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