-----Messaggio originale-----
Da: Clyde Smith-Stubbs <clyde@HTSOFT.COM>
A: PICLIST@MITVMA.MIT.EDU <PICLIST@MITVMA.MIT.EDU>
Data: sabato 6 maggio 2000 3.35
Oggetto: Re: questions


>On Sat, May 06, 2000 at 02:02:58AM +0200, Massimiliano Dellisanti Vilardi
wrote:
>> - Is there a way to compile a c source where there are unsigned long
variable? How can I solve this problem? How can I use 32 bit integers? Can I
solve this problem with the new C18 compiler?
>
>Yes, get HI-TECH C. It supports all ANSI data types.
>

Is it possible to get an evaluation version? Does it work with PIC17C766 ?

>> - Is there another way to reset a bit? I mean is there a better C code
than this : PORTX &= (0xFF - mybit)  ??
>
>Like this:
>
>        PORTX &= ~mybit;
>
>This assumes that "mybit" is a byte-size thing, and you want to reset the
>corresponding bits. The ~ operator is a bitwise inversion. To reset a
single bit, use
>
>        PORTX &= ~(1 << bitno);
>
>A decent compiler will optimize this when bitno is a constant to a single
instruction.
>


...but what happens if some lines of PORTX are configured as Output? The
statement (PORTX &= something) means that PORTX must be read and then
written:
what happens when I read output lines?
I thought there was a way to access directly a bit: I guess this is possible
using assembly: isn't there a way to do it in C ?
Thank you for your answer.

Max