[aandrejevic] 60584: [SOFT386] Fix a bug in the CMP instruction. Implement the SBB instruction.
8 Oct
2013
8 Oct
'13
10:27 p.m.
Author: aandrejevic
Date: Tue Oct 8 22:27:48 2013
New Revision: 60584
URL: http://svn.reactos.org/svn/reactos?rev=60584&view=rev
Log:
[SOFT386]
Fix a bug in the CMP instruction.
Implement the SBB instruction.
Modified:
branches/ntvdm/lib/soft386/opcodes.c
Modified: branches/ntvdm/lib/soft386/opcodes.c
URL:
http://svn.reactos.org/svn/reactos/branches/ntvdm/lib/soft386/opcodes.c?rev…
==============================================================================
--- branches/ntvdm/lib/soft386/opcodes.c [iso-8859-1] (original)
+++ branches/ntvdm/lib/soft386/opcodes.c [iso-8859-1] Tue Oct 8 22:27:48 2013
@@ -3085,34 +3085,294 @@
SOFT386_OPCODE_HANDLER(Soft386OpcodeSbbByteModrm)
{
- // TODO: NOT IMPLEMENTED
- UNIMPLEMENTED;
-
- return FALSE;
+ UCHAR FirstValue, SecondValue, Result;
+ SOFT386_MOD_REG_RM ModRegRm;
+ BOOLEAN AddressSize = State->SegmentRegs[SOFT386_REG_CS].Size;
+ INT Carry = State->Flags.Cf ? 1 : 0;
+
+ /* Make sure this is the right instruction */
+ ASSERT((Opcode & 0xFD) == 0x18);
+
+ if (State->PrefixFlags & SOFT386_PREFIX_ADSIZE)
+ {
+ /* The ADSIZE prefix toggles the size */
+ AddressSize = !AddressSize;
+ }
+
+ /* Get the operands */
+ if (!Soft386ParseModRegRm(State, AddressSize, &ModRegRm))
+ {
+ /* Exception occurred */
+ return FALSE;
+ }
+
+ if (!Soft386ReadModrmByteOperands(State,
+ &ModRegRm,
+ &FirstValue,
+ &SecondValue))
+ {
+ /* Exception occurred */
+ return FALSE;
+ }
+
+ /* Check if this is the instruction that writes to R/M */
+ if (!(Opcode & SOFT386_OPCODE_WRITE_REG))
+ {
+ /* Swap the order */
+ FirstValue ^= SecondValue;
+ SecondValue ^= FirstValue;
+ FirstValue ^= SecondValue;
+ }
+
+ /* Calculate the result */
+ Result = FirstValue - SecondValue - Carry;
+
+ /* Update the flags */
+ State->Flags.Cf = FirstValue < (SecondValue + 1);
+ State->Flags.Of = ((FirstValue & SIGN_FLAG_BYTE) != (SecondValue &
SIGN_FLAG_BYTE))
+ && ((FirstValue & SIGN_FLAG_BYTE) != (Result &
SIGN_FLAG_BYTE));
+ State->Flags.Af = (FirstValue & 0x0F) < ((SecondValue + 1) & 0x0F);
+ State->Flags.Zf = (Result == 0) ? TRUE : FALSE;
+ State->Flags.Sf = (Result & SIGN_FLAG_BYTE) ? TRUE : FALSE;
+ State->Flags.Pf = Soft386CalculateParity(Result);
+
+ /* Write back the result */
+ return Soft386WriteModrmByteOperands(State,
+ &ModRegRm,
+ Opcode & SOFT386_OPCODE_WRITE_REG,
+ Result);
}
SOFT386_OPCODE_HANDLER(Soft386OpcodeSbbModrm)
{
- // TODO: NOT IMPLEMENTED
- UNIMPLEMENTED;
-
- return FALSE;
+ SOFT386_MOD_REG_RM ModRegRm;
+ BOOLEAN OperandSize, AddressSize;
+ INT Carry = State->Flags.Cf ? 1 : 0;
+
+ /* Make sure this is the right instruction */
+ ASSERT((Opcode & 0xFD) == 0x19);
+
+ OperandSize = AddressSize = State->SegmentRegs[SOFT386_REG_CS].Size;
+
+ if (State->PrefixFlags & SOFT386_PREFIX_ADSIZE)
+ {
+ /* The ADSIZE prefix toggles the address size */
+ AddressSize = !AddressSize;
+ }
+
+ if (State->PrefixFlags & SOFT386_PREFIX_OPSIZE)
+ {
+ /* The OPSIZE prefix toggles the operand size */
+ OperandSize = !OperandSize;
+ }
+
+ /* Get the operands */
+ if (!Soft386ParseModRegRm(State, AddressSize, &ModRegRm))
+ {
+ /* Exception occurred */
+ return FALSE;
+ }
+
+ /* Check the operand size */
+ if (OperandSize)
+ {
+ ULONG FirstValue, SecondValue, Result;
+
+ if (!Soft386ReadModrmDwordOperands(State,
+ &ModRegRm,
+ &FirstValue,
+ &SecondValue))
+ {
+ /* Exception occurred */
+ return FALSE;
+ }
+
+ /* Check if this is the instruction that writes to R/M */
+ if (!(Opcode & SOFT386_OPCODE_WRITE_REG))
+ {
+ /* Swap the order */
+ FirstValue ^= SecondValue;
+ SecondValue ^= FirstValue;
+ FirstValue ^= SecondValue;
+ }
+
+ /* Calculate the result */
+ Result = FirstValue - SecondValue - Carry;
+
+ /* Update the flags */
+ State->Flags.Cf = FirstValue < (SecondValue + Carry);
+ State->Flags.Of = ((FirstValue & SIGN_FLAG_LONG) != (SecondValue &
SIGN_FLAG_LONG))
+ && ((FirstValue & SIGN_FLAG_LONG) != (Result &
SIGN_FLAG_LONG));
+ State->Flags.Af = (FirstValue & 0x0F) < ((SecondValue + 1) &
0x0F);
+ State->Flags.Zf = (Result == 0) ? TRUE : FALSE;
+ State->Flags.Sf = (Result & SIGN_FLAG_LONG) ? TRUE : FALSE;
+ State->Flags.Pf = Soft386CalculateParity(Result);
+
+ /* Write back the result */
+ return Soft386WriteModrmDwordOperands(State,
+ &ModRegRm,
+ Opcode & SOFT386_OPCODE_WRITE_REG,
+ Result);
+ }
+ else
+ {
+ USHORT FirstValue, SecondValue, Result;
+
+ if (!Soft386ReadModrmWordOperands(State,
+ &ModRegRm,
+ &FirstValue,
+ &SecondValue))
+ {
+ /* Exception occurred */
+ return FALSE;
+ }
+
+ /* Check if this is the instruction that writes to R/M */
+ if (!(Opcode & SOFT386_OPCODE_WRITE_REG))
+ {
+ /* Swap the order */
+ FirstValue ^= SecondValue;
+ SecondValue ^= FirstValue;
+ FirstValue ^= SecondValue;
+ }
+
+ /* Calculate the result */
+ Result = FirstValue - SecondValue - Carry;
+
+ /* Update the flags */
+ State->Flags.Cf = FirstValue < (SecondValue + Carry);
+ State->Flags.Of = ((FirstValue & SIGN_FLAG_WORD) != (SecondValue &
SIGN_FLAG_WORD))
+ && ((FirstValue & SIGN_FLAG_WORD) != (Result &
SIGN_FLAG_WORD));
+ State->Flags.Af = (FirstValue & 0x0F) < ((SecondValue + 1) &
0x0F);
+ State->Flags.Zf = (Result == 0) ? TRUE : FALSE;
+ State->Flags.Sf = (Result & SIGN_FLAG_WORD) ? TRUE : FALSE;
+ State->Flags.Pf = Soft386CalculateParity(Result);
+
+ /* Write back the result */
+ return Soft386WriteModrmWordOperands(State,
+ &ModRegRm,
+ Opcode & SOFT386_OPCODE_WRITE_REG,
+ Result);
+ }
}
SOFT386_OPCODE_HANDLER(Soft386OpcodeSbbAl)
{
- // TODO: NOT IMPLEMENTED
- UNIMPLEMENTED;
-
- return FALSE;
+ UCHAR FirstValue = State->GeneralRegs[SOFT386_REG_EAX].LowByte;
+ UCHAR SecondValue, Result;
+ INT Carry = State->Flags.Cf ? 1 : 0;
+
+ /* Make sure this is the right instruction */
+ ASSERT(Opcode == 0x1C);
+
+ if (State->PrefixFlags)
+ {
+ /* This opcode doesn't take any prefixes */
+ Soft386Exception(State, SOFT386_EXCEPTION_UD);
+ return FALSE;
+ }
+
+ if (!Soft386FetchByte(State, &SecondValue))
+ {
+ /* Exception occurred */
+ return FALSE;
+ }
+
+ /* Calculate the result */
+ Result = FirstValue - SecondValue - Carry;
+
+ /* Update the flags */
+ State->Flags.Cf = FirstValue < (SecondValue + Carry);
+ State->Flags.Of = ((FirstValue & SIGN_FLAG_BYTE) != (SecondValue &
SIGN_FLAG_BYTE))
+ && ((FirstValue & SIGN_FLAG_BYTE) != (Result &
SIGN_FLAG_BYTE));
+ State->Flags.Af = (FirstValue & 0x0F) < ((SecondValue + 1) & 0x0F);
+ State->Flags.Zf = (Result == 0) ? TRUE : FALSE;
+ State->Flags.Sf = (Result & SIGN_FLAG_BYTE) ? TRUE : FALSE;
+ State->Flags.Pf = Soft386CalculateParity(Result);
+
+ /* Write back the result */
+ State->GeneralRegs[SOFT386_REG_EAX].LowByte = Result;
+
+ return TRUE;
+
}
SOFT386_OPCODE_HANDLER(Soft386OpcodeSbbEax)
{
- // TODO: NOT IMPLEMENTED
- UNIMPLEMENTED;
-
- return FALSE;
+ BOOLEAN Size = State->SegmentRegs[SOFT386_REG_CS].Size;
+ INT Carry = State->Flags.Cf ? 1 : 0;
+
+ /* Make sure this is the right instruction */
+ ASSERT(Opcode == 0x1D);
+
+ 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)
+ {
+ ULONG FirstValue = State->GeneralRegs[SOFT386_REG_EAX].Long;
+ ULONG SecondValue, Result;
+
+ if (!Soft386FetchDword(State, &SecondValue))
+ {
+ /* Exception occurred */
+ return FALSE;
+ }
+
+ /* Calculate the result */
+ Result = FirstValue - SecondValue - Carry;
+
+ /* Update the flags */
+ State->Flags.Cf = FirstValue < (SecondValue + Carry);
+ State->Flags.Of = ((FirstValue & SIGN_FLAG_LONG) != (SecondValue &
SIGN_FLAG_LONG))
+ && ((FirstValue & SIGN_FLAG_LONG) != (Result &
SIGN_FLAG_LONG));
+ State->Flags.Af = (FirstValue & 0x0F) < ((SecondValue + Carry) &
0x0F);
+ State->Flags.Zf = (Result == 0) ? TRUE : FALSE;
+ State->Flags.Sf = (Result & SIGN_FLAG_LONG) ? TRUE : FALSE;
+ State->Flags.Pf = Soft386CalculateParity(Result);
+
+ /* Write back the result */
+ State->GeneralRegs[SOFT386_REG_EAX].Long = Result;
+ }
+ else
+ {
+ USHORT FirstValue = State->GeneralRegs[SOFT386_REG_EAX].LowWord;
+ USHORT SecondValue, Result;
+
+ if (!Soft386FetchWord(State, &SecondValue))
+ {
+ /* Exception occurred */
+ return FALSE;
+ }
+
+ /* Calculate the result */
+ Result = FirstValue - SecondValue - Carry;
+
+ /* Update the flags */
+ State->Flags.Cf = FirstValue < (SecondValue + Carry);
+ State->Flags.Of = ((FirstValue & SIGN_FLAG_WORD) != (SecondValue &
SIGN_FLAG_WORD))
+ && ((FirstValue & SIGN_FLAG_WORD) != (Result &
SIGN_FLAG_WORD));
+ State->Flags.Af = (FirstValue & 0x0F) < ((SecondValue + Carry) &
0x0F);
+ State->Flags.Zf = (Result == 0) ? TRUE : FALSE;
+ State->Flags.Sf = (Result & SIGN_FLAG_WORD) ? TRUE : FALSE;
+ State->Flags.Pf = Soft386CalculateParity(Result);
+
+ /* Write back the result */
+ State->GeneralRegs[SOFT386_REG_EAX].LowWord = Result;
+ }
+
+ return TRUE;
+
}
SOFT386_OPCODE_HANDLER(Soft386OpcodePushDs)
@@ -3387,7 +3647,6 @@
return TRUE;
}
}
-
}
SOFT386_OPCODE_HANDLER(Soft386OpcodeCmpSubAl)
@@ -3506,8 +3765,12 @@
State->Flags.Sf = (Result & SIGN_FLAG_WORD) ? TRUE : FALSE;
State->Flags.Pf = Soft386CalculateParity(Result);
- /* Write back the result */
- State->GeneralRegs[SOFT386_REG_EAX].LowWord = Result;
+ /* Check if this is not a CMP */
+ if (!(Opcode & 0x10))
+ {
+ /* Write back the result */
+ State->GeneralRegs[SOFT386_REG_EAX].LowWord = Result;
+ }
}
return TRUE;
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