Hi Peter and Rudolf. Thanks for the answers and tips. They are realy helpfull ! I'll take a look.
Rafael R. Machado
Em Sáb, 9 de jan de 2016 17:19, Rudolf Marek r.marek@assembler.cz escreveu:
Hi,
I guess your question is more general than the coreboot related right?
If you have a firmware image dump of the flash (not the file you download from board vendor) then yes, first location to be executed is the instruction located 16 bytes before end of the image.
In coreboot see in build/ bootblock_inc.S which also has reset16.inc and entry16.inc which is a real start. Consult the Intel or AMD manual to see the CPU state after reset. The CPU starts in real mode, but CS base is shifted to last 64KB before end of 4GB address space. In general your CPU starts in compatible mode with 8086 manufactured in 1978.
Thanks Rudolf