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page ,132 subttl emerror.asm - Emulator error handler;***;emerror.asm - Emulator error handler;; Microsoft Confidential;; Copyright (c) Microsoft Corporation 1987, 1991;; All Rights Reserved;;Purpose:; Emulator error handler;;Revision History: (also see emulator.hst);; 10/30/89 WAJ Added this header.; 11/15/89 WAJ Major changes for Dos32RaiseExcpetion().; 12/01/89 WAJ Now set cbExceptionInfo correctly.; 02/08/90 WAJ Fixed GP fault in 32 bit exception handler.; 09/03/91 JWM Modified entry/exit sequence for DOSX32.; 02/15/92 JWM Adapted for NT.;;*******************************************************************************
ifdef _DOS32EXTinclude except32.incendif
;*** error_return - return to user code (regardless of error);; This macro returns to user code. It goes to some lengths; to restore the flags on the instruction immediately before; the return so that any pending trace trap will be; acknowledged immediately after the retfd (and before the; next user instruction) instead of after the instruction; following the return as would be the case if we returned; using iretd.;; ENTRY ((SS:ESP)) = user's EAX; ((SS:ESP)+4) = return EIP; ((SS:ESP)+8) = return CS; ((SS:ESP)+12) = user's EFLAGS; EXIT return to user program, above arguments; popped off stack, user's EAX and EFLAGS; restored.
error_return macro noerrorifdef _DOS32EXT sti ; JWM, 9/3/91 push dword ptr [esp+8] ; JWM, 9/6/91 popfd ; JWM, 9/6/91endif ; DOS32EXT
ifdef NT386if DBG push dword ptr [esp+8] ; On checked build, allow popfd ; single step to workendifendif iretd endm
TESTif macro nam mov bl,err&nam ; default error number if (nam ge 100h) test ah,nam/256 else ;not (nam ge 100h) test al,nam endif ;(nam ge 100h) JSNZ signalerror endm
EM_ENTRY eCommonExceptionsCommonExceptions: mov ebx,[esp].[OldLongStatus] and ebx,LongSavedFlags ;preserve condition codes, error flags or EMSEG:[LongStatusWord],ebx ;merge saved status word, condition codes pop eax pop ecx pop edx pop ebx add esp,4 ; toss esp value pop ebp pop esi pop edi add esp,8 ;toss old PrevCodeOff and StatusWord pop ds call Emexcept error_return noerror
ifdef _DOS32EXT
EmExcept PROC C, OldEIP:DWORD, OldCS:DWORD, OldFlags:DWORD
LOCAL SSAR:DWORDLOCAL ec:_DX32_CONTEXT
;* ;* Set up SS access rights. ;*
push ds mov [ec.R_Eax], eax GetEmData ds,ax
mov eax, ss lar eax, eax mov [SSAR], eax
;* ;* Fill in ExceptionContext structure. ;*
mov [ec.NPXContextFlags], NPX_CONTEXT_FULL mov [ec.R_Edi], edi mov [ec.R_Esi], esi
mov eax, [ebp] mov [ec.R_Ebp], eax
lea eax, [OldFlags+4] mov [ec.R_Esp], eax
mov [ec.R_Ebx], ebx mov [ec.R_Edx], edx mov [ec.R_Ecx], ecx
mov eax, EMSEG:[PrevCodeOff]
mov [ec.R_Eip], eax mov eax, [OldFlags] mov [ec.EFlags], eax
mov eax, [OldCS] movzx eax,ax mov [ec.SegCs], eax mov ax,ss movzx eax,ax mov [ec.SegSs], eax
pop eax movzx eax,ax mov [ec.SegDs], eax ; ds was pushed on entry.
mov ax,es movzx eax,ax mov [ec.SegEs], eax
mov ax,fs movzx eax,ax mov [ec.SegFs], eax
mov ax,gs movzx eax,ax mov [ec.SegGs], eax
lea esi, [ec] add esi, 4
push ebp call SaveState pop ebp
lea eax, [ec] push ds push es
mov bx, seg FLAT:CURstk mov ds, ebx mov es, ebx push eax
call DOS32RAISEEXCEPTION
add esp, 4
pop es pop ds
RaiseExceptRet: or eax, eax JZ ExceptNotHandled
;* ;* Copy new flags, cs, eip to new stack. ;*
mov ds, [ec.SegSs] mov esi, [ec.R_Esp] ; ds:esi == new ss:esp
mov eax, [ec.Eflags] ; set up iretd frame mov [esi-4], eax
mov eax, [ec.SegCs] mov [esi-8], eax
mov eax, [ec.R_Eip] mov [esi-12], eax
;* ;* Put new stack pointer on stack. ;*
push ds sub esi, 12 push esi
;* ;* Reset other registers. ;*
mov edi, [ec.R_Edi] mov esi, [ec.R_Esi] mov ebx, [ec.R_Ebx] mov edx, [ec.R_Edx] mov ecx, [ec.R_Ecx] mov eax, [ec.R_Eax] mov ds, [ec.SegDs] mov es, [ec.SegEs] mov fs, [ec.SegFs] mov gs, [ec.SegGs]
mov ebp, [ec.R_Ebp] ; must do this last.
lss esp, fword ptr [esp] ; reset ss:esp
sti ; JWM, 9/3/91 push [esp+8] ; JWM, 9/6/91 popfd ; JWM, 9/6/91
iretd ; reset flags, cs, eip
ExceptNotHandled:EmExcept ENDP
endif ; ifdef _DOS32EXT
ifdef NT386
ISIZE equ 4ISizeEC equ (ContextFrameLength + ISIZE - 1) and (not (ISIZE - 1))ISizeExceptStruct equ (ExceptionRecordLength + ISIZE - 1) and (not (ISIZE - 1))
ec_off EQU 4+ISizeEcestruct_off EQU ec_off+ISizeExceptStruct
SSAR EQU <[ebp][-4]>ec EQU <[ebp][-ec_off]>eStruct EQU <[ebp][-estruct_off]>
OldEIP EQU <ebp+8>OldCS EQU <ebp+12>OldFlags EQU <ebp+16>
EmExcept PROC NEAR
push ebp mov ebp,esp sub esp,estruct_off
;* ;* Set up SS access rights. ;*
push ds mov [ec.ctx_RegEax], eax GetEmData ds,ax
mov eax, ss lar eax, eax mov [SSAR], eax
;* ;* Fill in ExceptionContext structure. ;*
mov dword ptr [ec.ContextFlags], NPX_CONTEXT_FULL mov dword ptr [ec.ctx_Cr0NpxState], CR0_EM mov [ec.ctx_RegEdi], edi mov [ec.ctx_RegEsi], esi
mov eax, [ebp] mov [ec.ctx_RegEbp], eax
lea eax, [OldFlags+4] mov [ec.ctx_RegEsp], eax
mov [ec.ctx_RegEbx], ebx mov [ec.ctx_RegEdx], edx mov [ec.ctx_RegEcx], ecx
mov eax, [OldEIP]
mov [ec.ctx_RegEip], eax mov eax, [OldFlags] mov [ec.ctx_EFlags], eax
mov eax, [OldCS] movzx eax,ax mov [ec.ctx_SegCs], eax mov ax,ss movzx eax,ax mov [ec.ctx_SegSs], eax
pop eax movzx eax,ax mov [ec.ctx_SegDs], eax ; ds was pushed on entry.
mov ax,es movzx eax,ax mov [ec.ctx_SegEs], eax
mov ax,fs movzx eax,ax mov [ec.ctx_SegFs], eax
mov ax,gs movzx eax,ax mov [ec.ctx_SegGs], eax
lea esi, [ec] add esi, ctx_env
or EMSEG:[StatusWord], 8000H ; set 'busy' bit or EMSEG:[SWerr], Summary ; set Summary bit or EMSEG:[CURerr], Summary
mov cl, EMSEG:[ErrMask] push ecx push ebp call SaveState pop ebp pop ecx
call GetEMSEGStatusWord ; EAX = status word test al, cl ; test status word against mask jne short Err00
ifdef TRACENPX mov edx, 0C1020304h ; Raise bogus exception code, to trace with jmp short Err50endif mov al, Invalid
;; According to the floating error priority, we test what is the cause of; the NPX error and raise an appropriate exception.;
Err00: test al, Invalid ; Invalid Op? jz short Err10 ; No, go check next
mov edx, XCPT_FLOAT_INVALID_OPERATION test al, StackFlag ; Stack fault? jz short Err50 ; No, go raise invalid op mov edx, XCPT_FLOAT_STACK_CHECK jmp short Err50 ; Go raise stack fault
Err10: mov edx, XCPT_FLOAT_DIVIDE_BY_ZERO test al, ZeroDivide jnz short Err50 mov edx, XCPT_FLOAT_DENORMAL_OPERAND test al, Denormal jnz short Err50 mov edx, XCPT_FLOAT_OVERFLOW test al, Overflow jnz short Err50 mov edx, XCPT_FLOAT_UNDERFLOW test al, Underflow jnz short Err50 mov edx, XCPT_FLOAT_INEXACT_RESULT
Err50: mov [eStruct.ExceptionNum], edx
xor eax,eax mov [eStruct.fHandlerFlags], eax mov [eStruct.NestedExceptionReportRecord], eax mov dword ptr [eStruct.CParameters], 1 ; GeorgioP convention mov [eStruct.ErExceptionInformation], eax ; GeorgioP convention
mov eax, EMSEG:[PrevCodeOff] mov [eStruct.ExceptionAddress], eax
lea edx, [eStruct]
lea eax, [ec] push ds push es
;TRUE, this is a first-chance exception
stdCall _NtRaiseException,<edx, eax, 1> stdCall _RtlRaiseStatus, <eax>
pop es pop ds
RaiseExceptRet: or eax, eax JZ ExceptNotHandled
;* ;* Copy new flags, cs, eip to new stack. ;*
mov ds, [ec.ctx_SegSs] mov esi, [ec.ctx_RegEsp] ; ds:esi == new ss:esp
mov eax, [ec.ctx_Eflags] ; set up iretd frame mov [esi-4], eax
mov eax, [ec.ctx_SegCs] mov [esi-8], eax
mov eax, [ec.ctx_RegEip] mov [esi-12], eax
;* ;* Put new stack pointer on stack. ;*
push ds sub esi, 12 push esi
;* ;* Reset other registers. ;*
mov edi, [ec.ctx_RegEdi] mov esi, [ec.ctx_RegEsi] mov ebx, [ec.ctx_RegEbx] mov edx, [ec.ctx_RegEdx] mov ecx, [ec.ctx_RegEcx] mov eax, [ec.ctx_RegEax] mov ds, [ec.ctx_SegDs] mov es, [ec.ctx_SegEs] mov fs, [ec.ctx_SegFs] mov gs, [ec.ctx_SegGs]
mov ebp, [ec.ctx_RegEbp] ; must do this last.
lss esp, fword ptr [esp] ; reset ss:esp
sti ; JWM, 9/3/91 push [esp+8] ; JWM, 9/6/91 popfd ; JWM, 9/6/91
iretd ; reset flags, cs, eip
ExceptNotHandled:EmExcept ENDP
endif ; ifdef NT386
int 3 ; Added For BBT, a return here is needed or BBT ret ; has a flow problem.ifdef DEBUG
lab PageFault mov al, byte ptr cs:[iax] retendif
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