msdos/int25.c

   1 /*
   2  * DOS interrupt 25h handler
   3  */
   4
   5 #include <stdlib.h>
   6 #include <string.h>
   7 #include <fcntl.h>
   8 #include <unistd.h>
   9 #include "msdos.h"
  10 #include "miscemu.h"
  11 #include "drive.h"
  12 #include "debugtools.h"
  13
  14 DEFAULT_DEBUG_CHANNEL(int);
  15
  16
  17 /**********************************************************************
  18  *          INT_Int25Handler (WPROCS.137)
  19  *
  20  * Handler for int 25h (absolute disk read).
  21  */
  22 void WINAPI INT_Int25Handler( CONTEXT86 *context )
  23 {
  24     BYTE *dataptr = CTX_SEG_OFF_TO_LIN( context, context->SegDs, context->Ebx );
  25     DWORD begin, length;
  26
  27     if (!DRIVE_IsValid(LOBYTE(context->Eax)))
  28     {
  29         SET_CFLAG(context);
  30         AX_reg(context) = 0x0201;        /* unknown unit */
  31         return;
  32     }
  33
  34     if (LOWORD(context->Ecx) == 0xffff)
  35     {
  36         begin   = *(DWORD *)dataptr;
  37         length  = *(WORD *)(dataptr + 4);
  38         dataptr = (BYTE *)CTX_SEG_OFF_TO_LIN( context,
  39                                         *(WORD *)(dataptr + 8), *(DWORD *)(dataptr + 6) );
  40     }
  41     else
  42     {
  43         begin  = LOWORD(context->Edx);
  44         length = LOWORD(context->Ecx);
  45     }
  46     TRACE("int25: abs diskread, drive %d, sector %ld, "
  47                  "count %ld, buffer %p\n",
  48           LOBYTE(context->Eax), begin, length, dataptr);
  49
  50     DRIVE_RawRead(LOBYTE(context->Eax), begin, length, dataptr, TRUE);
  51     RESET_CFLAG(context);
  52 }
  53