Date: Tue, 24 Mar 1998 21:36:34 -0600 From: Jonathan Lemon <jlemon@americantv.com> To: Michael Searle <searle@longacre.demon.co.uk> Cc: freebsd-questions@FreeBSD.ORG Subject: Re: use of /dev/io Message-ID: <19980324213633.43955@right.PCS> In-Reply-To: <m2C127B69@longacre.demon.co.uk>; from Michael Searle on Mar 03, 1998 at 11:22:20PM %2B0000 References: <m2C127B69@longacre.demon.co.uk>
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On Mar 03, 1998 at 11:22:20PM +0000, Michael Searle wrote: > I'm having problems doing direct IO with /dev/io - AFAIK, you just open this > device to change the memory permissions to allow access to IO addresses. > But I just get a segv, although the open succeeds. (I think the IO addresses > may have been remapped, as this port address is from DOS and man mem says > this has been done for the ISA space.) This is my code: The IO address space is separate from the memory address space, and is accessed with the inb/outb instructions. In your code, you are attempting to read memory location 0x3da; you should use something like inb(x03da). (where inb is the appropriate asm insn.) -- Jonathan To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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