi3(n, d);
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TestResult::from_bool(q == n / d)
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}
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}
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fn moddi3(n: U64, d: U64) -> TestResult {
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let (n, d) = (n.0 as i64, d.0 as i64);
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if d == 0 {
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TestResult::discard()
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} else {
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let r = super::__moddi3(n, d);
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TestResult::from_bool(r == n % d)
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}
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}
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fn divmoddi4(n: U64, d: U64) -> TestResult {
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let (n, d) = (n.0 as i64, d.0 as i64);
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if d == 0 {
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TestResult::discard()
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} else {
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let mut r = 0;
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let q = super::__divmoddi4(n, d, &mut r);
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TestResult::from_bool(q == n / d && r == n % d)
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}
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}
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fn divsi3(n: U32, d: U32) -> TestResult {
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let (n, d) = (n.0 as i32, d.0 as i32);
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if d == 0 {
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TestResult::discard()
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} else {
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let q = super::__divsi3(n, d);
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TestResult::from_bool(q == n / d)
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}
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}
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fn modsi3(n: U32, d: U32) -> TestResult {
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let (n, d) = (n.0 as i32, d.0 as i32);
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if d == 0 {
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TestResult::discard()
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} else {
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let r = super::__modsi3(n, d);
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TestResult::from_bool(r == n % d)
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}
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}
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fn divmodsi4(n: U32, d: U32) -> TestResult {
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let (n, d) = (n.0 as i32, d.0 as i32);
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if d == 0 {
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TestResult::discard()
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} else {
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let mut r = 0;
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let q = super::__divmodsi4(n, d, &mut r);
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TestResult::from_bool(q == n / d && r == n % d)
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}
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}
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}
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}
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