Add sqrt instruction

vm/ophandler.go

@@ -1,5 +1,7 @@
 package vm
 
+import "math"
+
 type opHandler func(*State, *Instruction)
 
 var opHandlers = map[OpCodeType]opHandler{
@@ -42,6 +44,8 @@ var opHandlers = map[OpCodeType]opHandler{
 	OpReturn:        (*State).handleReturn,
 	OpReturnIfTrue:  (*State).handleReturnIfTrue,
 	OpReturnIfFalse: (*State).handleReturnIfFalse,
+
+	OpSqrt: (*State).handleSqrt,
 }
 
 func (state *State) handleNoOp(instr *Instruction) {
@@ -232,3 +236,8 @@ func (state *State) handleReturnIfFalse(instr *Instruction) {
 		state.handleReturn(instr)
 	}
 }
+
+func (state *State) handleSqrt(instr *Instruction) {
+	in := state.readUnsigned(instr.Operands[0])
+	state.writeUnsigned(instr.Operands[0], uint64(math.Round(math.Sqrt(float64(in)))))
+}