Post by thread:test accumulator for zero

At 09:15 PM 1/5/97 -0500, Brad Pousland wrote: >What is the best way to test if the accumulator is zero? add zero then check zero flag, is that one way of doing that? I actually learned that at a Microchip seminar. If that's wrong, then I didn't learn that at a Microchip seminar. craig

> What is the best way to test if the accumulator is zero? If you have not just done an instruction which sets the Z flag (in which case testing the Z flag will give you the answer) your best bet is most likely "IORLW 0" followed by testing the Z flag. If you have a spare RAM location and specifically desire not to affect the Z flag, you could use three instructions thus: movwf SPARE incfsz SPARE decfsz SPARE do_something If do_something is executed, then the accumulator was not zero. Note that the incfsz instruction was chosen because it performs an increment without affecting any flags.

> >What is the best way to test if the accumulator is zero? > > add zero then check zero flag, is that one way of doing that? That works, but it clears the carry flag. If you want the carry flag cleared, that's fine, otherwise it's not so great. Normally I would use IORLW 0; that leaves carry alone.

>> >What is the best way to test if the accumulator is zero? >> >> add zero then check zero flag, is that one way of doing that? > >That works, but it clears the carry flag. If you want the carry flag >cleared, that's fine, otherwise it's not so great. Normally I would use >IORLW 0; that leaves carry alone. AND it has the advantage of working in both the 12 and 14 bit PICs. myke "There are only three kinds of economists in the world. Those who can count and those who can't." - Eddy George, governor of the Bank of England

part 0 644 bytes ---------- De: Brad Pousland[SMTP:spam_OUTbpouslanTakeThisOuTMOLE.UVM.EDU] Enviado: domingo 5 de enero de 1997 23:15 Para: Multiple recipients of list PICLIST Asunto: test accumulator for zero What is the best way to test if the accumulator is zero? Respectfully, Brad ---------------------------- Thanks for all - Mil gracias ---------------------------- Eduardo Jorge Mart’nez VŽlez a Asesoria & & s Sistematizacion INET: .....ejmvKILLspam@spam@satlink.com 73070.3653KILLspamcompuserve.com CServe: 73070,3653 2000-Rosario-SF-Argentina TelFax: (54)(41)254561 Tel: (54)(41)8804 ----------------------------