102 lines
2.8 KiB
C
102 lines
2.8 KiB
C
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/****************************************************************************
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*
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* capdriv.c
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*
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* Smartdrv control.
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*
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* Microsoft Video for Windows Sample Capture Class
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*
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* Copyright (c) 1992, 1993 Microsoft Corporation. All Rights Reserved.
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*
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* You have a royalty-free right to use, modify, reproduce and
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* distribute the Sample Files (and/or any modified version) in
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* any way you find useful, provided that you agree that
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* Microsoft has no warranty obligations or liability for any
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* Sample Application Files which are modified.
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*
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***************************************************************************/
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#include <windows.h>
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#include <windowsx.h>
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#pragma optimize ("", off)
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// SD_CACHE_DRIVE:
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// FUNCTION:
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// Enables and disables read or write caching for a particular
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// drive unit. Returns the cache state of the drive in DL. Get
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// takes no action, but simply returns cache state for drive unit
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// in DL.
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//
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// INPUT:
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// AX=MULT_SMARTDRV (4A10h)
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// BX=SD_CACHE_DRIVE (3)
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// DL=CACHE_DRIVE_<get,read|write enable|disable>
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// BP=unit number of drive
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// OUTPUT:
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// DL=cache state of unit:
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// Bit 7 set -> no caching enabled for this unit
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// Bit 7 not set -> read caching enabled for this unit
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// Bit 6 set -> write caching not enabled for this unit
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// Bit 6 not set -> write caching enabled for this unit
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// -1 -> not a cachable drive
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// USES:
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// ALL except DS,ES
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//
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#define MULT_SMARTDRV 0x4a10
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#define SD_CACHE_DRIVE 3
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#define CACHE_DRIVE_GET 0
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#define CACHE_DRIVE_READ_ENABLE 1
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#define CACHE_DRIVE_READ_DISABLE 2
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#define CACHE_DRIVE_WRITE_ENABLE 3
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#define CACHE_DRIVE_WRITE_DISABLE 4
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#define F_WRITE_CACHE (1 << 7)
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#define F_READ_CACHE (1 << 6)
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WORD NEAR PASCAL SmartDrvCache(int iDrive, BYTE cmd)
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{
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WORD w;
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_asm {
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push bp
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mov ax, MULT_SMARTDRV
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mov bx, SD_CACHE_DRIVE
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mov dl, cmd
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mov bp, iDrive
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int 2fh
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mov al,dl
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xor ah,ah
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pop bp
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mov w,ax
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}
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return w;
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}
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WORD FAR PASCAL SmartDrv(char chDrive, WORD w)
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{
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WORD wCur;
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int iDrive;
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iDrive = (chDrive | 0x20) - 'a';
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wCur = SmartDrvCache(iDrive, CACHE_DRIVE_GET);
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if (w & F_WRITE_CACHE)
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SmartDrvCache(iDrive, CACHE_DRIVE_WRITE_DISABLE);
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else
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SmartDrvCache(iDrive, CACHE_DRIVE_WRITE_ENABLE);
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if (w & F_READ_CACHE)
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SmartDrvCache(iDrive, CACHE_DRIVE_READ_DISABLE);
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else
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SmartDrvCache(iDrive, CACHE_DRIVE_READ_ENABLE);
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return wCur;
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}
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#pragma optimize ("", on)
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