msdos/int11.c

   1 /*
   2  * BIOS interrupt 11h handler
   3  */
   4
   5 #include <stdio.h>
   6 #include <stdlib.h>
   7 #include "miscemu.h"
   8 #include "msdos.h"
   9 #include "drive.h"
  10 #include "stddebug.h"
  11 #include "debug.h"
  12
  13 /**********************************************************************
  14  *          INT_Int11Handler
  15  *
  16  * Handler for int 11h (get equipment list).
  17  */
  18 void WINAPI INT_Int11Handler( CONTEXT *context )
  19 {
  20     int diskdrives = 0;
  21     int parallelports = 0;
  22     int serialports = 0;
  23     int x;
  24
  25 /* borrowed from Ralph Brown's interrupt lists
  26
  27                     bits 15-14: number of parallel devices
  28                     bit     13: [Conv] Internal modem
  29                     bit     12: reserved
  30                     bits 11- 9: number of serial devices
  31                     bit      8: reserved
  32                     bits  7- 6: number of diskette drives minus one
  33                     bits  5- 4: Initial video mode:
  34                                     00b = EGA,VGA,PGA
  35                                     01b = 40 x 25 color
  36                                     10b = 80 x 25 color
  37                                     11b = 80 x 25 mono
  38                     bit      3: reserved
  39                     bit      2: [PS] =1 if pointing device
  40                                 [non-PS] reserved
  41                     bit      1: =1 if math co-processor
  42                     bit      0: =1 if diskette available for boot
  43 */
  44 /*  Currently the only of these bits correctly set are:
  45                 bits 15-14              } Added by William Owen Smith,
  46                 bits 11-9               } wos@dcs.warwick.ac.uk
  47                 bits 7-6
  48                 bit  2                  (always set)
  49 */
  50
  51     if (DRIVE_IsValid(0)) diskdrives++;
  52     if (DRIVE_IsValid(1)) diskdrives++;
  53     if (diskdrives) diskdrives--;
  54
  55     for (x=0; x!=MAX_PORTS; x++)
  56     {
  57         if (COM[x].devicename)
  58             serialports++;
  59         if (LPT[x].devicename)
  60             parallelports++;
  61     }
  62     if (serialports > 7)                /* 3 bits -- maximum value = 7 */
  63         serialports=7;
  64     if (parallelports > 3)              /* 2 bits -- maximum value = 3 */
  65         parallelports=3;
  66
  67     AX_reg(context) = (diskdrives << 6) | (serialports << 9) |
  68                       (parallelports << 14) | 0x02;
  69 }