Merge pull request #2323 from CortexFoundation/dev

optimized push2

Author: ucwong

core/vm/instructions.go

@@ -1216,6 +1216,23 @@ func opPush1(pc *uint64, interpreter *CVMInterpreter, scope *ScopeContext) ([]by
 	return nil, nil
 }
 
+// opPush2 is a specialized version of pushN
+func opPush2(pc *uint64, interpreter *CVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	var (
+		codeLen = uint64(len(scope.Contract.Code))
+		integer = new(uint256.Int)
+	)
+	if *pc+2 < codeLen {
+		scope.Stack.push(integer.SetBytes2(scope.Contract.Code[*pc+1 : *pc+3]))
+	} else if *pc+1 < codeLen {
+		scope.Stack.push(integer.SetUint64(uint64(scope.Contract.Code[*pc+1]) << 8))
+	} else {
+		scope.Stack.push(integer.Clear())
+	}
+	*pc += 2
+	return nil, nil
+}
+
 // make push instruction function
 func makePush(size uint64, pushByteSize int) executionFunc {
 	return func(pc *uint64, interpreter *CVMInterpreter, scope *ScopeContext) ([]byte, error) {

core/vm/jump_table.go

@@ -501,7 +501,7 @@ func newFrontierInstructionSet() JumpTable {
 			validateStack: makeStackFunc(0, 1),
 		},
 		PUSH2: {
-			execute:       makePush(2, 2),
+			execute:       opPush2,
 			gasCost:       gasPush,
 			validateStack: makeStackFunc(0, 1),
 		},