Messages in this thread | | | Date | Thu, 7 Jan 2010 22:18:55 +0100 | Subject | Re: [PATCH] lib/vsprintf.c: Add %pMF to format FDDI bit reversed MAC addresses | From | Michał Mirosław <> |
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2010/1/7 Joe Perches <joe@perches.com>: [...] > diff --git a/lib/vsprintf.c b/lib/vsprintf.c > index d4996cf..36959cc 100644 > --- a/lib/vsprintf.c > +++ b/lib/vsprintf.c > @@ -25,6 +25,7 @@ > #include <linux/kallsyms.h> > #include <linux/uaccess.h> > #include <linux/ioport.h> > +#include <linux/bitrev.h> > #include <net/addrconf.h> > > #include <asm/page.h> /* for PAGE_SIZE */ > @@ -675,17 +676,37 @@ static char *resource_string(char *buf, char *end, struct resource *res, > return string(buf, end, sym, spec); > } > > +static u8 mac_byte(u8 val) > +{ > + return val; > +} > + > +static u8 mac_byte_rev(u8 val) > +{ > + return bitrev8(val); > +} > + > static char *mac_address_string(char *buf, char *end, u8 *addr, > struct printf_spec spec, const char *fmt) > { > char mac_addr[sizeof("xx:xx:xx:xx:xx:xx")]; > char *p = mac_addr; > int i; > + u8 (*mac_byte_fn)(u8 val); > + char separator; > + > + if (fmt[1] == 'F') { /* FDDI canonical format */ > + mac_byte_fn = mac_byte_rev; > + separator = '-'; > + } else { > + mac_byte_fn = mac_byte; > + separator = ':'; > + } > > for (i = 0; i < 6; i++) { > - p = pack_hex_byte(p, addr[i]); > + p = pack_hex_byte(p, mac_byte_fn(addr[i])); > if (fmt[0] == 'M' && i != 5) > - *p++ = ':'; > + *p++ = separator; > } > *p = '\0'; > [...]
Something like the following might be smaller and faster - no functions and their calls (just an idea);
int rev = (fmt[1] == 'F'); ... p = pack_hex_byte(p, rev ? bitrev8(addr[i]) : addr[i]);
Best Regards, Michał Mirosław -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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