Generate random single instructions

gen/operand.go

@@ -0,0 +1,50 @@
+package gen
+
+import "math/rand"
+
+import "github.com/firestuff/subcoding/vm"
+
+func randOperand(t vm.OperandNumericType) *vm.Operand {
+	for {
+		op := &vm.Operand{
+			Type: randOperandType(),
+		}
+
+		switch op.Type {
+		case vm.GlobalMemoryIndex:
+			op.Value = RandBiasedUint64()
+
+		case vm.FunctionMemoryIndex:
+			op.Value = RandBiasedUint64()
+
+		case vm.Literal:
+			switch t {
+			case vm.OperandUnsigned:
+				op.Value = RandBiasedUint64()
+
+			case vm.OperandSigned:
+				op.Value = RandBiasedInt64()
+
+			case vm.OperandSignedOrUnsigned:
+				op.Value = RandBiasedUSint64()
+
+			case vm.OperandReference:
+				// Invalid. Roll the dice again.
+				continue
+			}
+		}
+
+		return op
+	}
+}
+
+var operandTypes = []vm.OperandType{
+	vm.Literal,
+	vm.FunctionMemoryIndex,
+	vm.GlobalMemoryIndex,
+}
+
+func randOperandType() vm.OperandType {
+	// Uniform distribution
+	return operandTypes[rand.Intn(len(operandTypes))]
+}