Information about BIOS and the boot process

Ivan Gustavo ivan at munix.com.br
Fri Mar 28 11:10:01 CET 2003


ron minnich wrote:

 >On Fri, 28 Mar 2003, SONE Takeshi wrote:
 >
 >
 >
 >>CPU starts with last 16 byte of address space.
 >>On a 386 or later it's FFFFFFF:0000??
 >>
 >>
 >
 >CPU starts out in "big real mode" at 0xffff0000,
 >

Tanks :)

But, other ask... Ok , the CS point to the last accessible segment, and
IP to the  last addess less  16 bytes...
What I do not understand is, how the bios data go to there  (may be
funny to you, so I dont find nothing documentation about)...
I ask it because a common bios have 256k and the segment which the
processor point is  752Kbytes far...
... so I guess I am not imagining right.


 >and most BIOSes (linuxbios too) do a jump cs:ip to 0xf000:0x0, which 
pops the CPU into the
 >old 8086 real mode.
 >
 >kron
 >
 >
 >
 >
 >


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Ivan Gustavo Munix dos Santos
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