diff options
Diffstat (limited to 'sysdeps/alpha/alphaev67/strrchr.S')
| -rw-r--r-- | sysdeps/alpha/alphaev67/strrchr.S | 117 |
1 files changed, 117 insertions, 0 deletions
diff --git a/sysdeps/alpha/alphaev67/strrchr.S b/sysdeps/alpha/alphaev67/strrchr.S new file mode 100644 index 0000000000..68874c966e --- /dev/null +++ b/sysdeps/alpha/alphaev67/strrchr.S @@ -0,0 +1,117 @@ +/* Copyright (C) 2000 Free Software Foundation, Inc. + EV67 optimized by Rick Gorton <rick.gorton@alpha-processor.com>. + + 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. */ + +#include <sysdep.h> + + .arch ev6 + .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 + + and a1, 0xff, t2 # E : 00000000000000ch + insbl a1, 1, t4 # U : 000000000000ch00 + insbl a1, 2, t5 # U : 0000000000ch0000 + ldq_u t0, 0(a0) # L : load first quadword Latency=3 + + mov zero, t6 # E : t6 is last match aligned addr + or t2, t4, a1 # E : 000000000000chch + sll t5, 8, t3 # U : 00000000ch000000 + mov zero, t8 # E : t8 is last match byte compare mask + + andnot a0, 7, v0 # E : align source addr + or t5, t3, t3 # E : 00000000chch0000 + sll a1, 32, t2 # U : 0000chch00000000 + sll a1, 48, t4 # U : chch000000000000 + + or t4, a1, a1 # E : chch00000000chch + or t2, t3, t2 # E : 0000chchchch0000 + or a1, t2, a1 # E : chchchchchchchch + lda t5, -1 # E : build garbage mask + + cmpbge zero, t0, t1 # E : bits set iff byte == zero + mskqh t5, a0, t4 # E : Complete garbage mask + xor t0, a1, t2 # E : make bytes == c zero + cmpbge zero, t4, t4 # E : bits set iff byte is garbage + + cmpbge zero, t2, t3 # E : bits set iff byte == c + andnot t1, t4, t1 # E : clear garbage from null test + andnot t3, t4, t3 # E : clear garbage from char test + bne t1, $eos # U : did we already hit the terminator? + + /* Character search main loop */ +$loop: + ldq t0, 8(v0) # L : load next quadword + cmovne t3, v0, t6 # E : save previous comparisons match + nop # : Latency=2, extra map slot (keep nop with cmov) + nop + + cmovne t3, t3, t8 # E : Latency=2, extra map slot + nop # : keep with cmovne + addq v0, 8, v0 # E : + xor t0, a1, t2 # E : + + cmpbge zero, t0, t1 # E : bits set iff byte == zero + cmpbge zero, t2, t3 # E : bits set iff byte == c + beq t1, $loop # U : if we havnt seen a null, loop + nop + + /* Mask out character matches after terminator */ +$eos: + negq t1, t4 # E : isolate first null byte match + and t1, t4, t4 # E : + subq t4, 1, t5 # E : build a mask of the bytes upto... + or t4, t5, t4 # E : ... and including the null + + and t3, t4, t3 # E : mask out char matches after null + cmovne t3, t3, t8 # E : save it, if match found Latency=2, extra map slot + nop # : Keep with cmovne + nop + + cmovne t3, v0, t6 # E : + nop # : Keep with cmovne + /* Locate the address of the last matched character */ + ctlz t8, t2 # U0 : Latency=3 (0x40 for t8=0) + nop + + cmoveq t8, 0x3f, t2 # E : Compensate for case when no match is seen + nop # E : hide the cmov latency (2) behind ctlz latency + lda t5, 0x3f($31) # E : + subq t5, t2, t5 # E : Normalize leading zero count + + addq t6, t5, v0 # E : and add to quadword address + ret # L0 : Latency=3 + nop + nop + +END(strrchr) + +weak_alias (strrchr, rindex) |