111 lines
3.7 KiB
ArmAsm
111 lines
3.7 KiB
ArmAsm
/* Copyright (C) 1996, 1997 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library.
|
|
|
|
The GNU C Library is free software; you can redistribute it and/or
|
|
modify it under the terms of the GNU Library General Public License as
|
|
published by the Free Software Foundation; either version 2 of the
|
|
License, or (at your option) any later version.
|
|
|
|
The GNU C Library is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
Library General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Library General Public
|
|
License along with the GNU C Library; see the file COPYING.LIB. If not,
|
|
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
|
|
Boston, MA 02111-1307, USA. */
|
|
|
|
/* Return the address of the last occurrence of a given character
|
|
within a null-terminated string, or null if it is not found.
|
|
|
|
This is generally scheduled for the EV5 (got to look out for my own
|
|
interests :-), but with EV4 needs in mind. There are, in fact, fewer
|
|
stalls on the EV4 than there are on the EV5.
|
|
*/
|
|
|
|
#include <sysdep.h>
|
|
|
|
.set noreorder
|
|
.set noat
|
|
|
|
ENTRY(strrchr)
|
|
#ifdef PROF
|
|
ldgp gp, 0(pv)
|
|
lda AT, _mcount
|
|
jsr AT, (AT), _mcount
|
|
.prologue 1
|
|
#else
|
|
.prologue 0
|
|
#endif
|
|
|
|
zapnot a1, 1, a1 # e0 : zero extend our test character
|
|
mov zero, t6 # .. e1 : t6 is last match aligned addr
|
|
sll a1, 8, t5 # e0 : replicate our test character
|
|
mov zero, t7 # .. e1 : t7 is last match byte compare mask
|
|
or t5, a1, a1 # e0 :
|
|
ldq_u t0, 0(a0) # .. e1 : load first quadword
|
|
sll a1, 16, t5 # e0 :
|
|
andnot a0, 7, v0 # .. e1 : align source addr
|
|
or t5, a1, a1 # e0 :
|
|
lda t4, -1 # .. e1 : build garbage mask
|
|
sll a1, 32, t5 # e0 :
|
|
cmpbge zero, t0, t1 # .. e1 : bits set iff byte == zero
|
|
mskqh t4, a0, t4 # e0 :
|
|
or t5, a1, a1 # .. e1 : character replication complete
|
|
xor t0, a1, t2 # e0 : make bytes == c zero
|
|
cmpbge zero, t4, t4 # .. e1 : bits set iff byte is garbage
|
|
cmpbge zero, t2, t3 # e0 : bits set iff byte == c
|
|
andnot t1, t4, t1 # .. e1 : clear garbage from null test
|
|
andnot t3, t4, t3 # e0 : clear garbage from char test
|
|
bne t1, $eos # .. e1 : did we already hit the terminator?
|
|
|
|
/* Character search main loop */
|
|
$loop:
|
|
ldq t0, 8(v0) # e0 : load next quadword
|
|
cmovne t3, v0, t6 # .. e1 : save previous comparisons match
|
|
cmovne t3, t3, t7 # e0 :
|
|
addq v0, 8, v0 # .. e1 :
|
|
xor t0, a1, t2 # e0 :
|
|
cmpbge zero, t0, t1 # .. e1 : bits set iff byte == zero
|
|
cmpbge zero, t2, t3 # e0 : bits set iff byte == c
|
|
beq t1, $loop # .. e1 : if we havnt seen a null, loop
|
|
|
|
/* Mask out character matches after terminator */
|
|
$eos:
|
|
negq t1, t4 # e0 : isolate first null byte match
|
|
and t1, t4, t4 # e1 :
|
|
subq t4, 1, t5 # e0 : build a mask of the bytes upto...
|
|
or t4, t5, t4 # e1 : ... and including the null
|
|
|
|
and t3, t4, t3 # e0 : mask out char matches after null
|
|
cmovne t3, t3, t7 # .. e1 : save it, if match found
|
|
cmovne t3, v0, t6 # e0 :
|
|
|
|
/* Locate the address of the last matched character */
|
|
|
|
/* Retain the early exit for the ev4 -- the ev5 mispredict penalty
|
|
is 5 cycles -- the same as just falling through. */
|
|
beq t7, $retnull # .. e1 :
|
|
|
|
and t7, 0xf0, t2 # e0 : binary search for the high bit set
|
|
cmovne t2, t2, t7 # .. e1 (zdb)
|
|
cmovne t2, 4, t2 # e0 :
|
|
and t7, 0xcc, t1 # .. e1 :
|
|
cmovne t1, t1, t7 # e0 :
|
|
cmovne t1, 2, t1 # .. e1 :
|
|
and t7, 0xaa, t0 # e0 :
|
|
cmovne t0, 1, t0 # .. e1 (zdb)
|
|
addq t2, t1, t1 # e0 :
|
|
addq t6, t0, v0 # .. e1 : add our aligned base ptr to the mix
|
|
addq v0, t1, v0 # e0 :
|
|
ret # .. e1 :
|
|
|
|
$retnull:
|
|
mov zero, v0 # e0 :
|
|
ret # .. e1 :
|
|
|
|
END(strrchr)
|
|
|
|
weak_alias (strrchr, rindex)
|