Date: Tue, 06 Jun 1995 07:11:12 -0700 From: David Greenman <davidg@Root.COM> To: Bruce Evans <bde@zeta.org.au> Cc: fenner@parc.xerox.com, freebsd-bugs@FreeBSD.org, gibbs@freefall.cdrom.com Subject: Re: FTP install is *almost* there... Message-ID: <199506061411.HAA00434@corbin.Root.COM> In-Reply-To: Your message of "Tue, 06 Jun 95 19:14:23 %2B1000." <199506060914.TAA00354@godzilla.zeta.org.au>
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>>>The driver sees (1 << irq_number), or 0 for none/unspecified/auto.
>
>> Gack, you're right. Userconfig has brokeness in this area. Specifying -1
>>will result in shifting the bit all the way off the end, resulting in "0".
>
>No, it handles -1 specially.
Ahh, I forgot that "irq" was unsigned...so the test:
parms[0].parm.dparm->id_irq = (irq < 16 ? 1 << irq : 0);
Treats irq as 0xffffffff, not -1, and thus ends up with 0.
>-1 is converted to 0 in mkioconf(). irq numbers are exponentiated more
>machine-independently by converting them to a string and prefixing "IRQ".
>isa.h somewhat confusingly defines IRQ0 as 0x0001 etc. I can't see where
>`?' and `none' are distinguished in config.y. lang.l converts `?' to -1
>which is the same as the default (`none') value. Anyway, the drivers
>apparently get it right by always dealing with the mask. -1 isn't a
>valid mask and drivers apparently don't set id_irq to it.
Huh? How could drivers deal with anything other than the mask? ...anyway,
you appear to be correct - '?' gets converted to 0 before it is output to
ioconf.c.
So this brings us full circle and I'm not sure what we've accomplished by
this exercise. :-) ...other than my test in if_ed.c for the irq should be
changed to irq == 0 rather than irq <= 0.
-DG
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