| 0,0 → 1,30 |
|---|
| /* |
| * CD-ROM detection routines |
| * Copyright (C) 2016 Mateusz Viste |
| */ |
| |
| #include <dos.h> |
| #include "cdrom.h" /* include self for control */ |
| |
| /* returns 1 if drive drv is a valid CDROM, zero if not, negative if no MSCDEX (0=A:, etc) */ |
| int cdrom_drivecheck(int drv) { |
| union REGS r; |
| r.x.ax = 0x150B; |
| r.x.cx = drv; |
| int86(0x2F, &r, &r); |
| if (r.x.bx != 0xADAD) return(-1); /* look for the MSCDEX signature */ |
| if (r.x.ax == 0) return(0); |
| return(1); |
| } |
| |
| /* returns the identifier of the first CDROM drive (0=A:, etc), or a negative value on error */ |
| int cdrom_findfirst(void) { |
| int i; |
| for (i = 2; i < 26; i++) { /* check drives from C to Z */ |
| int cdres = cdrom_drivecheck(i); |
| if (cdres == 0) continue; |
| if (cdres == 1) return(i); |
| break; |
| } |
| return(-1); |
| } |