Improved BigInt

builtin_bigint.go

@@ -246,10 +246,10 @@ func (r *Runtime) bigint_asIntN(call FunctionCall) Value {
 	}
 	bigint := toBigInt(call.Argument(1))
 
-	lsh := big.NewInt(2).Lsh(big.NewInt(1), uint(bits))
-	mod := new(big.Int).Mod(bigint.i, lsh)
-	if bits > 0 && mod.Cmp(big.NewInt(2).Lsh(big.NewInt(1), uint(bits-1))) >= 0 {
-		return valueBigInt{mod.Sub(mod, lsh)}
+	twoToBits := new(big.Int).Lsh(big.NewInt(1), uint(bits))
+	mod := new(big.Int).Mod(bigint.i, twoToBits)
+	if bits > 0 && mod.Cmp(new(big.Int).Lsh(big.NewInt(1), uint(bits-1))) >= 0 {
+		return valueBigInt{mod.Sub(mod, twoToBits)}
 	} else {
 		return valueBigInt{mod}
 	}
@@ -264,7 +264,7 @@ func (r *Runtime) bigint_asUintN(call FunctionCall) Value {
 		panic(r.NewTypeError("Invalid value: not (convertible to) a safe integer"))
 	}
 	bigint := toBigInt(call.Argument(1))
-	return valueBigInt{new(big.Int).Mod(bigint.i, big.NewInt(2).Lsh(big.NewInt(1), uint(bits)))}
+	return valueBigInt{new(big.Int).Mod(bigint.i, new(big.Int).Lsh(big.NewInt(1), uint(bits)))}
 }
 
 var bigintTemplate *objectTemplate

builtin_typedarrays.go

@@ -396,7 +396,7 @@ func (r *Runtime) dataViewProto_setUint32(call FunctionCall) Value {
 func (r *Runtime) dataViewProto_setBigInt64(call FunctionCall) Value {
 	if dv, ok := r.toObject(call.This).self.(*dataViewObject); ok {
 		idxVal := r.toIndex(call.Argument(0))
-		val := toBigInt(call.Argument(1)).i
+		val := toBigInt64(call.Argument(1))
 		idx, bo := dv.getIdxAndByteOrder(idxVal, call.Argument(2), 8)
 		dv.viewedArrayBuf.setBigInt64(idx, val, bo)
 		return _undefined
@@ -407,7 +407,7 @@ func (r *Runtime) dataViewProto_setBigInt64(call FunctionCall) Value {
 func (r *Runtime) dataViewProto_setBigUint64(call FunctionCall) Value {
 	if dv, ok := r.toObject(call.This).self.(*dataViewObject); ok {
 		idxVal := r.toIndex(call.Argument(0))
-		val := toBigInt(call.Argument(1)).i
+		val := toBigUint64(call.Argument(1))
 		idx, bo := dv.getIdxAndByteOrder(idxVal, call.Argument(2), 8)
 		dv.viewedArrayBuf.setBigUint64(idx, val, bo)
 		return _undefined

typedarrays.go

@@ -648,9 +648,13 @@ func (a *bigInt64Array) get(idx int) Value {
 
 func toBigInt64(v Value) *big.Int {
 	n := toBigInt(v).i
-	int64bit := new(big.Int).Mod(n, big.NewInt(2).Exp(big.NewInt(2), big.NewInt(64), nil))
-	if int64bit.Cmp(big.NewInt(2).Exp(big.NewInt(2), big.NewInt(63), nil)) >= 0 {
-		return int64bit.Sub(int64bit, big.NewInt(2).Exp(big.NewInt(2), big.NewInt(64), nil))
+
+	twoTo64 := new(big.Int).Lsh(big.NewInt(1), 64)
+	twoTo63 := new(big.Int).Lsh(big.NewInt(1), 63)
+
+	int64bit := new(big.Int).Mod(n, twoTo64)
+	if int64bit.Cmp(twoTo63) >= 0 {
+		return int64bit.Sub(int64bit, twoTo64)
 	}
 	return int64bit
 }
@@ -717,7 +721,7 @@ func (a *bigUint64Array) get(idx int) Value {
 
 func toBigUint64(v Value) *big.Int {
 	n := toBigInt(v).i
-	return new(big.Int).Mod(n, big.NewInt(2).Exp(big.NewInt(2), big.NewInt(64), nil))
+	return new(big.Int).Mod(n, new(big.Int).Lsh(big.NewInt(1), 64))
 }
 
 func (a *bigUint64Array) set(idx int, value Value) {

vm.go

@@ -1542,7 +1542,7 @@ func (_mod) exec(vm *vm) {
 			case right.i.Cmp(big.NewInt(0)) == 0:
 				panic(vm.r.newError(vm.r.getRangeError(), "Division by zero"))
 			case left.i.Cmp(big.NewInt(0)) < 0:
-				abs := left.i.Abs(left.i)
+				abs := new(big.Int).Abs(left.i)
 				v := new(big.Int).Mod(abs, right.i)
 				result = valueBigInt{v.Neg(v)}
 			default:
@@ -4463,7 +4463,7 @@ func cmp(px, py Value) Value {
 				nx, _ := nx.Int(nil)
 				ret = nx.Cmp(ny.i) < 0
 			} else {
-				ret = nx.Cmp(big.NewFloat(0).SetInt(ny.i)) < 0
+				ret = nx.Cmp(new(big.Float).SetInt(ny.i)) < 0
 			}
 			goto end
 		}
@@ -4484,7 +4484,7 @@ func cmp(px, py Value) Value {
 				ny, _ := ny.Int(nil)
 				ret = nx.i.Cmp(ny) < 0
 			} else {
-				ret = big.NewFloat(0).SetInt(nx.i).Cmp(ny) < 0
+				ret = new(big.Float).SetInt(nx.i).Cmp(ny) < 0
 			}
 			goto end
 		case valueBigInt: