Subversion Repositories SvarDOS

Rev

Rev 54 | Details | Compare with Previous | Last modification | View Log | RSS feed

Rev Author Line No. Line
54 mv_fox 1 
/*
2 
 * CD-ROM detection routines
3 
 * Copyright (C) 2016 Mateusz Viste
4 
 */
5 
 
6 
#include <dos.h>
7 
#include "cdrom.h" /* include self for control */
8 
 
9 
/* returns 1 if drive drv is a valid CDROM, zero if not, negative if no MSCDEX (0=A:, etc) */
10 
int cdrom_drivecheck(int drv) {
11 
  union REGS r;
12 
  r.x.ax = 0x150B;
13 
  r.x.cx = drv;
14 
  int86(0x2F, &r, &r);
15 
  if (r.x.bx != 0xADAD) return(-1); /* look for the MSCDEX signature */
16 
  if (r.x.ax == 0) return(0);
17 
  return(1);
18 
}
19 
 
20 
/* returns the identifier of the first CDROM drive (0=A:, etc), or a negative value on error */
21 
int cdrom_findfirst(void) {
22 
  int i;
23 
  for (i = 2; i < 26; i++) { /* check drives from C to Z */
24 
    int cdres = cdrom_drivecheck(i);
25 
    if (cdres == 0) continue;
26 
    if (cdres == 1) return(i);
27 
    break;
28 
  }
29 
  return(-1);
30 
}