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buflib: optimize find_block_before

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Exiting the loop implies next_block == block, so remove that check.
The check ret < block is false only if block is the first block, which
can be checked before the loop, saving a few cycles in that case.

Change-Id: Id493b5259a23a35a70b09dfe4bc4eacaf420760c
This commit is contained in:
Aidan MacDonald 2022-03-28 21:23:39 +01:00
parent 6beebd75e7
commit bcaa9465e9
1 changed files with 10 additions and 11 deletions
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21
firmware/buflib.c
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@ -664,23 +664,22 @@ find_block_before(struct buflib_context *ctx, union buflib_data* block,
union buflib_data *ret = ctx->buf_start,
*next_block = ret;
/* no previous block */
if (next_block == block)
return NULL;
/* find the block that's before the current one */
while (next_block < block)
while (next_block != block)
{
ret = next_block;
next_block += abs(ret->val);
}
/* If next_block == block, the above loop didn't go anywhere. If it did,
* and the block before this one is empty, that is the wanted one
*/
if (next_block == block && ret < block)
{
if (is_free && ret->val >= 0) /* NULL if found block isn't free */
return NULL;
return ret;
}
return NULL;
/* don't return it if the found block isn't free */
if (is_free && ret->val >= 0)
return NULL;
return ret;
}
/* Free the buffer associated with handle_num. */