191 lines
4.8 KiB
C
191 lines
4.8 KiB
C
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/*++ BUILD Version: 0001
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Copyright (c) 1990 Microsoft Corporation
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Module Name:
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VINT.H
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Abstract:
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This module contains macro support for manipulating virtual
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interrupt bit from v86 mode and 16bit protect mode. FCLI/FST/FIRET
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result in exact behavior of these instructions on the chip without
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trapping.
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Author:
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Sudeepb 08-Dec-1992 Created
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Revision History:
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sudeepb 16-Mar-1993 added FIRET
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--*/
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/*
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See \nt\private\inc\vdm.h for a complete list
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of the NTVDM state flag bit definitions
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INTERRUPT_PENDING_BIT - set if interrupts pending
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VIRTUAL_INTERRUPT_BIT - This bit always correctly reflects the interrupt
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disbale/enable state of the vDM while in 16bit land.
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MIPS_BIT_MASK - tells whether VDM is running on x86/mips
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EXEC_BIT_MASK - tells if DOS is in int21/exec operation.
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*/
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#define INTERRUPT_PENDING_BIT 0x0003
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#define VDM_INTS_HOOKED_IN_PM 0x0004
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#define VIRTUAL_INTERRUPT_BIT 0x0200
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#define MIPS_BIT_MASK 0x400
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#define EXEC_BIT_MASK 0x800
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#define RM_BIT_MASK 0x1000
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#define RI_BIT_MASK 0x2000
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#if defined(NEC_98)
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#define FIXED_NTVDMSTATE_SEGMENT 0x60
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#else // !NEC_98
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#define FIXED_NTVDMSTATE_SEGMENT 0x70
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#endif // !NEC_98
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#define FIXED_NTVDMSTATE_OFFSET 0x14
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#define FIXED_NTVDMSTATE_LINEAR ((FIXED_NTVDMSTATE_SEGMENT << 4) + FIXED_NTVDMSTATE_OFFSET)
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#if defined(NEC_98)
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#define FIXED_NTVDMSTATE_REL40 0x214
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#else // !NEC_98
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#define FIXED_NTVDMSTATE_REL40 0x314
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#endif // !NEC_98
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#define FIXED_NTVDMSTATE_SIZE 4
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#if defined(NEC_98)
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#define NTIO_LOAD_SEGMENT 0x60
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#else // !NEC_98
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#define NTIO_LOAD_SEGMENT 0x70
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#endif // !NEC_98
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#define NTIO_LOAD_OFFSET 0
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#define pNtVDMState ((PULONG)FIXED_NTVDMSTATE_LINEAR)
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#define VDM_TIMECHANGE 0x00400000
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/* ASM
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; FCLI macro should be used in v86mode/16bit preotect mode code to replace
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; costly cli's. Please note that this macro could destroy the Overflow
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; bit in the flag.
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FCLI macro
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local a,b,c
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push ds
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push ax
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mov ax,40h
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mov ds,ax
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lahf
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test word ptr ds:FIXED_NTVDMSTATE_REL40, MIPS_BIT_MASK OR RI_BIT_MASK
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jnz short b
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lock and word ptr ds:FIXED_NTVDMSTATE_REL40,NOT VIRTUAL_INTERRUPT_BIT
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a:
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sahf
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pop ax
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pop ds
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jmp short c
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b:
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cli
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jmp short a
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c:
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endm
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;
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; FSTI macro should be used in v86mode or 16bit protectmode code to replace
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; costly sti's. Please note that this macro could destroy the Overflow bit
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; in the flag.
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FSTI macro
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local a,b,c
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push ds
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push ax
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mov ax,40h
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mov ds,ax
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lahf
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test word ptr ds:FIXED_NTVDMSTATE_REL40, INTERRUPT_PENDING_BIT
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jnz short b
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test word ptr ds:FIXED_NTVDMSTATE_REL40, MIPS_BIT_MASK OR RI_BIT_MASK
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jnz short b
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lock or word ptr ds:FIXED_NTVDMSTATE_REL40, VIRTUAL_INTERRUPT_BIT
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a:
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sahf
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pop ax
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pop ds
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jmp short c
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b:
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sti
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jmp short a
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c:
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endm
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FIRET MACRO
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local a,b,d,e,f,g,i,j,k
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push ds
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push ax
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;; Do real IRET on MIPS or if interrupts are pending
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mov ax,40h
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mov ds,ax
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test word ptr ds:FIXED_NTVDMSTATE_REL40, MIPS_BIT_MASK OR RI_BIT_MASK
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jnz short b
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;; running on x86 can assume 386 or above instructions
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push bp
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mov bp,sp
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mov ax,[bp+10] ; get flags
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pop bp
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test ax,100h ; test if trap flag is set
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jnz short b ; if so, do iret
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test ax,200h ; test if interrupt flag is set
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jz short i ; ZR -> flag image has IF not set
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lock or word ptr ds:FIXED_NTVDMSTATE_REL40, VIRTUAL_INTERRUPT_BIT
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test word ptr ds:FIXED_NTVDMSTATE_REL40, INTERRUPT_PENDING_BIT
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jnz short b
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j:
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xchg ah,al ; AH=low byte AL=high byte
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cld
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test al,4 ; check direction flag
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jnz short d ;
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e:
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test al,8 ; check overflow flag
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jnz short f ; go to f if flag image has OF set
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jo short k ; go to k to reset OF
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g:
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sahf ; set low byte of flags from ah
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pop ax
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pop ds
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retf 2 ; IRET and discard flags
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i:
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lock and word ptr ds:FIXED_NTVDMSTATE_REL40,NOT VIRTUAL_INTERRUPT_BIT
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jmp short j
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f:
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jo short g ; all OK if OF bit set in real flag
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; set the overflow bit in real flag
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push ax
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mov al,127
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add al,2 ; will set OF
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pop ax
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jmp short g
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k:
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; reset the OF
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push ax
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xor al,al ; will reset OF
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pop ax
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jmp short g
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d:
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std
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jmp short e
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b:
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pop ax
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pop ds
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iret
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endm
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*/
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