571 lines
15 KiB
NASM
571 lines
15 KiB
NASM
;
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;
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; Copyright (C) Microsoft Corporation, 1987
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;
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; This Module contains Proprietary Information of Microsoft
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; Corporation and should be treated as Confidential.
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;
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;
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page ,132
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title emoem.asm - OEM dependent code for 8087
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;--------------------------------------------------------------------
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;
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; OEM customization routines for 8087/80287 coprocessor
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;
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; This module is designed to work with the following
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; Microsoft language releases:
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;
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; Microsoft Quick BASIC 4.0 and later
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; Microsoft Quick BASIC (KANJI) 4.0 and later
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; Microsoft BASCOM 3.0
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; Microsoft BASCOMK 3.0
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; Microsoft BASCOM/2
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; Microsoft BASCOMK/2
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;
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; This module supersedes the OEMR7.ASM module used in earlier
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; versions of Microsoft FORTRAN 77 and Pascal. The documentation
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; provided with the FORTRAN and Pascal releases refers to the old
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; OEMR7.ASM module and is only slightly relevant to this module.
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;
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; The following routines need to be written to properly handle the
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; 8087/808287 installation, termination, and interrupt handler
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;
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; __FPINSTALL87 install 8087 interrupt handler
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; __FPTERMINATE87 deinstall 8087 interrupt handler
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; __fpintreset reset OEM hardware if an 8087 interrupt
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;
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; ***** NEW INSTRUCTIONS *****
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;
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; If you want a PC clone version, do nothing. The libraries are
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; setup for working on IBM PC's and clones.
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;
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; This instructions only need to be followed if a non-IBM PC
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; clone version is desired.
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;
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; This module should be assembled with the
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; Microsoft Macro Assembler Version 4.00 or later as follows:
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;
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; masm -DOEM -r emoem.asm;
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;
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; For QuickBASIC, assemble as follows:
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;
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; masm -D_QB -DOEM -r emoem.asm;
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;
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; Most hardware handles the 8087/80287 in one of the following
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; three ways -
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;
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; 1. NMI - IBM PC and clones all handle the interrupt this way
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; 2. single 8259
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; 3. master/slave 8259
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;
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; Manufacturer specific initialization is supported for these 3
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; machine configurations either by modifying this file and replacing
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; the existing EMOEM module in the math libraries or by patching
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; the .LIB and .EXE files directly.
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;
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; LIB 87-+EMOEM;
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; LIB EM-+EMOEM;
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;
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;--------------------------------------------------------------------
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ifdef OEM
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if1
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%out OEM version for non-clone support
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endif
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endif
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ifndef _QB
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_HOOK_CTRLC=1
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endif
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ifdef _HOOK_CTRLC
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if1
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%out Non-QB version. Hooks Ctrl-C. Hooks INT 75h.
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endif
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else
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if1
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%out QB version. Doesn't hook Ctrl-C. Hooks INT 75h.
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endif
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endif
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;---------------------------------------------------------------------
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; Assembly constants.
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;---------------------------------------------------------------------
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; MS-DOS OS calls
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OPSYS EQU 21H
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SETVECOP EQU 25H
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GETVECOP EQU 35H
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DOSVERSION EQU 30h
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ifdef _HOOK_CTRLC
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CTLCVEC EQU 23h
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endif ;_HOOK_CTRLC
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EMULATOR_DATA segment public 'FAR_DATA'
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assume ds:EMULATOR_DATA
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; User may place data here if DS is setup properly.
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; Recommend keeping the data items in the code segment.
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EMULATOR_DATA ends
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EMULATOR_TEXT segment public 'CODE'
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assume cs:EMULATOR_TEXT
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public __FPINSTALL87 ; DO NOT CHANGE THE CASE ON
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public __FPTERMINATE87 ; THESE PUBLIC DEFINITIONS
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extrn __FPEXCEPTION87:near ; DO NOT CHANGE CASE
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ifdef OEM
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;***********************************************************************
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;
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; Hardware dependent parameters in the 8087 exception handler.
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;
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; For machines using 2 8259's to handle the 8087 exception, be sure that
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; the slave 8259 is the 1st below and the master is the 2nd.
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;
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; The last 4 fields allow you to enable extra interrupt lines into the
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; 8259s. It should only be necessary to use these fields if the 8087
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; interrupt is being masked out by the 8259 PIC.
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;
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; The ocw2's (EOI commands) can be either non-specific (20H) or
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; specific (6xH where x=0 to 7). If you do not know which interrupt
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; request line on the 8259 the 8087 exception uses, then you should issue
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; the non-specific EOI (20H). Interrupts are off at this point in the
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; interrupt handler so a higher priority interrupt will not be seen.
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oeminfo struc
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oemnum db 0 ; MS-DOS OEM number (IBM is 00h)
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intnum db 2 ; IBM PC clone interrupt number
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share db 0 ; nonzero if original vector should be taken
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a8259 dw 0 ; 1st 8259 (A0=0) port #
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aocw2 db 0 ; 1st 8259 (A0=0) EOI command
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b8259 dw 0 ; 2nd 8259 (A0=0) port #
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bocw2 db 0 ; 2nd 8259 (A0=0) EOI command
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a8259m dw 0 ; 1st 8259 (A0=1) port #
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aocw1m db 0 ; 1st 8259 (A0=1) value to mask against IMR
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b8259m dw 0 ; 2nd 8259 (A0=1) port #
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bocw1m db 0 ; 2nd 8259 (A0=1) value to mask against IMR
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oeminfo ends
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;-----------------------------------------------------------------------
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; OEM specific 8087 information
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;
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; If the OEM number returned from the DOS version call matches,
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; this information is automatically moved into the oem struc below.
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oemtab label byte ; Table of OEM specific values for 8087
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; OEM#, int, shr, a59, acw2,b59, bcw2,a59m,acw1,b59m,bcw1
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;TI Professional Computer
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TI_prof oeminfo <028h,047h,000h,018h,020h,0000,0000,0000,0000,0000,0000>
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db 0 ; end of table
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; Unique pattern that can be searched for with the debugger so that
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; .LIB or .EXE files can be patched with the correct values.
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; If new values are patched into .LIB or .EXE files, care must be
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; taken in insure the values are correct. In particular, words and
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; bytes are intermixed in oeminfo structure. Remember words are
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; stored low byte - high byte in memory on the 8086 family.
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db '<<8087>>' ; older versions used '<8087>'
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; Some manufacturer's machines can not be differentiated by the
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; OEM number returned by the MS-DOS version check system call.
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; For these machines it is necessary to replace the line below
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oem1 oeminfo <> ; default values for IBM PC & clones
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; with one of the following. If your machine has an 8087 capability
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; and it is not in the list below, you should contact your hardware
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; manufacturer for the necessary information.
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;ACT Apricot
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;oem1 oeminfo <000h,055h,000h,000h,020h,000h,000h,000h,000h,000h,000h>
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;NEC APC3 and PC-9801 (OEM number returned by NEC MS-DOS's is different)
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;oem1 oeminfo <000h,016h,000h,008h,066h,000h,067h,00Ah,0BFh,002h,07Fh>
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;---------------------------------------------------------------------
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aoldIMR db 0 ; 1st 8259 original IMR value
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boldIMR db 0 ; 2nd 8259 original IMR value
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endif ;OEM
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statwd dw 0 ; Temporary for status word
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oldvec dd 0 ; Old value in 8087 exception interrupt vector
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ifdef _HOOK_CTRLC
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ctlc dd 0 ; Old value of Control-C vector (INT 23h)
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endif ;_HOOK_CTRLC
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ifndef OEM
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oldvec75 dd 0 ; Old value INT 75H interrupt vector
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INT75FLAGS DW 0 ; flags at INT 75 time
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INT75CS DW 0 ; CS at INT 75 time
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INT75IP DW 0 ; IP at INT 75 time
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INT75VEC DW OFFSET FPREALINT2 ; place INT 75 IRETs to
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endif ;OEM
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page
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;---------------------------------------------------------------------
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;
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; Perform OEM specific initialization of the 8087.
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;
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__FPINSTALL87:
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push ds ; DS = EMULATOR_DATA
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push cs ; Move current CS to DS for opsys calls.
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pop ds
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assume ds:EMULATOR_TEXT
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ifdef OEM
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push ds
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pop es ; CS = DS = ES
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mov ah,DOSVERSION
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int OPSYS ; bh = OEM#
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cld
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mov si,offset oemtab ; start of OEM 8087 info table
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mov di,offset oem1+1
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mov cx,(size oem1)-1
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OEMloop:
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lodsb ; get OEM#
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or al,al
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jz OEMdone ; OEM# = 0 - did not find OEM
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cmp al,bh ; correct OEM#
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je OEMfound
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add si,cx ; skip over OEM information
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jmp OEMloop
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OEMfound:
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rep movsb ; move the information
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OEMdone: ; done with automatic customization
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endif ;OEM
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; Save old interrupt vector.
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; Ask operating system for vector.
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ifdef OEM
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mov al,[oem1].intnum ; Interrupt vector number.
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mov ah,GETVECOP ; Operating system call interrupt.
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int OPSYS ; Call operating system.
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mov word ptr [oldvec],bx ; Squirrel away old vector.
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mov word ptr [oldvec+2],es
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else
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mov ax,GETVECOP shl 8 + 75H ; get interrupt vector 75H
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int OPSYS ; Call operating system.
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mov word ptr [oldvec75],bx ; Squirrel away old vector.
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mov word ptr [oldvec75+2],es;
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mov ax,GETVECOP shl 8 + 2 ; get interrupt vector 2
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int OPSYS ; Call operating system.
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mov word ptr [oldvec],bx ; Squirrel away old vector.
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mov word ptr [oldvec+2],es
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endif ;OEM
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; Have operating system install interrupt vectors.
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ifdef OEM
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mov dx,offset __fpinterrupt87 ; Load DX with 8087 interrupt handler.
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mov ah,SETVECOP ; Set interrupt vector code in AH.
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mov al,[oem1].intnum ; Set vector number.
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int OPSYS ; Install vector.
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else
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mov dx,offset __fpinterrupt87 ; Load DX with 8087 interrupt handler.
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mov ax,SETVECOP shl 8 + 2 ; set interrupt vector 2
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int OPSYS ; Install vector.
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mov dx,offset __fpinterrupt75 ; Load DX with 8087 interrupt handler.
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mov ax,SETVECOP shl 8 + 75H ; set interrupt vector 75
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int OPSYS ; Install vector.
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endif ;OEM
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; Intercept Control-C vector to guarentee cleanup
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ifdef _HOOK_CTRLC ;
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mov ax,GETVECOP shl 8 + CTLCVEC
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int OPSYS
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mov word ptr [ctlc],bx
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mov word ptr [ctlc+2],es
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mov dx,offset ctlcexit
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mov ax,SETVECOP shl 8 + CTLCVEC
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int OPSYS
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endif ;_HOOK_CTRLC
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ifdef OEM
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; set up 8259's so that 8087 interrupts are enabled
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mov ah,[oem1].aocw1m ; get mask for 1st 8259 IMR
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or ah,ah ; if 0, don't need to do this
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jz installdone ; and only 1 8259
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mov dx,[oem1].a8259m ; get port number for 1st 8259 (A0=1)
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in al,dx ; read old IMR value
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mov [aoldIMR],al ; save it to restore at termination
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and al,ah ; mask to enable interrupt
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jmp short $+2 ; for 286's
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out dx,al ; write out new mask value
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mov ah,[oem1].bocw1m ; get mask for 2nd 8259 IMR
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or ah,ah ; if 0, don't need to do this
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jz installdone ;
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mov dx,[oem1].b8259m ; get port number for 2nd 8259 (A0=1)
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in al,dx ; read old IMR value
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mov [boldIMR],al ; save it to restore at termination
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and al,ah ; mask to enable interrupt
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jmp short $+2 ; for 286's
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out dx,al ; write out new mask value
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installdone:
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endif ;OEM
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assume ds:EMULATOR_DATA
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pop ds
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ret
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page
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; __FPTERMINATE87
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;
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; This routine should do the OEM 8087 cleanup. This routine is called
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; before the program exits.
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;
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; DS = EMULATOR_DATA
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__FPTERMINATE87:
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push ds
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push ax
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push dx
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ifdef OEM
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mov ah,SETVECOP
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mov al,[oem1].intnum
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lds dx,[oldvec]
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int OPSYS
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else
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mov ax,SETVECOP shl 8 + 2
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lds dx,[oldvec]
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int OPSYS
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mov ax,SETVECOP shl 8 + 75H ; restore int 75
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lds dx,[oldvec75] ;
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int OPSYS ;
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endif ;OEM
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ifdef OEM
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; reset 8259 IMR's to original state
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push cs
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pop ds ; DS = CS
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assume ds:EMULATOR_TEXT
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cmp [oem1].aocw1m,0 ; did we have to change 1st 8259 IMR
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je term2nd8259 ; no - check 2nd 8259
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mov al,[aoldIMR] ; get old IMR
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mov dx,[oem1].a8259m ; get 1st 8259 (A0=1) port #
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out dx,al ; restore IMR
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term2nd8259:
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cmp [oem1].bocw1m,0 ; did we have to change 2nd 8259 IMR
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je terminatedone ; no
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mov al,[boldIMR] ; get old IMR
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mov dx,[oem1].b8259m ; get 2nd 8259 (A0=1) port #
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out dx,al ; restore IMR
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terminatedone:
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endif ;OEM
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pop dx
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pop ax
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pop ds
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assume ds:EMULATOR_DATA
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ret
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ifdef _HOOK_CTRLC
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; Forced cleanup of 8087 exception handling on Control-C
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ctlcexit:
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push ax
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push dx
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push ds
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call __FPTERMINATE87 ; forced cleanup of exception handler
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lds dx,[ctlc] ; load old control C vector
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mov ax,SETVECOP shl 8 + CTLCVEC
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int OPSYS
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pop ds
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pop dx
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pop ax
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jmp [ctlc] ; go through old vector
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endif ;_HOOK_CTRLC
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page
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;
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; __fpinterrupt75
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;
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; This is the "real" 80x87 interrupt routine for AT's and clones.
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; Entire routine added [2].
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;
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; We hook INT 75 in order to work around a DOS nuance that otherwise causes the
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; exception handler to get executed with the wrong stack segment.
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;
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; In PC's, a math exception is a simple INT 2, which since we hook, we recieve
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; unobstructed. On AT's, an INT 75H is generated, which is normally trapped by
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; the BIOS, which performs some hardware magic, and then executes an INT 2
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; instruction to simulate the PC's behaviour. Hooking INT 2 alone is sufficient
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; to handle these two cases.
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;
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; In MS-DOS (and PC-DOS) versions 3.2x, a stack swapping scheme is employed in
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; which the DOS actually allocates a new SS:SP before executing the interrupt
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; handler. If we do not hook INT 75H, then it gets a new SS:SP, and executes
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; the INT 2 with that stack, and we cannot look back on the stack for our
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; context, nor can we really know anything about the stack at the time of the
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; exception.
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;
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; The process used to over come this problem is, essentially, to allow the
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; INT 75H to execute, including it's embedded INT 2, but to do nothing in that
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; INT 2. We fake the INT 75H return, though, such that it returns to us, (with
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; the right stack to boot), and we can continue to process the exception.
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;
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; The steps invoved:
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;
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; 1) Hook BOTH INT 2 and INT 75H
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;
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; 2) On an INT 75, save the CS, IP and FLAGS of the return address, and REPLACE
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; THEM with values that will cause the INT 75H's IRET to return step 5,
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; below.
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;
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; 3) Just jump to the previous INT 75H handler.
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;
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; 4) On the subsequent INT 2, IF there is a CS as saved in step 1, then do
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; nothing. Just IRET. If there is not saved CS, then we have a plain old
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; INT 2 (running on an XT, most likely), and we just go to step 6.
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;
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; 5) On return from the INT 75H, we have the SS:SP at the time of the
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; exception. Just push the previously saved FLAGS, CS and IP of the
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; exception, clear the saved CS, and fall into....
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;
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; 6) A normal INT 2 handler.
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;
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ifndef OEM ;
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__fpinterrupt75:
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ASSUME DS:NOTHING
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POP CS:[INT75IP] ;Squirel away exception address
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POP CS:[INT75CS]
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POP CS:[INT75FLAGS]
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PUSHF ;Set up INT 75 to return to our code
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PUSH CS
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PUSH CS:[INT75VEC]
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JMP [oldvec75] ;And execute original INT 75H
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endif ; ifndef OEM
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;
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; __fpinterrupt87
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;
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; This is the 8087 exception interrupt routine.
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;
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; All OEM specific interrupt and harware handling should be done in
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; __fpintreset because __FPEXCEPTION87 (the OEM independent 8087
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; exception handler) may not return. __FPEXCEPTION87 also turns
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; interrupts back on.
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;
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PENDINGBIT= 80h ; Bit in status word for interrupt pending
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__fpinterrupt87:
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assume ds:nothing
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nop
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fnstsw [statwd] ; Store out exceptions
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ifndef OEM ;
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TEST CS:[INT75CS],-1 ; has INT 75 ocurred?
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JZ FPWASINT2 ; jump if not
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IRET ; just return to original INT 75 handler
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FPREALINT2: ; INT 75 IRETs here
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PUSH CS:[INT75FLAGS] ; fake up original exception
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PUSH CS:[INT75CS] ;
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PUSH CS:[INT75IP] ;
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MOV CS:[INT75CS],0 ; and clear the INT75 occurred flag.
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FPWASINT2: ;
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endif ; ifndef OEM
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push cx ; waste time
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mov cx,3
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self:
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loop self
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pop cx
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test byte ptr [statwd],PENDINGBIT ; Test for 8087 interrupt
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jz not87int ; Not an 8087 interrupt.
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ifdef OEM
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call __fpintreset ; OEM interrupt reset routine
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endif ;OEM
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call __FPEXCEPTION87 ; 8087 error handling - may not return
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; this routine turns interrupts back on
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ifdef OEM
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cmp [oem1].share,0 ; Should we execute the old interrupt routine?
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jz done8087 ; if not then return
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|
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; If you fall through here to do further hardware resetting, things
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|
; may not always work because __FPEXCEPTION87 does not always return
|
|
; This only happens when the 8087 handler gets an exception that is
|
|
; a fatal error in the language runtimes. I.e., divide by zero
|
|
; is a fatal error in all the languages, unless the control word has
|
|
; set to mask out divide by zero errors.
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|
|
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else ;
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iret ;
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endif ;OEM
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|
|
|
not87int:
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|
jmp [oldvec] ; We should never return from here.
|
|
|
|
|
|
ifdef OEM
|
|
|
|
done8087:
|
|
iret
|
|
|
|
|
|
__fpintreset:
|
|
push ax
|
|
push dx
|
|
mov al,[oem1].aocw2 ; Load up EOI instruction.
|
|
or al,al ; Is there at least one 8259 to be reset?
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|
jz Reset8259ret ; no
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|
mov dx,[oem1].a8259
|
|
out dx,al ; Reset (master) 8259 interrupt controller.
|
|
mov al,[oem1].bocw2 ; Load up EOI instruction.
|
|
or al,al ; Is there a slave 8259 to be reset?
|
|
jz Reset8259ret
|
|
mov dx,[oem1].b8259
|
|
out dx,al ; Reset slave 8259 interrupt controller.
|
|
|
|
Reset8259ret:
|
|
pop dx
|
|
pop ax
|
|
ret
|
|
|
|
endif ;OEM
|
|
|
|
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EMULATOR_TEXT ends
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|
|
|
end
|