Steven Rostedt writes:
> Thanks to Paul Mackennas for pointing out the mistakes of my original
Mackerras
> +static int test_24bit_addr(unsigned long ip, unsigned long addr)
> +{
> + long diff;
> +
> + /*
> + * Can we get to addr from ip in 24 bits?
> + * (26 really, since we mulitply by 4 for 4 byte alignment)
> + */
> + diff = addr - ip;
> +
> + /*
> + * Return true if diff is less than 1 << 25
> + * and greater than -1 << 26.
> + */
> + return (diff < (1 << 25)) && (diff > (-1 << 26));
I think this still isn't right, and the comment is one of those ones
that is only useful to people who can't read C, as it's just a
transliteration of the code.
The comment should say something like "Return true if diff can be
represented as a 26-bit twos-complement binary number" and the second
part of the test should be (diff >= (-1 << 25)). However, since you
define a test_offset() function in patch 4/5 that does the same test
but using only one comparison instead of two, why don't you just say:
return !test_offset(diff);
(having first moved test_offset() before test_24bit_addr)?
Paul.
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