129 lines
3.9 KiB
NASM
129 lines
3.9 KiB
NASM
PAGE ,132
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TITLE NTNPXEM.ASM -- Support for fielding exceptions from npx em
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; Copyright (c) Microsoft Corporation 1988-1991. All Rights Reserved.
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;****************************************************************
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;* *
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;* NTNPXEM.ASM - Exception handler for npx emulation *
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;* *
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;****************************************************************
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;* *
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;* Module Description: *
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;* This module contains code to field exceptions from the *
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;* Nt NPX emulator. These exceptions will only be *
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;* received on machines without 387's, on which the app *
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;* has set the EM bit. *
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;****************************************************************
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.286p
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.287
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; -------------------------------------------------------
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; INCLUDE FILE DEFINITIONS
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; -------------------------------------------------------
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.xlist
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.sall
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include segdefs.inc
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include gendefs.inc
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include pmdefs.inc
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include ks386.inc
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include intmac.inc
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.list
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; -------------------------------------------------------
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; GENERAL SYMBOL DEFINITIONS
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; -------------------------------------------------------
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; -------------------------------------------------------
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; EXTERNAL SYMBOL DEFINITIONS
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; -------------------------------------------------------
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extrn PmFaultEntryVector:near
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; -------------------------------------------------------
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; DATA SEGMENT DEFINITIONS
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; -------------------------------------------------------
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DXDATA segment
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extrn rgw0stack:word
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DXDATA ends
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; -------------------------------------------------------
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; Exception Handler
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; -------------------------------------------------------
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DXPMCODE segment
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assume cs:DXPMCODE
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.386p
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;
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; N.B. The following routine will be executed on a special
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; code selector. The following routine must ALWAYS
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; appear at offset zero in this code selector.
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;
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; -------------------------------------------------------
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; NpxExceptionHandler -- This function switches to the
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; exception handler stack, pushes an exception frame,
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; and restores the registers. It then transfers control
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; the trap 7 fault handler.
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;
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; Input: ss:esp -> an NT CONTEXT record
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; Output: all registers restored to fault time
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; values, and exception frame pushed.
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; Errors: none
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; Uses: all
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assume ds:NOTHING,es:NOTHING,ss:NOTHING,fs:NOTHING
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public NpxExceptionHandler,EndNpxExceptionHandler
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NpxExceptionHandler proc far
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FCLI
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mov ax,ss
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mov ds,ax
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mov ebx,esp ; ds:ebx->CONTEXT
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mov ax,SEL_DXDATA OR STD_RING
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mov ss,ax
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mov esp,offset DXDATA:rgw0Stack ; ss:esp->exception stack
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;
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; Push exception frame on exception stack
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;
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movzx eax,word ptr [ebx].CsSegSs
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push eax
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push dword ptr [ebx].CsEsp
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push dword ptr [ebx].CsEFlags
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movzx eax,word ptr [ebx].CsSegCs
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push eax
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push dword ptr [ebx].CsEip
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;
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; Restore registers
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;
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mov gs,[ebx].CsSegGs
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mov fs,[ebx].CsSegFs
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mov es,[ebx].CsSegEs
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mov ebp,[ebx].CsEbp
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mov edi,[ebx].CsEdi
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mov esi,[ebx].CsEsi
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mov edx,[ebx].CsEdx
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mov ecx,[ebx].CsEcx
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mov ax,[ebx].CsSegDs
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push ax
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push dword ptr [ebx].CsEbx
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mov eax,[ebx].CsEax
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pop ebx
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pop ds
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db 0eah
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dw (offset PmFaultEntryVector + 21)
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dw SEL_DXPMCODE OR STD_RING
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EndNpxExceptionHandler:
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NpxExceptionHandler endp
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DXPMCODE ends
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end
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