Re: Why BIOS maps in range 0x000F0000-0x000FFFF ?

On Wed, 27 Feb 2008 06:33:00 -0800 (PST), Lalatendu Das
<spamtrap@xxxxxxxxxx> wrote:

Why BIOS is mapped to 0x000F0000-0x000FFFF address range.
I know it has to be within 1 MB but my doubt is why it is above
particular range(0x000F0000-0x000FFFF ) within 1 MB.
Is it simply a standard or it has some significance ?

2 reasons:

1) That's where the original IBM PC put it.

2) Because the 808x starts executing code at F000:FFF0 (IIFC) after a
reset.

3) All later x86s start executing code at the same effective location,
0x10 bytes before the end of the address range of memory. Therefore,
later systems map the bios rom to both locations.
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