Niki Denev wrote this message on Sat, Aug 12, 2006 at 11:42 +0300:
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> John Baldwin wrote:
> > On Saturday 05 August 2006 10:06, Niki Denev wrote:
> >> for(i=0; i < sizeof(config_table_t); i++) {
> >> r = bus_space_read_1(sc->bar.tag, sc->bar.hdl, i);
> >> *((u_int8_t *)&sc->cfg_table + i) = r;
> >> }
> >
> > Note that you can replace this with:
> >
> > bus_space_read_multi_1(sc->bar.tag, sc->bar.hdl, 0,
> > (u_int8_t *)&sc->cfg_table, sizeof(config_table_t));
> >
>
> I can't understand why the code above gives me different results.
> i.e.:
>
> for(i=0; i < sizeof(config_table_t); i++) {
> *((u_int8_t *)&sc->cfg_table + i) = bus_read_1(sc->res, i);
> }
> printf("cfg_table signature : %08X\n", sc->cfg_table.signature);
>
> This prints : cfg_table signaature 0xEFEFFEFE, which is the correct signature
> that should be read from the card.
>
> But this code :
>
> bus_read_multi_1(sc->res, 0, (u_int8_t *)&sc->cfg_table,
> sizeof(config_table_t));
> printf("cfg_table signature : %08X\n", sc->cfg_table.signature);
>
> prints : cfg_table signature 0xFEFEFEFE
> which is not correct...
>
> Shouldn't the above examples do exactly the same thing?
No, read_multi reads from the same location every time.. This is for
things like a FIFO where the value can change each time, you want
bus_read_region_1... Read the bus_space(9) man page for more info
about the differences between the two...
http://www.freebsd.org/cgi/man.cgi?query=bus_space&apropos=0&sektion=0&manpath=FreeBSD+6.1-RELEASE&format=html
--
John-Mark Gurney Voice: +1 415 225 5579
"All that I will do, has been done, All that I have, has not."
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