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 "stddebug.h"
  14 /* #define DEBUG_INT */
  15 #include "debug.h"
  16
  17 /**********************************************************************
  18  *          INT_Int26Handler
  19  *
  20  * Handler for int 26h (absolute disk read).
  21  */
  22 void WINAPI INT_Int26Handler( CONTEXT *context )
  23 {
  24     BYTE *dataptr = PTR_SEG_OFF_TO_LIN( DS_reg(context), BX_reg(context) );
  25     DWORD begin, length;
  26     int fd;
  27
  28     if (!DRIVE_IsValid(AL_reg(context)))
  29     {
  30         SET_CFLAG(context);
  31         AX_reg(context) = 0x0101;        /* unknown unit */
  32         return;
  33     }
  34
  35     if (CX_reg(context) == 0xffff)
  36     {
  37         begin   = *(DWORD *)dataptr;
  38         length  = *(WORD *)(dataptr + 4);
  39         dataptr = (BYTE *)PTR_SEG_TO_LIN( *(SEGPTR *)(dataptr + 6) );
  40     }
  41     else
  42     {
  43         begin  = DX_reg(context);
  44         length = CX_reg(context);
  45     }
  46
  47     dprintf_int( stdnimp,"int26: abs diskwrite, drive %d, sector %ld, "
  48                  "count %ld, buffer %d\n",
  49                  AL_reg(context), begin, length, (int) dataptr );
  50
  51     if ((fd = DRIVE_OpenDevice( AL_reg(context), O_WRONLY )) != -1)
  52     {
  53         lseek( fd, begin * 512, SEEK_SET );
  54         /* FIXME: check errors */
  55         write( fd, dataptr, length * 512 );
  56         close( fd );
  57     }
  58
  59     RESET_CFLAG(context);
  60 }