Hi Aurel,
That is very similar to what Oxygen does now, but going directly to machine code bytes without using an assembly code layer.
You need to be familiar with how the Pentium works, and the coding patterns of turning instructions into opcodes and address operands. The Pentium is a complex beast, but you only need a small proportion of the instruction set for performing math and logical operations.
The simplest call you can perform is the ret instruction: 0xc3
string s=chr(0xc3)
sys a=strptr s
call a
print "ok"