Date: Mon, 11 Jan 93 15:38:18 EST
From: DJ Delorie <dj AT ctron DOT ctron DOT com>
To: S0R1282%tamzeus DOT bitnet AT nic DOT near DOT net
Cc: djgpp AT sun DOT soe DOT clarkson DOT edu
Subject: help w/ BIOS timer tick

#define MK_FP(s,o) (0xE0000000 + s*16 + o)

Use this for accessing BIOS memory.  Otherwise, you will be reading
your own address space, which starts at virtual address 0.  To protect
from NULL references, addresses 0x000 - 0xfff are unmapped and give a
fault when you access them.  Your code begins at 0x1000, and data
begins at 0x400000.  Stack grows down from 0x7fffffff.  Physical
memory is mapped starting at 0xe0000000.  Read the README and FAQ.

DJ