Add parser for double

go/asm/asm.go

@@ -158,6 +158,35 @@ func writeSize(n uint32, w *bytes.Buffer) (int, error) {
 	return w.Write(bn[c:])	
 }
 
+func parseSingle(op vm.Opcode, arg Arg, w io.Writer) (int, error) {
+	var rn int
+
+	v := arg.ArgSingle
+	if v == nil {
+		return 0, nil
+	}
+
+	b := bytes.NewBuffer(nil)
+
+	n, err := writeOpcode(op, b)
+	rn += n
+	if  err != nil {
+		return rn, err
+	}
+	
+	n, err = writeSym(v.Sym, b)
+	rn += n
+	if err != nil {
+		return rn, err
+	}
+	
+	if w != nil {
+		rn, err = w.Write(b.Bytes())
+	} else {
+		rn = 0
+	}
+	return rn, err
+}
 
 func parseDisplay(op vm.Opcode, arg Arg, w io.Writer) (int, error) {
 	var rn int
@@ -297,7 +326,14 @@ func Parse(s string, w io.Writer) (int, error) {
 			rn += n
 			continue
 		}
-
+		n, err = parseSingle(op, v.OpArg, w)
+		if err != nil {
+			return n, err
+		}
+		if n > 0 {
+			rn += n
+			continue
+		}
 	}
 	return rn, err
 }

go/asm/asm_test.go

@@ -89,3 +89,24 @@ func TestParseDouble(t *testing.T) {
 		t.Fatalf("expected %x, got %x", expect, rb)
 	}
 }
+
+func TestParseSingle(t *testing.T) {
+	var b []byte
+	b = vm.NewLine(b, vm.MAP, []string{"xyzzy"}, nil, nil)
+	s, err := vm.ToString(b)
+	log.Printf("parsing:\n%s\n", s)
+
+	r := bytes.NewBuffer(nil)
+	n, err := Parse(s, r)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if n != 8 {
+		t.Fatalf("expected 8 byte write count, got %v", n)
+	}
+	rb := r.Bytes()
+	expect := []byte{0x00, vm.MAP, 0x05, 0x78, 0x79, 0x7a, 0x7a, 0x79}
+	if !bytes.Equal(rb, expect) {
+		t.Fatalf("expected %x, got %x", expect, rb)
+	}
+}