linux/arch/arc/lib/strcmp-archs.S
Vineet Gupta 86effd0dc6 ARC: dw2 unwind: enable cfi pseudo ops in string lib
This uses a new set of annoations viz. ENTRY_CFI/END_CFI to enabel cfi
ops generation.

Note that we didn't change the normal ENTRY/EXIT as we don't actually
want unwind info in the trap/exception/interrutp handlers which use
these, as unwinder then gets confused (it keeps recursing vs. stopping).
Semantically these are leaf routines and unwinding should stop when it
hits those routines.

Before
------

    28.52%     1.19%          9929  hackbench  libuClibc-1.0.17.so   [.] __write_nocancel
            |
            ---__write_nocancel
               |--8.95%--EV_Trap
               |           --8.25%--sys_write
               |                     |--3.93%--sock_write_iter
     ...
               |--2.62%--memset   <==== [LEAF entry as no unwind info]
                         ^^^^^^

After
-----

    29.46%     1.24%         13622  hackbench  libuClibc-1.0.17.so   [.] __write_nocancel
            |
            ---__write_nocancel
               |--9.31%--EV_Trap
               |           --8.62%--sys_write
               |                     |--4.17%--sock_write_iter
     ...
               |--6.19%--sys_write
               |           --6.19%--sock_write_iter
               |                     unix_stream_sendmsg
               |                     |--1.62%--sock_alloc_send_pskb
               |                     |--0.89%--sock_def_readable
               |                     |--0.88%--_raw_spin_unlock_irqrestore
               |                     |--0.69%--memset
               |                     |         ^^^^^^     <==== [now in proper callframe]
               |                     |
               |                      --0.52%--skb_copy_datagram_from_iter

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2016-09-30 14:48:22 -07:00

79 lines
1.3 KiB
ArmAsm

/*
* Copyright (C) 2014-15 Synopsys, Inc. (www.synopsys.com)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/linkage.h>
ENTRY_CFI(strcmp)
or r2, r0, r1
bmsk_s r2, r2, 1
brne r2, 0, @.Lcharloop
;;; s1 and s2 are word aligned
ld.ab r2, [r0, 4]
mov_s r12, 0x01010101
ror r11, r12
.align 4
.LwordLoop:
ld.ab r3, [r1, 4]
;; Detect NULL char in str1
sub r4, r2, r12
ld.ab r5, [r0, 4]
bic r4, r4, r2
and r4, r4, r11
brne.d.nt r4, 0, .LfoundNULL
;; Check if the read locations are the same
cmp r2, r3
beq.d .LwordLoop
mov.eq r2, r5
;; A match is found, spot it out
#ifdef __LITTLE_ENDIAN__
swape r3, r3
mov_s r0, 1
swape r2, r2
#else
mov_s r0, 1
#endif
cmp_s r2, r3
j_s.d [blink]
bset.lo r0, r0, 31
.align 4
.LfoundNULL:
#ifdef __BIG_ENDIAN__
swape r4, r4
swape r2, r2
swape r3, r3
#endif
;; Find null byte
ffs r0, r4
bmsk r2, r2, r0
bmsk r3, r3, r0
swape r2, r2
swape r3, r3
;; make the return value
sub.f r0, r2, r3
mov.hi r0, 1
j_s.d [blink]
bset.lo r0, r0, 31
.align 4
.Lcharloop:
ldb.ab r2, [r0, 1]
ldb.ab r3, [r1, 1]
nop
breq r2, 0, .Lcmpend
breq r2, r3, .Lcharloop
.align 4
.Lcmpend:
j_s.d [blink]
sub r0, r2, r3
END_CFI(strcmp)