Source code of Windows XP (NT5)
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3.2 KiB

/*++
Copyright (c) 1994 Microsoft Corporation
Module Name:
condops.c
Abstract:
This module implements the code to emulate condition code opcodes.
Author:
David N. Cutler (davec) 22-Sep-1994
Environment:
Kernel mode only.
Revision History:
--*/
#include "nthal.h"
#include "emulate.h"
VOID
XmClcOp (
PRXM_CONTEXT P
)
/*++
Routine Description:
This function emulates a clc opcode.
Arguments:
P - Supplies a pointer to an emulator context structure.
Return Value:
None.
--*/
{
//
// Clear carry flag.
//
P->Eflags.EFLAG_CF = 0;
return;
}
VOID
XmCldOp (
PRXM_CONTEXT P
)
/*++
Routine Description:
This function emulates a cld opcode.
Arguments:
P - Supplies a pointer to an emulator context structure.
Return Value:
None.
--*/
{
//
// Clear direction flag.
//
P->Eflags.EFLAG_DF = 0;
return;
}
VOID
XmCliOp (
PRXM_CONTEXT P
)
/*++
Routine Description:
This function emulates a cli opcode.
Arguments:
P - Supplies a pointer to an emulator context structure.
Return Value:
None.
--*/
{
//
// Clear interrupt flag.
//
P->Eflags.EFLAG_IF = 0;
return;
}
VOID
XmCmcOp (
PRXM_CONTEXT P
)
/*++
Routine Description:
This function emulates a cmc opcode.
Arguments:
P - Supplies a pointer to an emulator context structure.
Return Value:
None.
--*/
{
//
// Complement carry flag.
//
P->Eflags.EFLAG_CF ^= 1;
return;
}
VOID
XmStcOp (
PRXM_CONTEXT P
)
/*++
Routine Description:
This function emulates a stc opcode.
Arguments:
P - Supplies a pointer to an emulator context structure.
Return Value:
None.
--*/
{
//
// Set carry flag.
//
P->Eflags.EFLAG_CF = 1;
return;
}
VOID
XmStdOp (
PRXM_CONTEXT P
)
/*++
Routine Description:
This function emulates a std opcode.
Arguments:
P - Supplies a pointer to an emulator context structure.
Return Value:
None.
--*/
{
//
// Set direction flag.
//
P->Eflags.EFLAG_DF = 1;
return;
}
VOID
XmStiOp (
PRXM_CONTEXT P
)
/*++
Routine Description:
This function emulates a sti opcode.
Arguments:
P - Supplies a pointer to an emulator context structure.
Return Value:
None.
--*/
{
//
// Set interrupt flag.
//
P->Eflags.EFLAG_IF = 1;
return;
}
VOID
XmLahfOp (
PRXM_CONTEXT P
)
/*++
Routine Description:
This function emulates a lahf opcode.
Arguments:
P - Supplies a pointer to an emulator context structure.
Return Value:
None.
--*/
{
//
// Load flags into AH.
//
P->DataType = BYTE_DATA;
P->DstByte = &P->Gpr[AX].Xh;
XmStoreResult(P, (ULONG)P->AhFlags);
return;
}
VOID
XmSahfOp (
PRXM_CONTEXT P
)
/*++
Routine Description:
This function emulates a sahf opcode.
Arguments:
P - Supplies a pointer to an emulator context structure.
Return Value:
None.
--*/
{
//
// Store CF, PF, AF, ZF, SF of AH in flags.
//
P->AhFlags = P->Gpr[AX].Xh;
P->Eflags.EFLAG_MBO = 1;
P->Eflags.EFLAG_SBZ0 = 0;
P->Eflags.EFLAG_SBZ1 = 0;
return;
}