Save some bytes in program memory

[Mike, K8LH]

I was too quick on the trigger... That last example should be;

    if((portb ^ 15) == 0)
      nop();

     if((portb ^ 15) == 0)
00E8  300F      MOVLW 0x0F
00E9  0606      XORWF gbl_portb, W
00EA  1D03      BTFSS STATUS,Z
00EB  28ED      GOTO    label13


       nop();
00EC  0000      NOP
00ED        label13

[Art]

This variation only uses four words, which is pretty much how you might code it in assembler;

You could load portb into the temp variable, rotate it four times left, and check the value is b11110000,
and it wouldn't matter what was happening on the high bits of portb.

[Mike, K8LH]

This variation only uses four words, which is pretty much how you might code it in assembler;

You could load portb into the temp variable, rotate it four times left, and check the value is b11110000, and it wouldn't matter what was happening on the high bits of portb.

Is there some advantage doing it that way, Art?

[Art]

Only if there was something else going on with the 4 high bits of portb,
Otherwise any input on the high bits breaks the condition of portb ^ 15 = 0. or am I mistaken there?

[Mike, K8LH]

You're correct. Sorry I misunderstood, Art...