Hi, Peter,

>if interrupts should be prevented a "CLR EA" do the same.
SWI would not be prevented by this instruction while others are done.

>Since no "Break Module" available on the 8051, it seems no SWI needed.
I do not know. 8051 has 5 interrupt vectors, 8052 does abut 14, but it
does not mean the additional sources are never needed on 8051.
So, SWI instruction might be useful too in some situations.

Hi, Andy Neil,

>But you are right: on the 8051, one can simply set the appropriate hardware
>flag to invoke an interrupt from software
Such possibility is commonly present on other architectures too, plus SWI.


Best regards,
Oleg