diff --git a/c/execute.c b/c/execute.c
index 2b8e65b..2ce404d 100644
--- a/c/execute.c
+++ b/c/execute.c
@@ -149,132 +149,225 @@ void op_checkcast(struct vm * vm, uint32_t index)
 
 void op_d2f(struct vm * vm)
 {
-  assert(!"op_d2f");
+  double value = operand_stack_pop_f64(vm->current_frame);
+  float result = (float)value;
+  operand_stack_push_f32(vm->current_frame, result);
 }
 
 void op_d2i(struct vm * vm)
 {
-  assert(!"op_d2i");
+  double value = operand_stack_pop_f64(vm->current_frame);
+  int32_t result = (int32_t)value;
+  operand_stack_push_u32(vm->current_frame, result);
 }
 
 void op_d2l(struct vm * vm)
 {
-  assert(!"op_d2l");
+  double value = operand_stack_pop_f64(vm->current_frame);
+  int64_t result = (int64_t)value;
+  operand_stack_push_u64(vm->current_frame, result);
 }
 
 void op_dadd(struct vm * vm)
 {
-  assert(!"op_dadd");
+  double value2 = operand_stack_pop_f64(vm->current_frame);
+  double value1 = operand_stack_pop_f64(vm->current_frame);
+  double result = value1 + value2;
+  operand_stack_push_f64(vm->current_frame, result);
 }
 
 void op_daload(struct vm * vm)
 {
-  assert(!"op_daload");
+  int32_t index = operand_stack_pop_u32(vm->current_frame);
+  int32_t * arrayref = (int32_t *)operand_stack_pop_u32(vm->current_frame);
+  assert(arrayref[0] > 0 && index < arrayref[0]);
+  int64_t * longarray = (int64_t *)&arrayref[1];
+  int64_t value = longarray[index];
+  operand_stack_push_u64(vm->current_frame, value);
 }
 
 void op_dastore(struct vm * vm)
 {
-  assert(!"op_dastore");
+  int64_t value = operand_stack_pop_u64(vm->current_frame);
+  int32_t index = operand_stack_pop_u32(vm->current_frame);
+  int32_t * arrayref = (int32_t *)operand_stack_pop_u32(vm->current_frame);
+  assert(arrayref[0] > 0 && index < arrayref[0]);
+  int64_t * longarray = (int64_t *)&arrayref[1];
+  longarray[index] = value;
 }
 
 void op_dcmpg(struct vm * vm)
 {
-  assert(!"op_dcmpg");
+  double value2 = operand_stack_pop_f64(vm->current_frame);
+  double value1 = operand_stack_pop_f64(vm->current_frame);
+  bool greater = value1 > value2;
+  bool equal = value1 == value2;
+  int32_t value;
+  if (__builtin_isnan(value1) || __builtin_isnan(value2)) {
+    value = 1;
+  } else if (equal) {
+    value = 0;
+  } else if (greater) {
+    value = 1;
+  } else { // less than
+    value = -1;
+  }
+  operand_stack_push_u32(vm->current_frame, value);
 }
 
 void op_dcmpl(struct vm * vm)
 {
-  assert(!"op_dcmpl");
+  double value2 = operand_stack_pop_f64(vm->current_frame);
+  double value1 = operand_stack_pop_f64(vm->current_frame);
+  bool greater = value1 > value2;
+  bool equal = value1 == value2;
+  int32_t value;
+  if (__builtin_isnan(value1) || __builtin_isnan(value2)) {
+    value = -1;
+  } else if (equal) {
+    value = 0;
+  } else if (greater) {
+    value = 1;
+  } else { // less than
+    value = -1;
+  }
+  operand_stack_push_u32(vm->current_frame, value);
 }
 
 void op_dconst_0(struct vm * vm)
 {
-  assert(!"op_dconst_0");
+  operand_stack_push_f64(vm->current_frame, 0.0f);
 }
 
 void op_dconst_1(struct vm * vm)
 {
-  assert(!"op_dconst_1");
+  operand_stack_push_f64(vm->current_frame, 1.0f);
 }
 
 void op_ddiv(struct vm * vm)
 {
-  assert(!"op_ddiv");
+  double value2 = operand_stack_pop_f64(vm->current_frame);
+  double value1 = operand_stack_pop_f64(vm->current_frame);
+  double result = value1 / value2;
+  operand_stack_push_f64(vm->current_frame, result);
 }
 
 void op_dload(struct vm * vm, uint32_t index)
 {
-  assert(!"op_dload");
+  uint32_t low = vm->current_frame->local_variable[index];
+  uint32_t high = vm->current_frame->local_variable[index + 1];
+  operand_stack_push_u32(vm->current_frame, low);
+  operand_stack_push_u32(vm->current_frame, high);
 }
 
 void op_dload_0(struct vm * vm)
 {
-  assert(!"op_dload_0");
+  uint32_t low = vm->current_frame->local_variable[0];
+  uint32_t high = vm->current_frame->local_variable[0 + 1];
+  operand_stack_push_u32(vm->current_frame, low);
+  operand_stack_push_u32(vm->current_frame, high);
 }
 
 void op_dload_1(struct vm * vm)
 {
-  assert(!"op_dload_1");
+  uint32_t low = vm->current_frame->local_variable[1];
+  uint32_t high = vm->current_frame->local_variable[1 + 1];
+  operand_stack_push_u32(vm->current_frame, low);
+  operand_stack_push_u32(vm->current_frame, high);
 }
 
 void op_dload_2(struct vm * vm)
 {
-  assert(!"op_dload_2");
+  uint32_t low = vm->current_frame->local_variable[2];
+  uint32_t high = vm->current_frame->local_variable[2 + 1];
+  operand_stack_push_u32(vm->current_frame, low);
+  operand_stack_push_u32(vm->current_frame, high);
 }
 
 void op_dload_3(struct vm * vm)
 {
-  assert(!"op_dload_3");
+  uint32_t low = vm->current_frame->local_variable[3];
+  uint32_t high = vm->current_frame->local_variable[3 + 1];
+  operand_stack_push_u32(vm->current_frame, low);
+  operand_stack_push_u32(vm->current_frame, high);
 }
 
 void op_dmul(struct vm * vm)
 {
-  assert(!"op_dmul");
+  double value2 = operand_stack_pop_f64(vm->current_frame);
+  double value1 = operand_stack_pop_f64(vm->current_frame);
+  double result = value1 * value2;
+  operand_stack_push_f64(vm->current_frame, result);
 }
 
 void op_dneg(struct vm * vm)
 {
-  assert(!"op_dneg");
+  double value = operand_stack_pop_f64(vm->current_frame);
+  double result = -value;
+  operand_stack_push_f64(vm->current_frame, result);
 }
 
 void op_drem(struct vm * vm)
 {
-  assert(!"op_drem");
+  double value2 = operand_stack_pop_f64(vm->current_frame);
+  double value1 = operand_stack_pop_f64(vm->current_frame);
+  double q = value1 / value2;
+  double result = value1 - (value2 * (double)((int64_t)q));
+  operand_stack_push_f64(vm->current_frame, result);
 }
 
 void op_dreturn(struct vm * vm)
 {
-  assert(!"op_dreturn");
+  assert(vm->current_frame->return_type == 'D');
+  vm_method_return(vm);
 }
 
 void op_dstore(struct vm * vm, uint32_t index)
 {
-  assert(!"op_dstore");
+  uint32_t high = operand_stack_pop_u32(vm->current_frame);
+  uint32_t low = operand_stack_pop_u32(vm->current_frame);
+  vm->current_frame->local_variable[index + 1] = high;
+  vm->current_frame->local_variable[index] = low;
 }
 
 void op_dstore_0(struct vm * vm)
 {
-  assert(!"op_dstore_0");
+  uint32_t high = operand_stack_pop_u32(vm->current_frame);
+  uint32_t low = operand_stack_pop_u32(vm->current_frame);
+  vm->current_frame->local_variable[0 + 1] = high;
+  vm->current_frame->local_variable[0] = low;
 }
 
 void op_dstore_1(struct vm * vm)
 {
-  assert(!"op_dstore_1");
+  uint32_t high = operand_stack_pop_u32(vm->current_frame);
+  uint32_t low = operand_stack_pop_u32(vm->current_frame);
+  vm->current_frame->local_variable[1 + 1] = high;
+  vm->current_frame->local_variable[1] = low;
 }
 
 void op_dstore_2(struct vm * vm)
 {
-  assert(!"op_dstore_2");
+  uint32_t high = operand_stack_pop_u32(vm->current_frame);
+  uint32_t low = operand_stack_pop_u32(vm->current_frame);
+  vm->current_frame->local_variable[2 + 1] = high;
+  vm->current_frame->local_variable[2] = low;
 }
 
 void op_dstore_3(struct vm * vm)
 {
-  assert(!"op_dstore_3");
+  uint32_t high = operand_stack_pop_u32(vm->current_frame);
+  uint32_t low = operand_stack_pop_u32(vm->current_frame);
+  vm->current_frame->local_variable[3 + 1] = high;
+  vm->current_frame->local_variable[3] = low;
 }
 
 void op_dsub(struct vm * vm)
 {
-  assert(!"op_dsub");
+  double value2 = operand_stack_pop_f64(vm->current_frame);
+  double value1 = operand_stack_pop_f64(vm->current_frame);
+  double result = value1 - value2;
+  operand_stack_push_f64(vm->current_frame, result);
 }
 
 void op_dup(struct vm * vm)
@@ -309,7 +402,9 @@ void op_dup_x2(struct vm * vm)
 
 void op_f2d(struct vm * vm)
 {
-  assert(!"op_f2d");
+  float value = operand_stack_pop_f32(vm->current_frame);
+  double result = (double)value;
+  operand_stack_push_f64(vm->current_frame, result);
 }
 
 void op_f2i(struct vm * vm)
@@ -589,7 +684,9 @@ void op_i2c(struct vm * vm)
 
 void op_i2d(struct vm * vm)
 {
-  assert(!"op_i2d");
+  int32_t value = operand_stack_pop_u32(vm->current_frame);
+  double result = (double)value;
+  operand_stack_push_f64(vm->current_frame, result);
 }
 
 void op_i2f(struct vm * vm)
@@ -1092,7 +1189,9 @@ void op_jsr_w(struct vm * vm, int32_t branch)
 
 void op_l2d(struct vm * vm)
 {
-  assert(!"op_l2d");
+  int64_t value = operand_stack_pop_u64(vm->current_frame);
+  double result = (double)value;
+  operand_stack_push_f64(vm->current_frame, result);
 }
 
 void op_l2f(struct vm * vm)
diff --git a/c/frame.h b/c/frame.h
index 24040ea..88b0b0a 100644
--- a/c/frame.h
+++ b/c/frame.h
@@ -127,6 +127,26 @@ static inline uint64_t operand_stack_pop_u64(struct frame * frame)
   return value;
 }
 
+static inline void operand_stack_push_f64(struct frame * frame, double f)
+{
+  uint64_t value = *((uint64_t *)&f);
+  frame->operand_stack[frame->operand_stack_ix] = (uint32_t)(value >> 0);
+  frame->operand_stack_ix++;
+  frame->operand_stack[frame->operand_stack_ix] = (uint32_t)(value >> 32);
+  frame->operand_stack_ix++;
+}
+
+static inline double operand_stack_pop_f64(struct frame * frame)
+{
+  frame->operand_stack_ix--;
+  uint64_t high = frame->operand_stack[frame->operand_stack_ix];
+  frame->operand_stack_ix--;
+  uint64_t low = frame->operand_stack[frame->operand_stack_ix];
+  uint64_t value = (high << 32) | (low << 0);
+  double f = *((double *)&value);
+  return f;
+}
+
 bool vm_initialize_class(struct vm * vm, struct class_entry * class_entry);
 void vm_static_method_call(struct vm * vm, struct class_file * class_file, struct method_info * method_info);
 void vm_method_return(struct vm * vm);
diff --git a/p/Double.java b/p/Double.java
new file mode 100644
index 0000000..c5c5b7d
--- /dev/null
+++ b/p/Double.java
@@ -0,0 +1,48 @@
+package p;
+
+class Double {
+    public static void main() {
+        test();
+        test2();
+        test3(3.0);
+    }
+
+    static double test() {
+        double a = 1.0;
+        double b = a / 3.0;
+        double c = b * 2.0;
+        double d = c + 5.0;
+        double e = d - 0.5;
+        double f = -e;
+        double g = f % 2.0;
+        int h = (int)g;
+        return h;
+    }
+
+    static double test2() {
+        double[] arr = {1.0, 2.1, 3.2, 4.3};
+        double sum = 0;
+        for (int i = 0; i < arr.length; i++) {
+            sum += arr[i];
+        }
+        boolean b = sum < 1.0;
+        double i = 0.0;
+        if (b)
+            i = 1.0;
+        return i * 4.2;
+    }
+
+    static double test3(double n) {
+        float a = (float)n;
+        int b = (int)n;
+        long c = (long)n;
+        char d = (char)n;
+
+        double e = (double)a;
+        double f = (double)b;
+        double g = (double)c;
+        double h = (double)d;
+
+        return e * f * g * h;
+    }
+}