Hello,

I would want know if I am forced to use only the 8086's instructions in real mode, because I am trying to write a little kernel (real mode) that checks if the CPU has the SSE4 set, using CPUID (that is not in the 8086 set) instruction.

Regards.

NO

Today 8086 cpu is rare, anyway you can write code that checks the processor type..

* FROM INTEL *

Check for 8086:
Bits 12-15 of the FLAGS register are always set on the 8086 processor

Check for 286:
Bits 12-15 of the FLAGS register are always clear on the
286 processor in real-address mode.

Check for 386 processor:
The AC bit, bit #18, is a new bit introduced in the EFLAGS
register on the Intel486 processor to generate alignment faults.
This bit cannot be set on the Intel386 processor.


Check for 486 processor:
Checking for ability to set/clear ID flag (Bit 21) in EFLAGS
which indicates the presence of a processor with the CPUID instruction.

Have Fun

Ok, thanks for these informations DJ Mauretto