[net.micro.pc] PC6300 PLUS ROM-BIOS Bug ?

vg55611@ihuxk.UUCP (gopal) (09/25/86)

I think I have found a bug in the AT&T 6300+ ROM-BIOS in the process of
trying to figure out why a certain piece of software that works on the
6300 and the IBM PC did not work my 6300+. When the software interrupt 13H
is called with AX=0, DL=A7 and SI=3C12, the processor hung up (apprently
lost program control). If SI is set to 0, however, everything works fine.
Since the SI value is not supposed to matter, this is not supposed to happen.
Using debug, I can re-create the error by assembling & executing this code:
XXXX:0100 mov ax,0
          mov dl,a7
          mov si,3c12
          int 13
Question is, can anyone else confirm my experience or offer any explanations ?
I have a 20M hard disk, ROM-BIOS Version 2.05A and use MS-DOS 3.1.
Thanks in advance.

Venu P. Gopal, ihnp4!ihuxk!vg55611