windows-nt/Source/XPSP1/NT/base/hals/x86new/setops.c
2020-09-26 16:20:57 +08:00

134 lines
2 KiB
C
Raw Blame History

This file contains invisible Unicode characters

This file contains invisible Unicode characters that are indistinguishable to humans but may be processed differently by a computer. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

/*++
Copyright (c) 1994 Microsoft Corporation
Module Name:
setops.c
Abstract:
This module implements the code to emulate set opcodes.
Author:
David N. Cutler (davec) 13-Sep-1994
Environment:
Kernel mode only.
Revision History:
--*/
#include "nthal.h"
#include "emulate.h"
VOID
XmSxxOp (
IN PRXM_CONTEXT P
)
/*++
Routine Description:
This function emulates set byte on condition opcodes.
Arguments:
P - Supplies a pointer to the emulation context structure.
Return Value:
None.
--*/
{
ULONG Complement;
ULONG Condition;
//
// Case on the set control value.
//
Complement = P->SrcValue.Long & 1;
switch (P->SrcValue.Long >> 1) {
//
// Set if overflow/not overflow.
//
case 0:
Condition = P->Eflags.EFLAG_OF;
break;
//
// Set if below/not below.
//
case 1:
Condition = P->Eflags.EFLAG_CF;
break;
//
// Set if zero/not zero.
//
case 2:
Condition = P->Eflags.EFLAG_ZF;
break;
//
// Set if below or equal/not below or equal.
//
case 3:
Condition = P->Eflags.EFLAG_CF | P->Eflags.EFLAG_ZF;
break;
//
// Set if signed/not signed.
//
case 4:
Condition = P->Eflags.EFLAG_SF;
break;
//
// Set if parity/not parity.
//
case 5:
Condition = P->Eflags.EFLAG_PF;
break;
//
// Set if less/not less.
//
case 6:
Condition = (P->Eflags.EFLAG_SF ^ P->Eflags.EFLAG_OF);
break;
//
// Set if less or equal/not less or equal.
//
case 7:
Condition = (P->Eflags.EFLAG_SF ^ P->Eflags.EFLAG_OF) | P->Eflags.EFLAG_ZF;
break;
}
//
// If the specified condition is met, then set the byte destination
// value to one. Otherwise, set the byte destination value to zero.
//
XmStoreResult(P, (ULONG)(Condition ^ Complement));
return;
}