msdos/int26.c

   1 /*
   2  * DOS interrupt 26h handler
   3  */
   4
   5 #include <stdio.h>
   6 #include <stdlib.h>
   7 #include <fcntl.h>
   8 #include <unistd.h>
   9 #include "msdos.h"
  10 #include "ldt.h"
  11 #include "miscemu.h"
  12 #include "drive.h"
  13 #include "debug.h"
  14
  15 /**********************************************************************
  16  *          INT_Int26Handler
  17  *
  18  * Handler for int 26h (absolute disk read).
  19  */
  20 void WINAPI INT_Int26Handler( CONTEXT *context )
  21 {
  22     BYTE *dataptr = PTR_SEG_OFF_TO_LIN( DS_reg(context), BX_reg(context) );
  23     DWORD begin, length;
  24     int fd;
  25
  26     if (!DRIVE_IsValid(AL_reg(context)))
  27     {
  28         SET_CFLAG(context);
  29         AX_reg(context) = 0x0101;        /* unknown unit */
  30         return;
  31     }
  32
  33     if (CX_reg(context) == 0xffff)
  34     {
  35         begin   = *(DWORD *)dataptr;
  36         length  = *(WORD *)(dataptr + 4);
  37         dataptr = (BYTE *)PTR_SEG_TO_LIN( *(SEGPTR *)(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 }