tools/PacketVxD/lock.c

   1 /*
   2  * lock.c
   3  *
   4  * Ethernet Packet Interface to NDIS drivers.
   5  *
   6  * Copyright 1998 Equivalence Pty. Ltd.
   7  *
   8  * Original code by William Ingle (address unknown)
   9  *
  10  * $Log$
  11  * Revision 1.1  1998/09/28 08:08:38  robertj
  12  * Initial revision
  13  *
  14  */
  15
  16 #define WANTVXDWRAPS
  17
  18 #include <basedef.h>
  19 #include <vmm.h>
  20 #include <vxdwraps.h>               // must come last
  21
  22 #include "lock.h"
  23
  24
  25 #pragma VxD_LOCKED_CODE_SEG
  26 #pragma VxD_LOCKED_DATA_SEG
  27
  28
  29 DWORD _stdcall PacketPageLock(DWORD lpMem, DWORD cbSize)
  30 {
  31   // lock a page
  32
  33   DWORD LinOffset = lpMem & 0xfff; // page offset of memory to map
  34   DWORD LinPageNum = lpMem >> 12;  // generate page number
  35   DWORD nPages = ((lpMem + cbSize) >> 12) - LinPageNum + 1; // Calculate # of pages to map globally
  36
  37   // Return global mapping of passed in pointer, as this new pointer
  38   // is how the memory must be accessed out of context.
  39   return _LinPageLock(LinPageNum, nPages, PAGEMAPGLOBAL) + LinOffset;
  40 }
  41
  42
  43 void _stdcall PacketPageUnlock(void * lpMem, DWORD cbSize)
  44 {
  45   // unlock a page
  46
  47   DWORD LinPageNum = (DWORD)lpMem >> 12;
  48   DWORD nPages = (((DWORD)lpMem + cbSize) >> 12) - LinPageNum + 1;
  49
  50   // Free globally mapped memory
  51   _LinPageUnlock(LinPageNum, nPages, PAGEMAPGLOBAL);
  52 }
  53
  54
  55 // End of File ////////////////////////////////////////////////////////////////