Rewrite the bytecode interpreter in Rust.

1 files changed, 31 insertions, 0 deletions

diff --git a/bytecode/src/value.rs b/bytecode/src/value.rs
new file mode 100644
index 0000000..fbaa128
--- /dev/null
+++ b/bytecode/src/value.rs
@@ -0,0 +1,31 @@
+#[derive(Clone, Copy)]
+pub struct Value(pub u64);
+
+impl Value {
+    pub fn repr(self) -> u64 {
+        let Value(v) = self;
+        v
+    }
+
+    pub fn to_int(self) -> Option<i64> {
+        if self.repr() & 1 == 0 {
+            return None;
+        }
+        Some(self.repr() as i64 >> 1)
+    }
+
+    pub fn from_int(i: i64) -> Value {
+        Value((i as u64) << 1 | 1)
+    }
+
+    pub fn to_pointer(self) -> Option<usize> {
+        if self.repr() == 0 || self.repr() & 7 != 0 {
+            return None;
+        }
+        Some(usize::try_from(self.repr() >> 3).expect("using 32 bits in 2024 LULW"))
+    }
+
+    pub fn from_pointer(p: usize) -> Value {
+        Value(u64::try_from(p).expect("a usize should always fit in a u64... right?") << 3)
+    }
+}