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Back out he XOR swap trick, it is slower than a temp variable on

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modern CPUs.
This commit is contained in:
Todd C. Miller
2007-08-24 00:28:57 +00:00
parent eb4b7b2e6b
commit b63a4c9db0
1 changed files with 3 additions and 4 deletions
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7
parse.h
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@@ -146,13 +146,12 @@ struct defaults {
/* /*
* Append one queue (or single entry) to another using the * Append one queue (or single entry) to another using the
* circular properties of the prev pointer to simplify the logic. * circular properties of the prev pointer to simplify the logic.
* We use XOR to swap the two prev pointers to avoid a temp variable.
*/ */
#define LIST_APPEND(h, e) do { \ #define LIST_APPEND(h, e) do { \
void *_tail = (e)->prev; \
(h)->prev->next = (e); \ (h)->prev->next = (e); \
(long)(e)->prev ^= (long)(h)->prev; \ (e)->prev = (h)->prev; \
(long)(h)->prev ^= (long)(e)->prev; \ (h)->prev = _tail; \
(long)(e)->prev ^= (long)(h)->prev; \
} while (0) } while (0)
/* /*