Subject: Re: bus.h style question
To: Martin Husemann <firstname.lastname@example.org>
From: Matt Thomas <email@example.com>
Date: 08/14/1997 12:48:19
At 07:05 AM 8/14/97 +0200, Martin Husemann wrote:
>I have two question on usage of the bus.h interface:
>My card is mapped into ISA memory. At one time it generates a zero terminated
>string in this memory area, followed by a u_int32_t value. So what I do is:
> int i;
> u_int32_t value;
> u_int8_t *p, buffer[MAX_BUF_SIZE];
> for (p = buffer, i = 0; *p && i < sizeof buffer; i++, p++)
> *p++ = bus_space_read_1(sc->sc_iot, sc->sc_ioh, MYOFF+i);
That can't be right. buffer is not initialized yet.
u_int8_t *p, buffer[MAX_BUF_SIZE];
*p = bus_space_read_1(sc->sc_iot, sc->sc_ioh, MYOFF);
for (p = buffer, i = 0; *p && i < sizeof buffer - 1; i++)
*++p = bus_space_read_1(sc->sc_iot, sc->sc_ioh, MYOFF + (i+1));
>Could I use bus_space_read_4 savely to get value? Are there alignement
>constraints in the bus.h interface?
I've wondered that as well. My guess would have to be yes.
>The other question is the expected byte order. At another point I do check
>a signature with:
>On the i386 the signature I get is 0x4447 - should I expect 0x4744 on
>the atari or amiga? I guess (hope?) not.
I would hope the bus_space_ calls would byteswap >1 byte units as
appropriate for the bus. (especially since they're are no
big endian byteswap routines).
Matt Thomas Internet: firstname.lastname@example.org
3am Software Foundry WWW URL: http://www.3am-software.com/bio/matt.html
Nashua, NH Disclaimer: I disavow all knowledge of this message