On Sun, Dec 3, 2017, at 11:36 AM, Gene Heskett wrote:
> On Sunday 03 December 2017 11:04:22 andy pugh wrote:
>
> > On 3 December 2017 at 16:00, Gene Heskett <ghesk...@shentel.net> wrote:
> > > I find my self having to pick up and move a net statement in order
> > > to satisfy the requirement that the src statement must be the first
> > > encountered as the file is being parsed,
> >
> > There is no such requirement. You can connect the input and output
> > pins to a net in absolutely any order you like.
>
> You are saying that
>
> net netname output.pinname another-output.pinname input.pinname is legal
> now? IOW hal now knows what is a source and what is a load
> automatically, and will use the first output.pinname it finds in a long
> line of names as the source pin for that netname?
What do you mean by "source pin"?
When halcmd is making a connection, it absolutely does not care
whether a signal has a source. Here is what "net" does, in pseudo-code:
if ( signal does not exist ) {
// need to create signal
if ( first pin does not exist ) {
ERROR
}
create signal using type of first pin
}
// signal exists now
for (every pin listed) {
if ( pin does not exist ) {
ERROR
}
if ( {pin type does not match signal type ) {
ERROR
}
if (( pin is an output) AND (signal already has an output pin)) {
ERROR
}
connect pin to signal
}
"type" above means things like bit, float, s32, etc
The net command won't let two outputs drive the same net.
That is done by the last conditional in the pseudo-code above.
But nothing about that code cares which order you connect the
pins.
>
> Okkaaayyyy. But wasn't that a requirement previous to "two-pass"?
two-pass has absolutely nothing to do with net commands. The only
thing two-pass processes in the first pass are loadrt commands.
See http://linuxcnc.org/docs/html/hal/twopass.html
> Knowing that now, it will ease my mind considerably because it means I
> can use a "netname new-target" high in a file that is not developed as a
> source signal until much later in the file.
That has always been true.
>
> Thanks Andy.
>
> Cheers, Gene Heskett
> --
> "There are four boxes to be used in defense of liberty:
> soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author)
> Genes Web page <http://geneslinuxbox.net:6309/gene>
>
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