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Diffstat (limited to 'sysdeps/alpha/strchr.S')
| -rw-r--r-- | sysdeps/alpha/strchr.S | 94 |
1 files changed, 94 insertions, 0 deletions
diff --git a/sysdeps/alpha/strchr.S b/sysdeps/alpha/strchr.S new file mode 100644 index 0000000000..ba46ab3c90 --- /dev/null +++ b/sysdeps/alpha/strchr.S @@ -0,0 +1,94 @@ +/* Copyright (C) 1996-2014 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Richard Henderson (rth@tamu.edu) + + 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. + + This is generally scheduled for the EV5 (got to look out for my own + interests :-), but with EV4 needs in mind. There *should* be no more + stalls for the EV4 than there are for the EV5. +*/ + +#include <sysdep.h> + + .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 + + zapnot a1, 1, a1 # e0 : zero extend the search character + ldq_u t0, 0(a0) # .. e1 : load first quadword + sll a1, 8, t5 # e0 : replicate the search character + andnot a0, 7, v0 # .. e1 : align our loop pointer + or t5, a1, a1 # e0 : + lda t4, -1 # .. e1 : build garbage mask + sll a1, 16, t5 # e0 : + cmpbge zero, t0, t2 # .. e1 : bits set iff byte == zero + mskqh t4, a0, t4 # e0 : + or t5, a1, a1 # .. e1 : + sll a1, 32, t5 # e0 : + cmpbge zero, t4, t4 # .. e1 : bits set iff byte is garbage + or t5, a1, a1 # e0 : + xor t0, a1, t1 # .. e1 : make bytes == c zero + cmpbge zero, t1, t3 # e0 : bits set iff byte == c + or t2, t3, t0 # e1 : bits set iff char match or zero match + andnot t0, t4, t0 # e0 : clear garbage bits + bne t0, $found # .. e1 (zdb) + +$loop: ldq t0, 8(v0) # e0 : + addq v0, 8, v0 # .. e1 : + nop # e0 : + xor t0, a1, t1 # .. e1 (ev5 data stall) + cmpbge zero, t0, t2 # e0 : bits set iff byte == 0 + cmpbge zero, t1, t3 # .. e1 : bits set iff byte == c + or t2, t3, t0 # e0 : + beq t0, $loop # .. e1 (zdb) + +$found: negq t0, t1 # e0 : clear all but least set bit + and t0, t1, t0 # e1 (stall) + + and t0, t3, t1 # e0 : bit set iff byte was the char + beq t1, $retnull # .. e1 (zdb) + + and t0, 0xf0, t2 # e0 : binary search for that set bit + and t0, 0xcc, t3 # .. e1 : + and t0, 0xaa, t4 # e0 : + cmovne t2, 4, t2 # .. e1 : + cmovne t3, 2, t3 # e0 : + cmovne t4, 1, t4 # .. e1 : + addq t2, t3, t2 # e0 : + addq v0, t4, v0 # .. e1 : + addq v0, t2, v0 # e0 : + ret # .. e1 : + +$retnull: + mov zero, v0 # e0 : + ret # .. e1 : + + END(strchr) + +weak_alias (strchr, index) +libc_hidden_builtin_def (strchr) |