msdos/int26.c

   1 /*
   2  * DOS interrupt 26h handler
   3  */
   4
   5 #include <stdlib.h>
   6 #include <fcntl.h>
   7 #include <unistd.h>
   8 #include "msdos.h"
   9 #include "ldt.h"
  10 #include "miscemu.h"
  11 #include "drive.h"
  12 #include "debug.h"
  13
  14 /**********************************************************************
  15  *          INT_Int26Handler
  16  *
  17  * Handler for int 26h (absolute disk read).
  18  */
  19 void WINAPI INT_Int26Handler( CONTEXT *context )
  20 {
  21     BYTE *dataptr = CTX_SEG_OFF_TO_LIN( context, DS_reg(context), EBX_reg(context) );
  22     DWORD begin, length;
  23     int fd;
  24
  25     if (!DRIVE_IsValid(AL_reg(context)))
  26     {
  27         SET_CFLAG(context);
  28         AX_reg(context) = 0x0101;        /* unknown unit */
  29         return;
  30     }
  31
  32     if (CX_reg(context) == 0xffff)
  33     {
  34         begin   = *(DWORD *)dataptr;
  35         length  = *(WORD *)(dataptr + 4);
  36         dataptr = (BYTE *)CTX_SEG_OFF_TO_LIN( context,
  37                                         *(WORD *)(dataptr + 8), *(DWORD *)(dataptr + 6) );
  38     }
  39     else
  40     {
  41         begin  = DX_reg(context);
  42         length = CX_reg(context);
  43     }
  44
  45     TRACE(int,"int26: abs diskwrite, drive %d, sector %ld, "
  46                  "count %ld, buffer %d\n",
  47                  AL_reg(context), begin, length, (int) dataptr );
  48
  49     if ((fd = DRIVE_OpenDevice( AL_reg(context), O_WRONLY )) != -1)
  50     {
  51         lseek( fd, begin * 512, SEEK_SET );
  52         /* FIXME: check errors */
  53         write( fd, dataptr, length * 512 );
  54         close( fd );
  55     }
  56
  57     RESET_CFLAG(context);
  58 }