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Provide a BWX version of alpha_copystr() and patch it into place if 

the system supports the BWX extension.  The inner loop of the BWX
version is 42% shorter than the non-BWX version (7 vs 12 insns).
This commit is contained in:
thorpej 2021-07-07 03:30:35 +00:00
parent ceb097d8a2
commit ee112ce142
2 changed files with 51 additions and 4 deletions
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43
sys/arch/alpha/alpha/locore.s
View File

@ -1,4 +1,4 @@
/* $NetBSD: locore.s,v 1.138 2021/07/07 02:44:04 thorpej Exp $ */
/* $NetBSD: locore.s,v 1.139 2021/07/07 03:30:35 thorpej Exp $ */
/*-
* Copyright (c) 1999, 2000, 2019 The NetBSD Foundation, Inc.
@ -67,7 +67,7 @@
#include <machine/asm.h>
__KERNEL_RCSID(0, "$NetBSD: locore.s,v 1.138 2021/07/07 02:44:04 thorpej Exp $");
__KERNEL_RCSID(0, "$NetBSD: locore.s,v 1.139 2021/07/07 03:30:35 thorpej Exp $");
#include "assym.h"
@ -902,6 +902,44 @@ LEAF_NOPROFILE(lwp_trampoline, 0)
/*
* alpha_copystr(const void *from, void *to, size_t len, size_t *donep)
*/
.arch ev56
LEAF(alpha_copystr_bwx, 4)
LDGP(pv)
mov a2, t0 /* t0 = i = len */
beq a2, 5f /* if (len == 0), bail */
1: ldbu t1, 0(a0) /* t1 = *from */
subl a2, 1, a2 /* len-- */
addq a0, 1, a0 /* from++ */
stb t1, 0(a1) /* *to = t1 */
beq t1, 2f /* if (t1 == '\0'), bail out */
addq a1, 1, a1 /* to++ */
bne a2, 1b /* if (len != 0), copy more */
2: beq a3, 3f /* if (lenp != NULL) */
subl t0, a2, t0 /* *lenp = (i - len) */
stq t0, 0(a3)
3: bne t1, 4f /* *from != '\0'; leave in a huff */
mov zero, v0 /* return 0. */
RET
4: ldiq v0, ENAMETOOLONG
RET
5: ldiq t1, 1 /* fool the test above... */
br zero, 2b
nop /* pad to same length as... */
nop /* non-BWX version. */
nop
nop
nop
EXPORT(alpha_copystr_bwx_end)
END(alpha_copystr_bwx)
.arch ev4
LEAF(alpha_copystr, 4)
LDGP(pv)
@ -935,6 +973,7 @@ LEAF(alpha_copystr, 4)
5: ldiq t1, 1 /* fool the test above... */
br zero, 2b
EXPORT(alpha_copystr_end)
END(alpha_copystr)
NESTED(copyinstr, 4, 16, ra, IM_RA|IM_S0, 0)

12
sys/arch/alpha/alpha/patch.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: patch.c,v 1.5 2020/09/04 03:41:49 thorpej Exp $ */
/* $NetBSD: patch.c,v 1.6 2021/07/07 03:30:35 thorpej Exp $ */
/*-
* Copyright (c) 2007 The NetBSD Foundation, Inc.
@ -35,7 +35,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: patch.c,v 1.5 2020/09/04 03:41:49 thorpej Exp $");
__KERNEL_RCSID(0, "$NetBSD: patch.c,v 1.6 2021/07/07 03:30:35 thorpej Exp $");
#include "opt_multiprocessor.h"
@ -57,6 +57,9 @@ void _membar_sync_end(void);
void _membar_sync_mp(void);
void _membar_sync_mp_end(void);
extern char alpha_copystr_bwx[], alpha_copystr_bwx_end[];
extern char alpha_copystr[], alpha_copystr_end[];
static void __attribute__((__unused__))
patchfunc(void *from_s, void *from_e, void *to_s, void *to_e)
{
@ -85,6 +88,11 @@ alpha_patch(bool is_mp)
* kernel code.
*/
if (cpu_amask & ALPHA_AMASK_BWX) {
patchfunc(alpha_copystr_bwx, alpha_copystr_bwx_end,
alpha_copystr, alpha_copystr_end);
}
#if defined(MULTIPROCESSOR)
if (is_mp) {
KASSERT(curcpu()->ci_flags & CPUF_PRIMARY);