now supporting '%' and '/' on Data and in expressions (#151)

p4lang · Jun 20, 2016 · d6ff272 · d6ff272
1 parent 8ce6960
commit d6ff272
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Showing 5 changed files with 74 additions and 2 deletions.
diff --git a/include/bm/bm_sim/data.h b/include/bm/bm_sim/data.h
@@ -232,13 +232,24 @@ class Data {
     export_bytes();
   }
 
-  //! Performs a modulo operation
+  //! Performs a modulo operation. The following needs to be true: \p src1 >= 0
+  //! and \p src2 > 0.
   void mod(const Data &src1, const Data &src2) {
     assert(src1.arith && src2.arith);
+    assert(src1.value >= 0 && src2.value > 0);
     value = src1.value % src2.value;
     export_bytes();
   }
 
+  //! Performs a division operation. The following needs to be true: \p src1 >=
+  //! 0 and \p src2 > 0.
+  void divide(const Data &src1, const Data &src2) {
+    assert(src1.arith && src2.arith);
+    assert(src1.value >= 0 && src2.value > 0);
+    value = src1.value / src2.value;
+    export_bytes();
+  }
+
   //! NC
   void multiply(const Data &src1, const Data &src2) {
     assert(src1.arith && src2.arith);

diff --git a/include/bm/bm_sim/expressions.h b/include/bm/bm_sim/expressions.h
@@ -34,7 +34,7 @@ namespace bm {
 enum class ExprOpcode {
   LOAD_FIELD, LOAD_HEADER, LOAD_BOOL, LOAD_CONST, LOAD_LOCAL,
   LOAD_REGISTER_REF, LOAD_REGISTER_GEN,
-  ADD, SUB, MOD, MUL, SHIFT_LEFT, SHIFT_RIGHT,
+  ADD, SUB, MOD, DIV, MUL, SHIFT_LEFT, SHIFT_RIGHT,
   EQ_DATA, NEQ_DATA, GT_DATA, LT_DATA, GET_DATA, LET_DATA,
   AND, OR, NOT,
   BIT_AND, BIT_OR, BIT_XOR, BIT_NEG,

diff --git a/src/bm_sim/expressions.cpp b/src/bm_sim/expressions.cpp
@@ -41,6 +41,8 @@ ExprOpcodesMap::ExprOpcodesMap() {
     {"load_register_gen", ExprOpcode::LOAD_REGISTER_GEN},
     {"+", ExprOpcode::ADD},
     {"-", ExprOpcode::SUB},
+    {"%", ExprOpcode::MOD},
+    {"/", ExprOpcode::DIV},
     {"*", ExprOpcode::MUL},
     {"<<", ExprOpcode::SHIFT_LEFT},
     {">>", ExprOpcode::SHIFT_RIGHT},
@@ -297,6 +299,20 @@ Expression::eval_(const PHV &phv, ExprType expr_type,
         data_temps_stack.push_back(&data_temps[op.data_dest_index]);
         break;
 
+      case ExprOpcode::MOD:
+        rd = data_temps_stack.back(); data_temps_stack.pop_back();
+        ld = data_temps_stack.back(); data_temps_stack.pop_back();
+        data_temps[op.data_dest_index].mod(*ld, *rd);
+        data_temps_stack.push_back(&data_temps[op.data_dest_index]);
+        break;
+
+      case ExprOpcode::DIV:
+        rd = data_temps_stack.back(); data_temps_stack.pop_back();
+        ld = data_temps_stack.back(); data_temps_stack.pop_back();
+        data_temps[op.data_dest_index].divide(*ld, *rd);
+        data_temps_stack.push_back(&data_temps[op.data_dest_index]);
+        break;
+
       case ExprOpcode::MUL:
         rd = data_temps_stack.back(); data_temps_stack.pop_back();
         ld = data_temps_stack.back(); data_temps_stack.pop_back();
@@ -479,6 +495,7 @@ Expression::assign_dest_registers() {
       case ExprOpcode::ADD:
       case ExprOpcode::SUB:
       case ExprOpcode::MOD:
+      case ExprOpcode::DIV:
       case ExprOpcode::MUL:
       case ExprOpcode::SHIFT_LEFT:
       case ExprOpcode::SHIFT_RIGHT:

diff --git a/tests/test_conditionals.cpp b/tests/test_conditionals.cpp
@@ -191,6 +191,28 @@ TEST_F(ConditionalsTest, Add) {
   ASSERT_FALSE(c.eval(*phv));
 }
 
+TEST_F(ConditionalsTest, Divide) {
+  Conditional c("ctest", 0);
+
+  // we check that (2 == 7 / 3) && (1 == 7 % 3) evaluates to true
+  c.push_back_load_const(Data(2));
+  c.push_back_load_const(Data(7));
+  c.push_back_load_const(Data(3));
+  c.push_back_op(ExprOpcode::DIV);
+  c.push_back_op(ExprOpcode::EQ_DATA);
+
+  c.push_back_load_const(Data(1));
+  c.push_back_load_const(Data(7));
+  c.push_back_load_const(Data(3));
+  c.push_back_op(ExprOpcode::MOD);
+  c.push_back_op(ExprOpcode::EQ_DATA);
+
+  c.push_back_op(ExprOpcode::AND);
+
+  c.build();
+  ASSERT_TRUE(c.eval(*phv));
+}
+
 TEST_F(ConditionalsTest, And) {
   Conditional c1("c1test", 0);
   c1.push_back_load_bool(true);

diff --git a/tests/test_data.cpp b/tests/test_data.cpp
@@ -114,6 +114,28 @@ TEST(Data, ShiftRight) {
 
 namespace {
 
+// negative operands are not supported
+void test_divide(int a, int b) {
+  int q_exp = a / b;
+  int r_exp = a % b;
+  Data q, r;
+  q.divide(Data(a), Data(b));
+  r.mod(Data(a), Data(b));
+  ASSERT_EQ(q_exp, q.get_int());
+  ASSERT_EQ(r_exp, r.get_int());
+}
+
+}  // namespace
+
+TEST(Data, Divide) {
+  test_divide(7, 3);
+  test_divide(56343, 45);
+  test_divide(5, 5);
+  test_divide(0, 3);
+}
+
+namespace {
+
 void test_two_comp_mod(int src, unsigned int width, int expected) {
   Data dst;
   dst.two_comp_mod(Data(src), Data(width));