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add forwarding bit to all heap cells (#1384)

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This commit is contained in:
Mark Thom
2022-04-05 20:13:17 -06:00
parent 8c99d748e2
commit f3167f6b5f
9 changed files with 91 additions and 110 deletions
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13
src/parser/ast.rs
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@@ -466,7 +466,8 @@ pub enum Fixity {
#[repr(u64)]
#[derive(Copy, Clone, Debug, Hash, PartialEq, Eq)]
pub struct Fixnum {
num: B57,
num: B56,
#[allow(unused)] f: bool,
#[allow(unused)] m: bool,
#[allow(unused)] tag: B6,
}
@@ -475,7 +476,7 @@ impl Fixnum {
#[inline]
pub fn build_with(num: i64) -> Self {
Fixnum::new()
.with_num(u64::from_ne_bytes(num.to_ne_bytes()) & ((1 << 57) - 1))
.with_num(u64::from_ne_bytes(num.to_ne_bytes()) & ((1 << 56) - 1))
.with_tag(HeapCellValueTag::Fixnum as u8)
.with_m(false)
//num as u64).with__m(false)
@@ -483,14 +484,14 @@ impl Fixnum {
#[inline]
pub fn build_with_checked(num: i64) -> Result<Self, OutOfBounds> {
const UPPER_BOUND: i64 = (1 << 56) - 1;
const LOWER_BOUND: i64 = -(1 << 56);
const UPPER_BOUND: i64 = (1 << 55) - 1;
const LOWER_BOUND: i64 = -(1 << 55);
if LOWER_BOUND <= num && num <= UPPER_BOUND {
Ok(Fixnum::new()
.with_m(false)
.with_tag(HeapCellValueTag::Fixnum as u8)
.with_num(u64::from_ne_bytes(num.to_ne_bytes()) & ((1 << 57) - 1))) //num as u64 & ((1 << 57) - 1)))
.with_num(u64::from_ne_bytes(num.to_ne_bytes()) & ((1 << 56) - 1)))
} else {
Err(OutOfBounds {})
}
@@ -499,7 +500,7 @@ impl Fixnum {
#[inline]
pub fn get_num(self) -> i64 {
let n = self.num() as i64;
let (n, overflowed) = (n << 7).overflowing_shr(7); // sign-extend the 57-bit signed fixnum.
let (n, overflowed) = (n << 8).overflowing_shr(8);
debug_assert_eq!(overflowed, false);
n
}