>> PIC:   Set bit, NOP, Clear bit
>> AVR:  Read I/O, Or bit high, Output, Read I/O, And bit low, Output.
>
>PIC:    bsf     PORTB,4
>        nop
>        bcf     PORTB,4         ; -> 800ns pulse on scope (10MHz)
>
>
>AVR:    sbi     PORTB,PB4
>        nop
>        cbi     PORTB,PB4       ; -> 300ns pulse on scope (10MHz)

Sorry, I forgot, I haven't played with that code in a while.

>
>BTW, the PIC function destroyed the output latch of input pins (most of us
>stumbled on this when first doing I2C).
>
>The AVR function didn't.
>
>Any questions?


I didn't need any NOP on the AVR parts, I can bit-twiddle as fast as I like
without problems.  The PIC didn't always output properly when I didn't use
the NOP.  In both cases, I didn't care about that bit's previous state, I
was
explicitly sending bit sequences in straightline code.

Without the NOP, (which isn't needed in the AVR) it's 4X faster at raw bit
I/O at any given clock.