1  /*
 2   *  Bean Java VM
 3   *  Copyright (C) 2005-2015 Christian Lins <christian@lins.me>
 4   *
 5   *  Licensed under the Apache License, Version 2.0 (the "License");
 6   *  you may not use this file except in compliance with the License.
 7   *  You may obtain a copy of the License at
 8   *
 9   *     http://www.apache.org/licenses/LICENSE-2.0
10   *
11   *  Unless required by applicable law or agreed to in writing, software
12   *  distributed under the License is distributed on an "AS IS" BASIS,
13   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   *  See the License for the specific language governing permissions and
15   *  limitations under the License.
16   */
17  
18  #include <debug.h>
19  #include <vm.h>
20  
21  /* Branch if reference is NULL */
22  void do_IFNULL(Thread *thread)
23  {
24      dbgmsg("IFNULL");
25  
26      Varframe *ref;
27      uint16_t offset;
28      Stackframe *frame = current_frame(thread);
29  
30      /* Pop reference from operand stack */
31      Stack_pop(&(frame->operandStack), (void **) &ref);
32  
33      /* Get branch offset */
34      offset = Get2ByteOperand(current_frame(thread));
35  
36      /* Check if we should branch (ref == NULL) */
37      if (ref->data.ptr == NULL) {
38          /* -1 because the IP points to the first operand byte */
39          current_frame(thread)->instPtr += offset - 1;   // Correct?
40      } else {
41          /* else do nothing (continue with execution) */
42          //thread->InstructionPointer++; // done in exec_thread
43      }
44  }