Date: Sun, 28 Dec 1997 14:42:55 +1100 From: Bruce Evans <bde@zeta.org.au> To: bde@zeta.org.au, grog@lemis.com Cc: freebsd-current@FreeBSD.ORG, skynyrd@opus.cts.cwu.edu Subject: Re: Remote gdb (was: no boot: config -g and options DDB) Message-ID: <199712280342.OAA04367@godzilla.zeta.org.au>
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>>> Yes, but fwrite() doesn't go on and talk to the device registers. ddb >> >> Sure it does, if the output stream is a device. > >No, it calls write(2) to do it for it. Of course. Actually, it calls __sfvwrite() in FreeBSD, and write(2) makes some far call, and the device driver about 5 layers below talks to the device registers. >>> ddb doesn't use the device driver. It talks directly to the device >>> with functions like: >>> >>> void >>> siocnputc(dev, c) >> >> These functions are part of the device driver. > >OK, but they're only *part* of the device driver, and ddb calls them >directly without first setting the control registers. Of course. Some layer in the driver sets them. Bruce
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