Function ExecuteCALL

MdeModulePkg/Universal/EbcDxe/EbcExecute.c:2966–3098

Implements the EBC CALL instruction. Instruction format: CALL64 Immed64 CALL32 {@}R1 {Immed32|Index32} CALLEX64 Immed64 CALLEX16 {@}R1 {Immed32} If Rx == R0, then it's a PC relative call to PC = PC + imm32. @param VmPtr A pointer to a VM context. @retval EFI_SUCCESS The instruction is executed successfully. **/

**/
EFI_STATUS
ExecuteCALL (
  IN VM_CONTEXT *VmPtr
  )
{
  UINT8 Opcode;
  UINT8 Operands;
  INT32 Immed32;
  UINT8 Size;
  INT64 Immed64;
  VOID  *FramePtr;

  //
  // Get opcode and operands
  //
  Opcode    = GETOPCODE (VmPtr);
  Operands  = GETOPERANDS (VmPtr);

  if ((Operands & OPERAND_M_NATIVE_CALL) != 0) {
    EbcDebuggerHookCALLEXStart (VmPtr);
  } else {
    EbcDebuggerHookCALLStart (VmPtr);
  }

  //
  // Assign these as well to avoid compiler warnings
  //
  Immed64   = 0;
  Immed32   = 0;

  FramePtr  = VmPtr->FramePtr;
  //
  // Determine the instruction size, and get immediate data if present
  //
  if ((Opcode & OPCODE_M_IMMDATA) != 0) {
    if ((Opcode & OPCODE_M_IMMDATA64) != 0) {
      Immed64 = VmReadImmed64 (VmPtr, 2);
      Size    = 10;
    } else {
      //
      // If register operand is indirect, then the immediate data is an index
      //
      if (OPERAND1_INDIRECT (Operands)) {
        Immed32 = VmReadIndex32 (VmPtr, 2);
      } else {
        Immed32 = VmReadImmed32 (VmPtr, 2);
      }

      Size = 6;
    }
  } else {
    Size = 2;
  }
  //
  // If it's a call to EBC, adjust the stack pointer down 16 bytes and
  // put our return address and frame pointer on the VM stack.
  //
  if ((Operands & OPERAND_M_NATIVE_CALL) == 0) {