memset: use neon-less impl, reformat other asm

This commit is contained in:
Michael Scire 2020-03-11 08:45:00 -07:00
parent e42d3a3abf
commit 6c52cc3e26
4 changed files with 401 additions and 358 deletions

View file

@ -13,18 +13,7 @@
#include "asmdefs.h" #include "asmdefs.h"
#define SAVE_FPU_REGISTERS #define DC_ZVA_THRESHOLD 512
#define SKIP_ZVA_CHECK
#ifdef SAVE_FPU_REGISTERS
#define SAVE_Q0 str q0, [sp, #-16]!
#define RESTORE_Q0 ldr q0, [sp], #16
#else
#define SAVE_Q0
#define RESTORE_Q0
#endif
#define RETURN RESTORE_Q0; ret; .p2align 4
#define dstin x0 #define dstin x0
#define val x1 #define val x1
@ -35,93 +24,147 @@
#define zva_val x5 #define zva_val x5
ENTRY (memset) ENTRY (memset)
SAVE_Q0
dup v0.16B, valw bfi valw, valw, 8, 8
bfi valw, valw, 16, 16
bfi val, val, 32, 32
add dstend, dstin, count add dstend, dstin, count
cmp count, 96 cmp count, 96
b.hi L(set_long) b.hi L(set_long)
cmp count, 16 cmp count, 16
b.hs L(set_medium) b.hs L(set_medium)
mov val, v0.D[0]
/* Set 0..15 bytes. */ /* Set 0..15 bytes. */
tbz count, 3, 1f tbz count, 3, 1f
str val, [dstin] str val, [dstin]
str val, [dstend, -8] str val, [dstend, -8]
RETURN ret
1: tbz count, 2, 2f 1: tbz count, 2, 2f
str valw, [dstin] str valw, [dstin]
str valw, [dstend, -4] str valw, [dstend, -4]
RETURN ret
2: cbz count, 3f 2: cbz count, 3f
strb valw, [dstin] strb valw, [dstin]
tbz count, 1, 3f tbz count, 1, 3f
strh valw, [dstend, -2] strh valw, [dstend, -2]
3: RETURN 3: ret
/* Set 17..96 bytes. */ /* Set 16..96 bytes. */
.p2align 4
L(set_medium): L(set_medium):
str q0, [dstin] stp val, val, [dstin]
tbnz count, 6, L(set96) tbnz count, 6, L(set96)
str q0, [dstend, -16] stp val, val, [dstend, -16]
tbz count, 5, 1f tbz count, 5, 1f
str q0, [dstin, 16] stp val, val, [dstin, 16]
str q0, [dstend, -32] stp val, val, [dstend, -32]
1: RETURN 1: ret
.p2align 4 .p2align 4
/* Set 64..96 bytes. Write 64 bytes from the start and /* Set 64..96 bytes. Write 64 bytes from the start and
32 bytes from the end. */ 32 bytes from the end. */
L(set96): L(set96):
str q0, [dstin, 16] stp val, val, [dstin, 16]
stp q0, q0, [dstin, 32] stp val, val, [dstin, 32]
stp q0, q0, [dstend, -32] stp val, val, [dstin, 48]
RETURN stp val, val, [dstend, -32]
stp val, val, [dstend, -16]
ret
.p2align 4 .p2align 4
L(set_long): L(set_long):
and valw, valw, 255 stp val, val, [dstin]
bic dst, dstin, 15 bic dst, dstin, 15
str q0, [dstin] #if DC_ZVA_THRESHOLD
cmp count, 160 cmp count, DC_ZVA_THRESHOLD
ccmp valw, 0, 0, hs ccmp val, 0, 0, cs
b.ne L(no_zva) b.eq L(zva_64)
#ifndef SKIP_ZVA_CHECK
mrs zva_val, dczid_el0
and zva_val, zva_val, 31
cmp zva_val, 4 /* ZVA size is 64 bytes. */
b.ne L(no_zva)
#endif #endif
str q0, [dst, 16] /* Small-size or non-zero memset does not use DC ZVA. */
stp q0, q0, [dst, 32] sub count, dstend, dst
bic dst, dst, 63
sub count, dstend, dst /* Count is now 64 too large. */
sub count, count, 128 /* Adjust count and bias for loop. */
/*
* Adjust count and bias for loop. By substracting extra 1 from count,
* it is easy to use tbz instruction to check whether loop tailing
* count is less than 33 bytes, so as to bypass 2 unneccesary stps.
*/
sub count, count, 64+16+1
#if DC_ZVA_THRESHOLD
/* Align loop on 16-byte boundary, this might be friendly to i-cache. */
nop
#endif
1: stp val, val, [dst, 16]
stp val, val, [dst, 32]
stp val, val, [dst, 48]
stp val, val, [dst, 64]!
subs count, count, 64
b.hs 1b
tbz count, 5, 1f /* Remaining count is less than 33 bytes? */
stp val, val, [dst, 16]
stp val, val, [dst, 32]
1: stp val, val, [dstend, -32]
stp val, val, [dstend, -16]
ret
#if DC_ZVA_THRESHOLD
.p2align 4 .p2align 4
L(zva_loop): L(zva_64):
add dst, dst, 64 stp val, val, [dst, 16]
dc zva, dst stp val, val, [dst, 32]
subs count, count, 64 stp val, val, [dst, 48]
b.hi L(zva_loop) bic dst, dst, 63
stp q0, q0, [dstend, -64]
stp q0, q0, [dstend, -32]
RETURN
L(no_zva): /*
sub count, dstend, dst /* Count is 16 too large. */ * Previous memory writes might cross cache line boundary, and cause
sub dst, dst, 16 /* Dst is biased by -32. */ * cache line partially dirty. Zeroing this kind of cache line using
sub count, count, 64 + 16 /* Adjust count and bias for loop. */ * DC ZVA will incur extra cost, for it requires loading untouched
L(no_zva_loop): * part of the line from memory before zeoring.
stp q0, q0, [dst, 32] *
stp q0, q0, [dst, 64]! * So, write the first 64 byte aligned block using stp to force
* fully dirty cache line.
*/
stp val, val, [dst, 64]
stp val, val, [dst, 80]
stp val, val, [dst, 96]
stp val, val, [dst, 112]
sub count, dstend, dst
/*
* Adjust count and bias for loop. By substracting extra 1 from count,
* it is easy to use tbz instruction to check whether loop tailing
* count is less than 33 bytes, so as to bypass 2 unneccesary stps.
*/
sub count, count, 128+64+64+1
add dst, dst, 128
nop
/* DC ZVA sets 64 bytes each time. */
1: dc zva, dst
add dst, dst, 64
subs count, count, 64 subs count, count, 64
b.hi L(no_zva_loop) b.hs 1b
stp q0, q0, [dstend, -64]
stp q0, q0, [dstend, -32] /*
RETURN * Write the last 64 byte aligned block using stp to force fully
* dirty cache line.
*/
stp val, val, [dst, 0]
stp val, val, [dst, 16]
stp val, val, [dst, 32]
stp val, val, [dst, 48]
tbz count, 5, 1f /* Remaining count is less than 33 bytes? */
stp val, val, [dst, 64]
stp val, val, [dst, 80]
1: stp val, val, [dstend, -32]
stp val, val, [dstend, -16]
ret
#endif
END (memset) END (memset)