Function ExecutePUSH

MdeModulePkg/Universal/EbcDxe/EbcExecute.c:2747–2809

Execute the EBC PUSH instruction. Instruction syntax: PUSH[32|64] {@}R1 {Index16|Immed16} @param VmPtr A pointer to a VM context. @retval EFI_SUCCESS The instruction is executed successfully. **/

**/
EFI_STATUS
ExecutePUSH (
  IN VM_CONTEXT *VmPtr
  )
{
  UINT8   Opcode;
  UINT8   Operands;
  UINT32  Data32;
  UINT64  Data64;
  INT16   Index16;

  //
  // Get opcode and operands
  //
  Opcode    = GETOPCODE (VmPtr);
  Operands  = GETOPERANDS (VmPtr);
  //
  // Get immediate index if present, then advance the IP.
  //
  if ((Opcode & PUSHPOP_M_IMMDATA) != 0) {
    if (OPERAND1_INDIRECT (Operands)) {
      Index16 = VmReadIndex16 (VmPtr, 2);
    } else {
      Index16 = VmReadImmed16 (VmPtr, 2);
    }

    VmPtr->Ip += 4;
  } else {
    Index16 = 0;
    VmPtr->Ip += 2;
  }
  //
  // Get the data to push
  //
  if ((Opcode & PUSHPOP_M_64) != 0) {
    if (OPERAND1_INDIRECT (Operands)) {
      Data64 = VmReadMem64 (VmPtr, (UINTN) (VmPtr->Gpr[OPERAND1_REGNUM (Operands)] + Index16));
    } else {
      Data64 = (UINT64) VmPtr->Gpr[OPERAND1_REGNUM (Operands)] + Index16;
    }
    //
    // Adjust the stack down, then write back the data
    //
    VmPtr->Gpr[0] -= sizeof (UINT64);
    VmWriteMem64 (VmPtr, (UINTN) VmPtr->Gpr[0], Data64);
  } else {
    //
    // 32-bit data
    //
    if (OPERAND1_INDIRECT (Operands)) {
      Data32 = VmReadMem32 (VmPtr, (UINTN) (VmPtr->Gpr[OPERAND1_REGNUM (Operands)] + Index16));
    } else {
      Data32 = (UINT32) VmPtr->Gpr[OPERAND1_REGNUM (Operands)] + Index16;
    }
    //
    // Adjust the stack down and write the data
    //
    VmPtr->Gpr[0] -= sizeof (UINT32);