update Long instruction type to reflect its nature as a special case of Var.2OP

zing/src/encoding/instruction.rs

@@ -16,12 +16,8 @@ pub enum Instruction {
         operand: Operand,
         opcode: Short1OpOpcode,
     },
-    Long2Op {
-        operands: (Operand, Operand),
-        opcode: Long2OpOpcode,
-    },
     Variable2Op {
-        operands: (Operand, Operand),
+        operands: Vec<Operand>,
         opcode: Variable2OpOpcode,
     },
     VariableVarOp {
@@ -122,8 +118,6 @@ make_instruction_type!(Variable2OpOpcode {
     28 Throw,
 });
 
-type Long2OpOpcode = Variable2OpOpcode;
-
 make_instruction_type!(VariableVarOpOpcode {
     0 CallVs,
     1 Storew,
@@ -273,9 +267,9 @@ pub fn decode_instruction(cursor: &mut SimpleCursor) -> Result<Instruction, Inst
             OperandType::SmallConst => Operand::make_small(cursor.read_const().unwrap()),
             OperandType::Var => Operand::make_var(cursor.read_const().unwrap()),
         };
-        let PotentialStoreBranchText { store, branch, text } = decode_store_branch_text::<Long2OpOpcode>(cursor, opcode_num);
+        let PotentialStoreBranchText { store, branch, text } = decode_store_branch_text::<Variable2OpOpcode>(cursor, opcode_num);
-        Long2OpOpcode::from_number(opcode_num, store, branch,text)
+        Variable2OpOpcode::from_number(opcode_num, store, branch,text)
-            .map(|opcode| Instruction::Long2Op { operands: (operand_1, operand_2), opcode })
+            .map(|opcode| Instruction::Variable2Op { operands: vec![operand_1, operand_2], opcode })
     }
 
     fn decode_extended(cursor: &mut SimpleCursor) -> Result<Instruction, InstructionDecodeError> {
@@ -328,22 +322,17 @@ pub fn decode_instruction(cursor: &mut SimpleCursor) -> Result<Instruction, Inst
             VariableVarOpOpcode::from_number(opcode_num, store, branch, text)
                 .map(|opcode| Instruction::VariableVarOp { operands, opcode })
         } else {
+            let mut operands = vec![];
             let &[op_descs] = cursor.read_const().unwrap();
-            let op0 = match (op_descs >> 6) & 0b11 {
+            for i in 0..4 {
-                0b00 => Operand::make_large(cursor.read_const().unwrap()),
+                match (op_descs >> (6 - 2 * i)) & 0b11 {
-                0b01 => Operand::make_small(cursor.read_const().unwrap()),
+                    0b00 => operands.push(Operand::make_large(cursor.read_const().unwrap())),
-                0b10 => Operand::make_var(cursor.read_const().unwrap()),
+                    0b01 => operands.push(Operand::make_small(cursor.read_const().unwrap())),
-                0b11 => return Err(InstructionDecodeError::InsufficientOperands),
+                    0b10 => operands.push(Operand::make_var(cursor.read_const().unwrap())),
-                _ => unreachable!()
+                    0b11 => (),
-            };
-            let op1 = match (op_descs >> 4) & 0b11 {
-                0b00 => Operand::make_large(cursor.read_const().unwrap()),
-                0b01 => Operand::make_small(cursor.read_const().unwrap()),
-                0b10 => Operand::make_var(cursor.read_const().unwrap()),
-                0b11 => return Err(InstructionDecodeError::InsufficientOperands),
                     _ => unreachable!()
                 };
-            let operands = (op0, op1);
+            }
             let PotentialStoreBranchText { store, branch, text } = decode_store_branch_text::<Variable2OpOpcode>(cursor, opcode_num);
             Variable2OpOpcode::from_number(opcode_num, store, branch, text)
                 .map(|opcode| Instruction::Variable2Op { operands, opcode })