Arrange the two xor instructions according to the specified
paradigm, then the two xor instructions can be fused to execute
which can save one issue slot and one execution latency.
Change-Id: Ic64bcfe569b2468e4dc9c13d073d367cc81fd937
Signed-off-by: liuqinfei <lucas.liuqinfei@huawei.com>
- It should be fine to enable pmull always on Apple Silicon
- macOS 12+ is required for PMULL instruction.
- Changed the conditional macro to __APPLE__
- Rewritten dispatcher using sysctlbyname
- Use __USER_LABEL_PREFIX__
- Use __TEXT,__const as readonly section
- use ASM_DEF_RODATA macro
- fix func decl
Change-Id: I800593f21085d8187b480c8bb3ab2bd70c4a6974
Signed-off-by: Taiju Yamada <tyamada@bi.a.u-tokyo.ac.jp>
+ Utilise `pmull2` instruction in main loops of arm64 crc functions and
avoid the need for `dup` to align multiplicands.
+ Use just 1 ASIMD register to hold both 64b p4 constants,
appropriately aligned.
+ Interleave quadword `ldr` with `pmull{2}` to avoid unnecessary stalls
on existing LITTLE uarch (which can only issue these instructions every
other cycle).
+ Similarly interleave scalar instructions with ASIMD instructions to
increase likelihood of instruction level parallelism on a variety of
uarch.
+ Cut down on needless instructions in non-critical sections to help
performance for small buffers.
+ Extract common instruction sequences into inner macros and moved
them into shared header - crc_common_pmull.h
+ Use the same human readable register aliases and register allocation
in all 4 implementations, never refer to registers without using human
readable alias.
+ Use #defines rather than .req to allow use of same names across
several implementations
+ Reduce tail case size from 1024B to 64B
+ Phrased the `eor` instructions in the main loop to more clearly show
that we can rewrite pairs of `eor` instructions with a single `eor3`
instruction in the presence of Armv8.2-SHA (should probably be an option
in multibinary in future).
Change-Id: I3688193ea4ad88b53cf47e5bd9a7fd5c2b4401e1
Signed-off-by: Samuel Lee <samuel.lee@microsoft.com>
