[U-Boot] [PATCH v3 1/5] CONFIG_SYS_[ID]CACHE_OFF: unify the 'any' case
Tom Rini
trini at konsulko.com
Sun May 19 20:44:22 UTC 2019
On Fri, May 03, 2019 at 09:40:56AM -0400, Trevor Woerner wrote:
> According to De Morgan's Law[1]:
> !(A && B) = !A || !B
> !(A || B) = !A && !B
>
> There are 5 places in the code where we find:
> #if !(defined(CONFIG_SYS_ICACHE_OFF) && defined(CONFIG_SYS_DCACHE_OFF))
> and 4 places in the code where we find:
> #if (!defined(CONFIG_SYS_ICACHE_OFF) || !defined(CONFIG_SYS_DCACHE_OFF))
>
> In words, the construct:
> !defined(CONFIG_SYS_[DI]CACHE_OFF)
> means:
> "is the [DI]CACHE on?"
> and the construct:
> defined(CONFIG_SYS_[DI]CACHE_OFF)
> means:
> "is the [DI]CACHE off?"
>
> Therefore
> !(defined(CONFIG_SYS_ICACHE_OFF) && defined(CONFIG_SYS_DCACHE_OFF))
> means:
> "the opposite of 'are they both off?'"
> in other words:
> "are either or both on?"
> and:
> (!defined(CONFIG_SYS_ICACHE_OFF) || !defined(CONFIG_SYS_DCACHE_OFF)
> means:
> "are either or both on?"
>
> As a result, I've converted the 4 instances of '(!A || !B)' to '!(A && B)' for
> consistency.
>
> [1] https://en.wikipedia.org/wiki/De_Morgan%27s_laws
>
> Signed-off-by: Trevor Woerner <trevor at toganlabs.com>
Applied to u-boot/master, thanks!
--
Tom
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 819 bytes
Desc: not available
URL: <http://lists.denx.de/pipermail/u-boot/attachments/20190519/f3cb3005/attachment.sig>
More information about the U-Boot
mailing list