From b276f63892813eb6c4cbd0945437e13afe439e17 Mon Sep 17 00:00:00 2001
From: xuexiansong <s.xue.xian.c@gmail.com>
Date: Wed, 7 Apr 2021 21:47:22 +0800
Subject: [PATCH] Feat(BVM): change op sub (#1869)

---
 protocol/vm/numeric.go      | 13 +++++----
 protocol/vm/numeric_test.go | 67 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 75 insertions(+), 5 deletions(-)

diff --git a/protocol/vm/numeric.go b/protocol/vm/numeric.go
index 72906a16..dce00d10 100644
--- a/protocol/vm/numeric.go
+++ b/protocol/vm/numeric.go
@@ -181,19 +181,22 @@ func opSub(vm *virtualMachine) error {
 	if err != nil {
 		return err
 	}
-	y, err := vm.popInt64(true)
+
+	y, err := vm.popBigInt(true)
 	if err != nil {
 		return err
 	}
-	x, err := vm.popInt64(true)
+
+	x, err := vm.popBigInt(true)
 	if err != nil {
 		return err
 	}
-	res, ok := checked.SubInt64(x, y)
-	if !ok {
+
+	if x.Sub(x, y); x.Sign() < 0 {
 		return ErrRange
 	}
-	return vm.pushInt64(res, true)
+
+	return vm.pushBigInt(x, true)
 }
 
 func opMul(vm *virtualMachine) error {
diff --git a/protocol/vm/numeric_test.go b/protocol/vm/numeric_test.go
index 7517fbba..e66df5dd 100644
--- a/protocol/vm/numeric_test.go
+++ b/protocol/vm/numeric_test.go
@@ -909,6 +909,73 @@ func Test_op1Sub(t *testing.T) {
 	}
 }
 
+func Test_opSub(t *testing.T) {
+	type args struct {
+		vm *virtualMachine
+	}
+	tests := []struct {
+		name    string
+		args    args
+		want    [][]byte
+		wantErr bool
+	}{
+		{
+			name: "Test 2 - 1 = 1",
+			args: args{
+				vm: &virtualMachine{
+					runLimit:  50000,
+					dataStack: [][]byte{{0x02}, {0x01}},
+				},
+			},
+			want:    [][]byte{{0x01}},
+			wantErr: false,
+		},
+		{
+			name: "Test that two bytes number become one byte number",
+			args: args{
+				vm: &virtualMachine{
+					runLimit:  50000,
+					dataStack: [][]byte{{0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}, {0x01}},
+				},
+			},
+			want:    [][]byte{{0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff}},
+			wantErr: false,
+		},
+		{
+			name: "Test for 0 - 1 got error",
+			args: args{
+				vm: &virtualMachine{
+					runLimit:  50000,
+					dataStack: [][]byte{{}, {0x01}},
+				},
+			},
+			want:    nil,
+			wantErr: true,
+		},
+		{
+			name: "Test for -1 - 1 got error",
+			args: args{
+				vm: &virtualMachine{
+					runLimit:  50000,
+					dataStack: [][]byte{mocks.U256NumNegative1, {0x01}},
+				},
+			},
+			want:    nil,
+			wantErr: true,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if err := opSub(tt.args.vm); (err != nil) != tt.wantErr {
+				t.Errorf("op1Sub() error = %v, wantErr %v", err, tt.wantErr)
+			}
+			if !testutil.DeepEqual(tt.args.vm.dataStack, tt.want) {
+				t.Errorf("op1Sub() error, got %v and wantErr %v", tt.args.vm.dataStack, tt.want)
+			}
+		})
+	}
+}
+
 func Test_op2Div(t *testing.T) {
 	type args struct {
 		vm *virtualMachine
-- 
2.11.0