Very Computer

How do read memory address in FFFF:0000 ?

i'm trying this code, but is returning error:

#include <stdio.h>
#include <stdlib.h>

unsigned long pega_b(void)
{
__asm__
("
  push %ebp
  push %esi

  movl 0xffff0000, %esi
  movl (%esi), %eax

  pop %esi
  pop %ebp
");

Quote:}

main()
{
  printf("Valor do Endereco: FFFF:0000 \n");
  printf("VALOR2: 0x%x \n",pega_b());

Quote:}

IA32 CPUs have a 32-bit (or possibly 36-bit) address space.  You need
to read up on how 32-bit protected mode operating systems access
memory, then think about and ask your question again.

You might be better served by asking a more general question, like
"How do I read from the BIOS's memory?"

--

"I woke up this morning and realized what the game needed: pirates,
pimps, and gay furries."  - Rich "Lowtax" Kyanka

 : How do read memory address in FFFF:0000 ?

No way. No such addresssing scheme in Linux.

You probably mean "memory corresponding to segment 0xffff offset 0 in
real mode"?

If so, it is 0xffff0 in physical address space.

I'll read it using

memfd = open("/dev/mem",O_READ);
lseek(memfd,0xffff0,0)
read(memfd,buffer,size)

Your code would obvoisly fail becouse it tries to read
0xffff0000 instead of 0x000ffff0, and not from physical memory,
but from virtual address space of your program.

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