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Diffstat (limited to 'private/mvdm/inc/vint.h')
| -rw-r--r-- | private/mvdm/inc/vint.h | 177 |
1 files changed, 177 insertions, 0 deletions
diff --git a/private/mvdm/inc/vint.h b/private/mvdm/inc/vint.h new file mode 100644 index 000000000..460374aee --- /dev/null +++ b/private/mvdm/inc/vint.h @@ -0,0 +1,177 @@ +/*++ BUILD Version: 0001 + +Copyright (c) 1990 Microsoft Corporation + +Module Name: + + VINT.H + +Abstract: + + This module contains macro support for manipulating virtual + interrupt bit from v86 mode and 16bit protect mode. FCLI/FST/FIRET + result in exact behavior of these instructions on the chip without + trapping. + +Author: + + Sudeepb 08-Dec-1992 Created + +Revision History: + sudeepb 16-Mar-1993 added FIRET + +--*/ + +/* +See \nt\private\inc\vdm.h for a complete list +of the NTVDM state flag bit definitions + +INTERRUPT_PENDING_BIT - set if interrupts pending +VIRTUAL_INTERRUPT_BIT - This bit always correctly reflects the interrupt + disbale/enable state of the vDM while in 16bit land. + +MIPS_BIT_MASK - tells whether VDM is running on x86/mips +EXEC_BIT_MASK - tells if DOS is in int21/exec operation. +*/ + +#define INTERRUPT_PENDING_BIT 0x0003 +#define VIRTUAL_INTERRUPT_BIT 0x0200 + +#define MIPS_BIT_MASK 0x400 +#define EXEC_BIT_MASK 0x800 +#define RM_BIT_MASK 0x1000 +#define RI_BIT_MASK 0x2000 + +#define FIXED_NTVDMSTATE_SEGMENT 0x70 +#define FIXED_NTVDMSTATE_OFFSET 0x14 +#define FIXED_NTVDMSTATE_LINEAR ((FIXED_NTVDMSTATE_SEGMENT << 4) + FIXED_NTVDMSTATE_OFFSET) +#define FIXED_NTVDMSTATE_REL40 0x314 + +#define FIXED_NTVDMSTATE_SIZE 4 +#define NTIO_LOAD_SEGMENT 0x70 +#define NTIO_LOAD_OFFSET 0 +#define pNtVDMState ((PULONG)FIXED_NTVDMSTATE_LINEAR) + +#define VDM_TIMECHANGE 0x00400000 + +/* ASM +; FCLI macro should be used in v86mode/16bit preotect mode code to replace +; costly cli's. Please note that this macro could destroy the Overflow +; bit in the flag. + +FCLI macro + local a,b,c + push ds + push ax + mov ax,40h + mov ds,ax + lahf + test word ptr ds:FIXED_NTVDMSTATE_REL40, MIPS_BIT_MASK OR RI_BIT_MASK + jnz short b + lock and word ptr ds:FIXED_NTVDMSTATE_REL40,NOT VIRTUAL_INTERRUPT_BIT +a: + sahf + pop ax + pop ds + jmp short c +b: + cli + jmp short a +c: +endm + +; +; FSTI macro should be used in v86mode or 16bit protectmode code to replace +; costly sti's. Please note that this macro could destroy the Overflow bit +; in the flag. + +FSTI macro + local a,b,c + push ds + push ax + mov ax,40h + mov ds,ax + lahf + test word ptr ds:FIXED_NTVDMSTATE_REL40, INTERRUPT_PENDING_BIT + jnz short b + test word ptr ds:FIXED_NTVDMSTATE_REL40, MIPS_BIT_MASK OR RI_BIT_MASK + jnz short b + lock or word ptr ds:FIXED_NTVDMSTATE_REL40, VIRTUAL_INTERRUPT_BIT +a: + sahf + pop ax + pop ds + jmp short c +b: + sti + jmp short a +c: +endm + +FIRET MACRO + local a,b,d,e,f,g,i,j,k + push ds + push ax + +;; Do real IRET on MIPS or if interrupts are pending + + mov ax,40h + mov ds,ax + test word ptr ds:FIXED_NTVDMSTATE_REL40, MIPS_BIT_MASK OR RI_BIT_MASK + jnz short b + +;; running on x86 can assume 386 or above instructions + push bp + mov bp,sp + mov ax,[bp+10] ; get flags + pop bp + test ax,100h ; test if trap flag is set + jnz short b ; if so, do iret + + test ax,200h ; test if interrupt flag is set + jz short i ; ZR -> flag image has IF not set + lock or word ptr ds:FIXED_NTVDMSTATE_REL40, VIRTUAL_INTERRUPT_BIT + test word ptr ds:FIXED_NTVDMSTATE_REL40, INTERRUPT_PENDING_BIT + jnz short b +j: + xchg ah,al ; AH=low byte AL=high byte + cld + test al,4 ; check direction flag + jnz short d ; +e: + test al,8 ; check overflow flag + jnz short f ; go to f if flag image has OF set + jo short k ; go to k to reset OF +g: + sahf ; set low byte of flags from ah + pop ax + pop ds + retf 2 ; IRET and discard flags +i: + lock and word ptr ds:FIXED_NTVDMSTATE_REL40,NOT VIRTUAL_INTERRUPT_BIT + jmp short j +f: + jo short g ; all OK if OF bit set in real flag + ; set the overflow bit in real flag + push ax + mov al,127 + add al,2 ; will set OF + pop ax + jmp short g + +k: + ; reset the OF + push ax + xor al,al ; will reset OF + pop ax + jmp short g +d: + std + jmp short e +b: + pop ax + pop ds + iret +endm + + */ |