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Diffstat (limited to 'sysdeps/alpha/alphaev67/strchr.S')
| -rw-r--r-- | sysdeps/alpha/alphaev67/strchr.S | 100 |
1 files changed, 100 insertions, 0 deletions
diff --git a/sysdeps/alpha/alphaev67/strchr.S b/sysdeps/alpha/alphaev67/strchr.S new file mode 100644 index 0000000000..328f8ec33a --- /dev/null +++ b/sysdeps/alpha/alphaev67/strchr.S @@ -0,0 +1,100 @@ +/* Copyright (C) 2000-2014 Free Software Foundation, Inc. + Contributed by Richard Henderson <rth@tamu.edu>, 1996. + 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 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 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(strchr) +#ifdef PROF + ldgp gp, 0(pv) + lda AT, _mcount + jsr AT, (AT), _mcount + .prologue 1 +#else + .prologue 0 +#endif + + ldq_u t0, 0(a0) # L : load first quadword Latency=3 + and a1, 0xff, t3 # E : 00000000000000ch + insbl a1, 1, t5 # U : 000000000000ch00 + insbl a1, 7, a2 # U : ch00000000000000 + + insbl t3, 6, a3 # U : 00ch000000000000 + or t5, t3, a1 # E : 000000000000chch + andnot a0, 7, v0 # E : align our loop pointer + lda t4, -1 # E : build garbage mask + + mskqh t4, a0, t4 # U : only want relevant part of first quad + or a2, a3, a2 # E : chch000000000000 + inswl a1, 2, t5 # E : 00000000chch0000 + inswl a1, 4, a3 # E : 0000chch00000000 + + or a1, a2, a1 # E : chch00000000chch + or a3, t5, t5 # E : 0000chchchch0000 + cmpbge zero, t0, t2 # E : bits set iff byte == zero + cmpbge zero, t4, t4 # E : bits set iff byte is garbage + + /* This quad is _very_ serialized. Lots of stalling happens */ + or t5, a1, a1 # E : chchchchchchchch + xor t0, a1, t1 # E : make bytes == c zero + cmpbge zero, t1, t3 # E : bits set iff byte == c + or t2, t3, t0 # E : bits set iff char match or zero match + + andnot t0, t4, t0 # E : clear garbage bits + cttz t0, a2 # U0 : speculative (in case we get a match) + nop # E : + bne t0, $found # U : + + /* + * Yuk. This loop is going to stall like crazy waiting for the + * data to be loaded. Not much can be done about it unless it's + * unrolled multiple times, which is generally unsafe. + */ +$loop: + ldq t0, 8(v0) # L : Latency=3 + addq v0, 8, v0 # E : + xor t0, a1, t1 # E : + cmpbge zero, t0, t2 # E : bits set iff byte == 0 + + cmpbge zero, t1, t3 # E : bits set iff byte == c + or t2, t3, t0 # E : + cttz t3, a2 # U0 : speculative (in case we get a match) + beq t0, $loop # U : + +$found: + negq t0, t1 # E : clear all but least set bit + and t0, t1, t0 # E : + and t0, t3, t1 # E : bit set iff byte was the char + addq v0, a2, v0 # E : Add in the bit number from above + + cmoveq t1, $31, v0 # E : Two mapping slots, latency = 2 + nop + nop + ret # L0 : + + END(strchr) + +weak_alias (strchr, index) +libc_hidden_builtin_def (strchr) |