ljmp 0xa000, 0x0000
this instruction will set the CS to 0xa000 and set the EIP 0x0000. Bascially, it will start to execute code at location CS*16 + EIP = 0xa0000
in real mode, if you write:
jmp 0xa0000, it won't work, it will have compile errors. because there is only 16 bits.
see first part is CS, second part is EIP
http://docs.sun.com/app/docs/doc/805-4693/6j4emccqq?l=ru&a=view
please also see wiki jmp instruction
http://en.wikipedia.org/wiki/JMP_%28x86_instruction%29
outb %al, (%dx)
outb %al, %dx
outb %al, 0x80
oub instruction only could out to value stores at dx, or immeidate values.
please see more inforamtion from
"Intel Architecture Software Developer's Manual, Volume 2: Instruction Set Reference Manual
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