All of the FPU opcodes fetch another byte which is the function number.
This is done by the CPU and it occurs even if there is no FPU attached.
svn path=/branches/ntvdm/; revision=62344
- Fix return values of Fast486OpcodeSahf and Fast486OpcodeLahf handlers.
- [TheFlash], can you please see what we should return after calling Fast486ExceptionWithErrorCode in Fast486OpcodePopFlags ?
svn path=/branches/ntvdm/; revision=62313
- When pushing 16-bit value, check only low word of ESP (i.e. SP).
- Don't forget to clear high word of EIP, for the Jump instruction of group 4 (0xFF).
svn path=/branches/ntvdm/; revision=62258
The current "fast" method used in MOVS gives incorrect results. It has been temporarily
replaced with a slow method that works correctly.
The string functions do nothing when CX is 0 on entry, fix CMPS and SCAS.
svn path=/branches/ntvdm/; revision=61203
Revert r61158, and fix the prefix issue correctly, but resetting the flags
again after the call to Fast486InterruptInternal.
svn path=/branches/ntvdm/; revision=61160
Move the prefix reset below the interrupt check, because Fast486InterruptInternal
might set OPSIZE in some circumstances.
svn path=/branches/ntvdm/; revision=61158
FPU instructions never generate #UD. If CR0.EM is set, they generate #NM.
If there is no FPU and CR0.EM is cleared, they do nothing.
Add a helper macro FPU_ST for accessing FPU registers.
Add a compile-time option to disable the FPU.
svn path=/branches/ntvdm/; revision=61150
Handle the case when the last page is also the first page in Fast486ReadLinearMemory ( when paging is enabled).
svn path=/branches/ntvdm/; revision=61104
The 486 doesn't have AC, VIF, VIP or ID.
Fix and simplify POPF.
[NTVDM]
Fix the count in the XMS copy function (INT 15h, AH = 87h).
svn path=/branches/ntvdm/; revision=61082
DAA, DAS: Update the flags.
AAA, AAS: Subtract from AX instead of AL. The specification says AL, but
so far in all known CPUs and emulators, AX is subtracted.
AAD: Clear AH.
svn path=/branches/ntvdm/; revision=61069
Make the parameters to Fast486ReadModrm*Operands optional, so that
unnecessary extra reads aren't performed. This also eliminates the
need for dummy variables.
svn path=/branches/ntvdm/; revision=61055
- When accessing memory using ESP, make the SS segment default.
- The INT instructions always pushes 16-bit values in real mode, regardless
of the operand/address size attributes.
svn path=/branches/ntvdm/; revision=61000
- Fix the privilege checks.
- Store the CPL in a special field, so that it doesn't get mixed up
with the lowest 2 bits of real mode selectors while switching
into protected mode.
- Reset the exception count after a successful ISR call.
- In Fast486OpcodeGroup0F01, check for prefix overrides after parsing
the Mod-Reg-R/M, which might add a SS: prefix override in some cases.
svn path=/branches/ntvdm/; revision=60995
