Implement blit instruction

src/lib.rs

@@ -70,6 +70,15 @@ pub enum Instr<'a> {
     /// Loads a value from memory pointed to by source
     /// `(type, source)`
     Load(Type<'a>, Value),
+    /// `(source, destination, n)`
+    ///
+    /// Copy `n` bytes from the source address to the destination address.
+    ///
+    /// n must be a constant value.
+    ///
+    /// ## Minimum supported QBE version
+    /// `1.1`
+    Blit(Value, Value, u64),
 }
 
 impl<'a> fmt::Display for Instr<'a> {
@@ -141,6 +150,7 @@ impl<'a> fmt::Display for Instr<'a> {
 
                 write!(f, "load{} {}", ty, src)
             }
+            Self::Blit(src, dst, n) => write!(f, "blit {}, {}, {}", src, dst, n),
         }
     }
 }

src/tests.rs

@@ -52,6 +52,23 @@ fn block() {
     assert_eq!(lines.next().unwrap(), "\tret %foo");
 }
 
+#[test]
+fn instr_blit() {
+    let blk = Block {
+        label: "start".into(),
+        statements: vec![Statement::Volatile(Instr::Blit(
+            Value::Temporary("src".into()),
+            Value::Temporary("dst".into()),
+            4,
+        ))],
+    };
+
+    let formatted = format!("{}", blk);
+    let mut lines = formatted.lines();
+    assert_eq!(lines.next().unwrap(), "@start");
+    assert_eq!(lines.next().unwrap(), "\tblit %src, %dst, 4");
+}
+
 #[test]
 fn function() {
     let func = Function {