diff options
Diffstat (limited to 'sysdeps/alpha/strrchr.S')
| -rw-r--r-- | sysdeps/alpha/strrchr.S | 110 |
1 files changed, 110 insertions, 0 deletions
diff --git a/sysdeps/alpha/strrchr.S b/sysdeps/alpha/strrchr.S new file mode 100644 index 0000000000..e85f0cf464 --- /dev/null +++ b/sysdeps/alpha/strrchr.S @@ -0,0 +1,110 @@ +/* Copyright (C) 1996-2014 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 Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 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 + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library. If not, see + <http://www.gnu.org/licenses/>. */ + +/* 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 + + and a1, 0xff, 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) +libc_hidden_builtin_def (strrchr) |