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minor hash_fn() followups

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- remove an odd space
  - "rounds" is fine, but "bits" is more precise
  - after fixing a typo, four parallel hashes no
    longer was any faster (or slower) than three,
    so I consider that TODO now done

Change-Id: I7fff29640c1238229418bd8385b3b3aeae4ad68f
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/338621
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>
This commit is contained in:
Mike Klein 2020-11-25 09:35:09 -06:00 committed by Skia Commit-Bot
parent 56b1b80795
commit 6e5079a280
1 changed files with 2 additions and 3 deletions
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5
src/opts/SkChecksum_opts.h
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@ -18,7 +18,7 @@
#if 1 && SK_CPU_SSE_LEVEL >= SK_CPU_SSE_LEVEL_SSE42
#include <immintrin.h>
static uint32_t crc32c_1(uint32_t seed, uint8_t v) { return _mm_crc32_u8 (seed, v); }
static uint32_t crc32c_1(uint32_t seed, uint8_t v) { return _mm_crc32_u8(seed, v); }
static uint32_t crc32c_8(uint32_t seed, uint64_t v) {
#if 1 && (defined(__x86_64__) || defined(_M_X64))
return _mm_crc32_u64(seed, v);
@ -39,7 +39,7 @@
std::array<uint32_t, 256> t;
for (int i = 0; i < 256; i++) {
t[i] = i;
for (int rounds = 8; rounds --> 0; ) {
for (int bits = 8; bits --> 0; ) {
t[i] = (t[i] & 1) ? (t[i] >> 1) ^ 0x82f63b78
: (t[i] >> 1);
}
@ -104,7 +104,6 @@ namespace SK_OPTS_NS {
// Handle the bulk with a few data-parallel independent hashes,
// taking advantage of pipelining and superscalar execution.
// TODO: four parallel hashes looks faster than three?
if (len >= 24) {
uint32_t a = seed,
b = seed,