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PAGE 60,150;***************************************************************************;* TIMER.ASM;*;* Routines used to give a cleaner interface to the VTD.;* This interface also works on a 286 by calling GetTickCount() in;* this case.;*;***************************************************************************
INCLUDE TOOLPRIV.INC INCLUDE WINDOWS.INC
;** SymbolsSI_CRITICAL EQU 1DI_CRITICAL EQU 2
;** ImportsexternA __WinFlagsexternFP GetTickCount
sBegin DATA
dwLastTimeReturned dd 0wLastCountDown dw 0
sEnd
sBegin CODE assumes CS,CODE assumes DS,DATA
; TimerCount; Returns the count from either the virtual timer device or from the; Windows function GetTickCount() depending on the processor.; Prototype:; BOOL FAR PASCAL TimerCount(; TIMERINFO FAR *lpTimer);
cProc TimerCount, <FAR,PUBLIC>, <si,di,ds> parmD lpTimer localD dwJumpAddrcBegin mov ax, _DATA ;Get our data segment mov es, ax
;** Point to the structure lds si,lpTimer ;Point to the structure
;** Make sure the size is correct xor ax,ax ;FALSE cmp WORD PTR [si].ti_dwSize[2],0 ;High word must be zero je @F jmp TC_End@@: cmp WORD PTR [si].ti_dwSize[0],SIZE TIMERINFO ;Low word must match je @F jmp TC_End@@:
ifndef WOW ;** If we are in standard mode, always use Windows entry point mov ax,__WinFlags ;Get the flags test ax,WF_STANDARD ;Standard mode? jnz TC_TryMMSys ;Yes, don't even try VTD.386p ;** Try to get the VTD entry point mov ax,1684h ;Get device entry point mov bx,5 ;VTD device number int 2fh ;Win386 entry point mov ax,es ;Did we get a value? or ax,di ; (zero means no device) jz SHORT TC_UseWinAPI ;No VTD--use Win API
;** Get the VTD values mov WORD PTR dwJumpAddr[0],di ;Save the address mov WORD PTR dwJumpAddr[2],es ;Save the address mov ax,0101h ;VTD: ms since start of Win386 call DWORD PTR dwJumpAddr ;Call the VTD jc SHORT TC_UseWinAPI ;Carry set means error mov [si].ti_dwmsSinceStart,eax ;Save in structure mov ax,0102h ;VTD: ms in this VM call DWORD PTR dwJumpAddr ;Call the VTD jc SHORT TC_UseWinAPI ;Carry set means VTD error mov [si].ti_dwmsThisVM,eax ;Save value in structure jmp TC_ReturnOK ;We're done.286p
;** See if mmsystem timer is installedTC_TryMMSys: cmp WORD PTR es:[lpfntimeGetTime][2], 0 ;Installed? je TC_UseWinAPI ;No, do this the hard way call DWORD PTR es:lpfntimeGetTime
;** Fill the structure with this information mov WORD PTR [si].ti_dwmsSinceStart[0],ax mov WORD PTR [si].ti_dwmsSinceStart[2],dx mov WORD PTR [si].ti_dwmsThisVM[0],ax mov WORD PTR [si].ti_dwmsThisVM[2],dx jmp TC_ReturnOKendif ; ndef WOW
;** Use the Windows APITC_UseWinAPI: cCall GetTickCount ;Call the Windows API mov WORD PTR [si].ti_dwmsSinceStart[0],ax ;Save the value for now mov WORD PTR [si].ti_dwmsSinceStart[2],dx
;** Read the countdown timer. Note that the timer starts at 54 * 1193 ;** and counts down to zero. Each count is 1193 ms.ifdef NEC_98; timer i/o access change push ds mov ax,40h ; 40:101 ;921006 mov ds,ax test byte ptr ds:[101h],80h ; system clock check ;921006 pop ds mov cx,2457 ; 2.5MHz jz @f mov cx,1996 ; 2MHz@@: push cx xor al,al ;Prepare to read tick count out 77h,al ;Send to timer ;921006 in al,dx ;Get the low byte mov ah,al ;Save in AH in al,dx ;Get the high byte xchg ah,al pop cx mov dx,0ffffh ;Get total countdown amount sub dx,ax ;Get number of counts expired mov ax,dx ;Get the number in AX for div xor dx,dx ;Zero the high wordelse ; NEC_98 xor al,al ;Prepare to read tick count out 43h,al ;Send to timer in al,40h ;Get the low byte mov ah,al ;Save in AH in al,40h ;Get the high byte xchg ah,al mov dx,0ffffh ;Get total countdown amount sub dx,ax ;Get number of counts expired mov ax,dx ;Get the number in AX for div xor dx,dx ;Zero the high word mov cx,1193 ;Divide to get msendif ; NEC_98 div cx ;Divide it mov cx, ax ;cx == saved Curr count
;** Now fill the structure. Note that the 'ThisVM' entry is the ;** same as the 'SinceStart' entry in standard mode. xor dx, dx add ax, WORD PTR [si].ti_dwmsSinceStart[0] ;Add this count in adc dx, WORD PTR [si].ti_dwmsSinceStart[2]
;** Check to make sure we didn't mess up. If we did (if the timer ;** was reset right in the middle of us reading it). If we ;** messed up, do it again until we get it right. mov bx, _DATA ;Get our data segment mov es, bx cmp dx, WORD PTR es:dwLastTimeReturned[2] jne TC_TimeOK cmp ax, WORD PTR es:dwLastTimeReturned[0] jae TC_TimeOK
; New time is less than the old time so estimate the curr time ; using LastTimeReturned as the base mov ax, WORD PTR es:dwLastTimeReturned[0] mov dx, WORD PTR es:dwLastTimeReturned[2]
xor bx, bx ;check for wrap cmp cx, word ptr es:wLastCountDown jae TC_NoWrap ;if wrap add ax, cx ; += curr count adc dx, 0 jmp short TC_TimeOK
TC_NoWrap: ;else no wrap mov bx, cx ; += Curr - LastCountDown sub bx, word ptr es:wLastCountDown add ax, bx adc dx, 0
TC_TimeOK: mov word ptr es:wLastCountDown, cx mov WORD PTR es:dwLastTimeReturned[0], ax mov WORD PTR es:dwLastTimeReturned[2], dx mov WORD PTR [si].ti_dwmsSinceStart[0], ax ;Save good count mov WORD PTR [si].ti_dwmsSinceStart[2], dx mov WORD PTR [si].ti_dwmsThisVM[0],ax ;Save in structure mov WORD PTR [si].ti_dwmsThisVM[2],dx ;Save in structure
TC_ReturnOK: mov ax,1 ;Return TRUE
TC_End:
cEnd
sEnd
END
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