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.