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solve overflow of left arithmetic shift (#518)

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This commit is contained in:
Mark Thom
2020-05-17 12:20:22 -06:00
parent 2c4a0cf65b
commit 9f3351469d
1 changed files with 8 additions and 25 deletions
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33
src/prolog/machine/arithmetic_ops.rs
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@@ -722,18 +722,12 @@ impl MachineState {
match (n1, n2) { match (n1, n2) {
(Number::Fixnum(n1), Number::Fixnum(n2)) => { (Number::Fixnum(n1), Number::Fixnum(n2)) => {
if let Ok(n2) = u32::try_from(n2) {
if let Some(result) = n1.checked_shr(n2) {
return Ok(Number::from(result));
}
}
let n1 = Integer::from(n1); let n1 = Integer::from(n1);
let n2 = Integer::from(n2);
match n2.to_u32() { if let Ok(n2) = u32::try_from(n2) {
Some(n2) => Ok(Number::from(n1 >> n2)), return Ok(Number::from(n1 >> n2));
_ => Ok(Number::from(n1 >> u32::max_value())), } else {
return Ok(Number::from(n1 >> u32::max_value()));
} }
} }
(Number::Fixnum(n1), Number::Integer(n2)) => { (Number::Fixnum(n1), Number::Integer(n2)) => {
@@ -780,23 +774,12 @@ impl MachineState {
match (n1, n2) { match (n1, n2) {
(Number::Fixnum(n1), Number::Fixnum(n2)) => { (Number::Fixnum(n1), Number::Fixnum(n2)) => {
if let Ok(n2) = u32::try_from(n2) {
if n2 < 63 {
if let Some(result) = n1.checked_shl(n2) {
return Ok(Number::from(result));
}
} else {
let n1 = Integer::from(n1);
return Ok(Number::from(n1 << n2));
}
}
let n1 = Integer::from(n1); let n1 = Integer::from(n1);
let n2 = Integer::from(n2);
match n2.to_u32() { if let Ok(n2) = u32::try_from(n2) {
Some(n2) => Ok(Number::from(n1 << n2)), return Ok(Number::from(n1 << n2));
_ => Ok(Number::from(n1 << u32::max_value())), } else {
return Ok(Number::from(n1 << u32::max_value()));
} }
} }
(Number::Fixnum(n1), Number::Integer(n2)) => { (Number::Fixnum(n1), Number::Integer(n2)) => {