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[SOFT386]

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Implement JECXZ, LOOP, LOOPZ and LOOPNZ.


svn path=/branches/ntvdm/; revision=60226
This commit is contained in:
Aleksandar Andrejevic 2013-09-19 22:48:45 +00:00
parent 3dc329ae81
commit d3a6556ea5
2 changed files with 86 additions and 26 deletions
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106
lib/soft386/opcodes.c
View file

@ -248,8 +248,8 @@ Soft386OpcodeHandlers[SOFT386_NUM_OPCODE_HANDLERS] =
NULL, // TODO: OPCODE 0xDD NOT SUPPORTED
NULL, // TODO: OPCODE 0xDE NOT SUPPORTED
NULL, // TODO: OPCODE 0xDF NOT SUPPORTED
Soft386OpcodeLoopnz,
Soft386OpcodeLoopz,
Soft386OpcodeLoop,
Soft386OpcodeLoop,
Soft386OpcodeLoop,
Soft386OpcodeJecxz,
Soft386OpcodeInByte,
@ -4323,36 +4323,98 @@ SOFT386_OPCODE_HANDLER(Soft386OpcodeXlat)
return FALSE;
}
SOFT386_OPCODE_HANDLER(Soft386OpcodeLoopnz)
{
// TODO: NOT IMPLEMENTED
UNIMPLEMENTED;
return FALSE;
}
SOFT386_OPCODE_HANDLER(Soft386OpcodeLoopz)
{
// TODO: NOT IMPLEMENTED
UNIMPLEMENTED;
return FALSE;
}
SOFT386_OPCODE_HANDLER(Soft386OpcodeLoop)
{
// TODO: NOT IMPLEMENTED
UNIMPLEMENTED;
BOOLEAN Condition;
BOOLEAN Size = State->SegmentRegs[SOFT386_REG_CS].Size;
CHAR Offset = 0;
/* Make sure this is the right instruction */
ASSERT((Opcode >= 0xE0) && (Opcode <= 0xE2));
if (State->PrefixFlags & SOFT386_PREFIX_LOCK)
{
/* Invalid prefix */
Soft386Exception(State, SOFT386_EXCEPTION_UD);
return FALSE;
}
if (State->PrefixFlags == SOFT386_PREFIX_OPSIZE)
{
/* The OPSIZE prefix toggles the size */
Size = !Size;
}
if (Size) Condition = ((--State->GeneralRegs[SOFT386_REG_ECX].Long) == 0);
else Condition = ((--State->GeneralRegs[SOFT386_REG_ECX].LowWord) == 0);
if (Opcode == 0xE0)
{
/* Additional rule for LOOPNZ */
if (State->Flags.Zf) Condition = FALSE;
}
if (Opcode == 0xE1)
{
/* Additional rule for LOOPZ */
if (!State->Flags.Zf) Condition = FALSE;
}
/* Fetch the offset */
if (!Soft386FetchByte(State, (PUCHAR)&Offset))
{
/* An exception occurred */
return FALSE;
}
if (Condition)
{
/* Move the instruction pointer */
State->InstPtr.Long += Offset;
}
return TRUE;
}
SOFT386_OPCODE_HANDLER(Soft386OpcodeJecxz)
{
// TODO: NOT IMPLEMENTED
UNIMPLEMENTED;
BOOLEAN Condition;
BOOLEAN Size = State->SegmentRegs[SOFT386_REG_CS].Size;
CHAR Offset = 0;
/* Make sure this is the right instruction */
ASSERT(Opcode == 0xE3);
if (State->PrefixFlags & SOFT386_PREFIX_LOCK)
{
/* Invalid prefix */
Soft386Exception(State, SOFT386_EXCEPTION_UD);
return FALSE;
}
if (State->PrefixFlags == SOFT386_PREFIX_OPSIZE)
{
/* The OPSIZE prefix toggles the size */
Size = !Size;
}
if (Size) Condition = (State->GeneralRegs[SOFT386_REG_ECX].Long == 0);
else Condition = (State->GeneralRegs[SOFT386_REG_ECX].LowWord == 0);
/* Fetch the offset */
if (!Soft386FetchByte(State, (PUCHAR)&Offset))
{
/* An exception occurred */
return FALSE;
}
if (Condition)
{
/* Move the instruction pointer */
State->InstPtr.Long += Offset;
}
return TRUE;
}
SOFT386_OPCODE_HANDLER(Soft386OpcodeCall)

2
lib/soft386/opcodes.h
View file

@ -130,8 +130,6 @@ SOFT386_OPCODE_HANDLER(Soft386OpcodeIret);
SOFT386_OPCODE_HANDLER(Soft386OpcodeAam);
SOFT386_OPCODE_HANDLER(Soft386OpcodeAad);
SOFT386_OPCODE_HANDLER(Soft386OpcodeXlat);
SOFT386_OPCODE_HANDLER(Soft386OpcodeLoopnz);
SOFT386_OPCODE_HANDLER(Soft386OpcodeLoopz);
SOFT386_OPCODE_HANDLER(Soft386OpcodeLoop);
SOFT386_OPCODE_HANDLER(Soft386OpcodeJecxz);
SOFT386_OPCODE_HANDLER(Soft386OpcodeCall);