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[SOFT386]

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Halfplement REPZ/REPNZ for CMPS and SCAS.


svn path=/branches/ntvdm/; revision=60658
This commit is contained in:
Aleksandar Andrejevic 2013-10-13 23:59:52 +00:00
parent 4ad8a401ef
commit 642b52c4e1
1 changed files with 75 additions and 9 deletions
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84
lib/soft386/opcodes.c
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@ -6200,6 +6200,43 @@ SOFT386_OPCODE_HANDLER(Soft386OpcodeCmps)
}
}
// FIXME: This method is slow!
if ((State->PrefixFlags & SOFT386_PREFIX_REP)
|| (State->PrefixFlags & SOFT386_PREFIX_REPNZ))
{
BOOLEAN Repeat = TRUE;
if (OperandSize)
{
if ((--State->GeneralRegs[SOFT386_REG_ECX].Long) == 0)
{
/* ECX is 0 */
Repeat = FALSE;
}
}
else
{
if ((--State->GeneralRegs[SOFT386_REG_ECX].LowWord) == 0)
{
/* CX is 0 */
Repeat = FALSE;
}
}
if (((State->PrefixFlags & SOFT386_PREFIX_REP) && !State->Flags.Zf)
|| ((State->PrefixFlags & SOFT386_PREFIX_REPNZ) && State->Flags.Zf))
{
/* REPZ with ZF = 0 or REPNZ with ZF = 1 */
Repeat = FALSE;
}
if (Repeat)
{
/* Repeat the instruction */
State->InstPtr = State->SavedInstPtr;
}
}
/* Return success */
return TRUE;
}
@ -6444,16 +6481,8 @@ SOFT386_OPCODE_HANDLER(Soft386OpcodeScas)
AddressSize = !AddressSize;
}
if ((State->PrefixFlags & SOFT386_PREFIX_REP)
|| (State->PrefixFlags & SOFT386_PREFIX_REPNZ))
{
// TODO: The REP/REPZ/REPNZ prefixes need to be implemented!
Soft386Exception(State, SOFT386_EXCEPTION_UD);
return FALSE;
}
/* Calculate the size */
if (Opcode == 0xA6) DataSize = sizeof(UCHAR);
if (Opcode == 0xAE) DataSize = sizeof(UCHAR);
else DataSize = OperandSize ? sizeof(ULONG) : sizeof(USHORT);
/* Calculate the mask and sign flag */
@ -6499,6 +6528,43 @@ SOFT386_OPCODE_HANDLER(Soft386OpcodeScas)
else State->GeneralRegs[SOFT386_REG_EDI].LowWord -= DataSize;
}
// FIXME: This method is slow!
if ((State->PrefixFlags & SOFT386_PREFIX_REP)
|| (State->PrefixFlags & SOFT386_PREFIX_REPNZ))
{
BOOLEAN Repeat = TRUE;
if (OperandSize)
{
if ((--State->GeneralRegs[SOFT386_REG_ECX].Long) == 0)
{
/* ECX is 0 */
Repeat = FALSE;
}
}
else
{
if ((--State->GeneralRegs[SOFT386_REG_ECX].LowWord) == 0)
{
/* CX is 0 */
Repeat = FALSE;
}
}
if (((State->PrefixFlags & SOFT386_PREFIX_REP) && !State->Flags.Zf)
|| ((State->PrefixFlags & SOFT386_PREFIX_REPNZ) && State->Flags.Zf))
{
/* REPZ with ZF = 0 or REPNZ with ZF = 1 */
Repeat = FALSE;
}
if (Repeat)
{
/* Repeat the instruction */
State->InstPtr = State->SavedInstPtr;
}
}
/* Return success */
return TRUE;
}