SOFT386_OPCODE_HANDLER(Soft386OpcodeGroupFE)
{
- UNIMPLEMENTED;
- return FALSE; // TODO: NOT IMPLEMENTED
+ UCHAR Dummy, Value;
+ SOFT386_MOD_REG_RM ModRegRm;
+ BOOLEAN AddressSize = State->SegmentRegs[SOFT386_REG_CS].Size;
+
+ if (State->PrefixFlags & SOFT386_PREFIX_ADSIZE)
+ {
+ /* The ADSIZE prefix toggles the size */
+ AddressSize = !AddressSize;
+ }
+
+ if (!Soft386ParseModRegRm(State, AddressSize, &ModRegRm))
+ {
+ /* Exception occurred */
+ return FALSE;
+ }
+
+ if (ModRegRm.Register > 1)
+ {
+ /* Invalid */
+ Soft386Exception(State, SOFT386_EXCEPTION_UD);
+ return FALSE;
+ }
+
+ /* Read the operands */
+ if (!Soft386ReadModrmByteOperands(State, &ModRegRm, &Dummy, &Value))
+ {
+ /* Exception occurred */
+ return FALSE;
+ }
+
+ if (ModRegRm.Register == 0)
+ {
+ /* Increment and update OF */
+ Value++;
+ State->Flags.Of = (Value == SIGN_FLAG_BYTE) ? TRUE : FALSE;
+ }
+ else
+ {
+ /* Decrement and update OF */
+ State->Flags.Of = (Value == SIGN_FLAG_BYTE) ? TRUE : FALSE;
+ Value--;
+ }
+
+ /* Update flags */
+ State->Flags.Sf = (Value & SIGN_FLAG_BYTE) ? TRUE : FALSE;
+ State->Flags.Zf = (Value == 0) ? TRUE : FALSE;
+ State->Flags.Af = ((Value & 0x0F) == 0) ? TRUE : FALSE;
+ State->Flags.Pf = Soft386CalculateParity(Value);
+
+ /* Write back the result */
+ return Soft386WriteModrmByteOperands(State,
+ &ModRegRm,
+ FALSE,
+ Value);
}
SOFT386_OPCODE_HANDLER(Soft386OpcodeGroupFF)