On Sat, 2 Jan 1999, Riley Williams wrote:
[snip]
> Not quite: It's actually at real-mode segment address -1:0 which
> corresponds to address 000FFFF0 hex in the real-mode memory map...
[snip]
I don't know about the pentium, but this isn't what the 386 programmer's
manual says. the important paragraph is included below...
andru
10.2.3 First Instructions
After RESET, address lines A{31-20} are automatically asserted for
instruction fetches. This fact, together with the initial values of CS:IP,
causes instruction execution to begin at physical address FFFFFFF0H. Near
(intrasegment) forms of control transfer instructions may be used to pass
control to other addresses in the upper 64K bytes of the address space.
The first far (intersegment) JMP or CALL instruction causes A{31-20} to
drop low, and the 80386 continues executing instructions in the lower one
megabyte of physical memory. This automatic assertion of address lines
A{31-20} allows systems designers to use a ROM at the high end of the
address space to initialize the system.
