msdos/int26.c

   1 /*
   2  * DOS interrupt 26h handler
   3  */
   4
   5 #include <stdio.h>
   6 #include <stdlib.h>
   7 #include "msdos.h"
   8 #include "ldt.h"
   9 #include "miscemu.h"
  10 #include "drive.h"
  11 #include "stddebug.h"
  12 /* #define DEBUG_INT */
  13 #include "debug.h"
  14
  15 /**********************************************************************
  16  *          INT_Int26Handler
  17  *
  18  * Handler for int 26h (absolute disk read).
  19  */
  20 void INT_Int26Handler( CONTEXT *context )
  21 {
  22     BYTE *dataptr = PTR_SEG_OFF_TO_LIN( DS_reg(context), BX_reg(context) );
  23     DWORD begin, length;
  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 *)PTR_SEG_TO_LIN( *(SEGPTR *)(dataptr + 6) );
  37     }
  38     else
  39     {
  40         begin  = DX_reg(context);
  41         length = CX_reg(context);
  42     }
  43
  44     dprintf_int( stdnimp,"int26: abs diskwrite, drive %d, sector %ld, "
  45                  "count %ld, buffer %d\n",
  46                  AL_reg(context), begin, length, (int) dataptr );
  47
  48     RESET_CFLAG(context);
  49 }