--- /dev/null
+/* Copyright (C) 2000 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by David Mosberger (davidm@cs.arizona.edu).
+ EV6 optimized by Rick Gorton <rick.gorton@alpha-processor.com>.
+
+ 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. */
+
+#include <sysdep.h>
+
+ .arch ev6
+ .set noreorder
+ .set noat
+
+ENTRY(__memchr)
+#ifdef PROF
+ ldgp gp, 0(pv)
+ lda AT, _mcount
+ jsr AT, (AT), _mcount
+ .prologue 1
+#else
+ .prologue 0
+#endif
+
+ # Hack -- if someone passes in (size_t)-1, hoping to just
+ # search til the end of the address space, we will overflow
+ # below when we find the address of the last byte. Given
+ # that we will never have a 56-bit address space, cropping
+ # the length is the easiest way to avoid trouble.
+ zap $18, 0x80, $5 # U : Bound length
+ beq $18, $not_found # U :
+ ldq_u $1, 0($16) # L : load first quadword Latency=3
+ and $17, 0xff, $17 # E : L L U U : 00000000000000ch
+
+ insbl $17, 1, $2 # U : 000000000000ch00
+ cmpult $18, 9, $4 # E : small (< 1 quad) string?
+ or $2, $17, $17 # E : 000000000000chch
+ lda $3, -1($31) # E : U L L U
+
+ sll $17, 16, $2 # U : 00000000chch0000
+ addq $16, $5, $5 # E : Max search address
+ or $2, $17, $17 # E : 00000000chchchch
+ sll $17, 32, $2 # U : U L L U : chchchch00000000
+
+ or $2, $17, $17 # E : chchchchchchchch
+ extql $1, $16, $7 # U : $7 is upper bits
+ beq $4, $first_quad # U :
+ ldq_u $6, -1($5) # L : L U U L : eight or less bytes to search Latency=3
+
+ extqh $6, $16, $6 # U : 2 cycle stall for $6
+ mov $16, $0 # E :
+ nop # E :
+ or $7, $6, $1 # E : L U L U $1 = quadword starting at $16
+
+ # Deal with the case where at most 8 bytes remain to be searched
+ # in $1. E.g.:
+ # $18 = 6
+ # $1 = ????c6c5c4c3c2c1
+$last_quad:
+ negq $18, $6 # E :
+ xor $17, $1, $1 # E :
+ srl $3, $6, $6 # U : $6 = mask of $18 bits set
+ cmpbge $31, $1, $2 # E : L U L U
+
+ nop
+ nop
+ and $2, $6, $2 # E :
+ beq $2, $not_found # U : U L U L
+
+$found_it:
+#if defined(__alpha_fix__) && defined(__alpha_cix__)
+ /*
+ * Since we are guaranteed to have set one of the bits, we don't
+ * have to worry about coming back with a 0x40 out of cttz...
+ */
+ cttz $2, $3 # U0 :
+ addq $0, $3, $0 # E : All done
+ nop # E :
+ ret # L0 : L U L U
+#else
+ /*
+ * Slow and clunky. It can probably be improved.
+ * An exercise left for others.
+ */
+ negq $2, $3 # E :
+ and $2, $3, $2 # E :
+ and $2, 0x0f, $1 # E :
+ addq $0, 4, $3 # E :
+
+ cmoveq $1, $3, $0 # E : Latency 2, extra map cycle
+ nop # E : keep with cmov
+ and $2, 0x33, $1 # E :
+ addq $0, 2, $3 # E : U L U L : 2 cycle stall on $0
+
+ cmoveq $1, $3, $0 # E : Latency 2, extra map cycle
+ nop # E : keep with cmov
+ and $2, 0x55, $1 # E :
+ addq $0, 1, $3 # E : U L U L : 2 cycle stall on $0
+
+ cmoveq $1, $3, $0 # E : Latency 2, extra map cycle
+ nop
+ nop
+ ret # L0 : L U L U
+#endif
+
+ # Deal with the case where $18 > 8 bytes remain to be
+ # searched. $16 may not be aligned.
+ .align 4
+$first_quad:
+ andnot $16, 0x7, $0 # E :
+ insqh $3, $16, $2 # U : $2 = 0000ffffffffffff ($16<0:2> ff)
+ xor $1, $17, $1 # E :
+ or $1, $2, $1 # E : U L U L $1 = ====ffffffffffff
+
+ cmpbge $31, $1, $2 # E :
+ bne $2, $found_it # U :
+ # At least one byte left to process.
+ ldq $1, 8($0) # L :
+ subq $5, 1, $18 # E : U L U L
+
+ addq $0, 8, $0 # E :
+ # Make $18 point to last quad to be accessed (the
+ # last quad may or may not be partial).
+ andnot $18, 0x7, $18 # E :
+ cmpult $0, $18, $2 # E :
+ beq $2, $final # U : U L U L
+
+ # At least two quads remain to be accessed.
+
+ subq $18, $0, $4 # E : $4 <- nr quads to be processed
+ and $4, 8, $4 # E : odd number of quads?
+ bne $4, $odd_quad_count # U :
+ # At least three quads remain to be accessed
+ mov $1, $4 # E : L U L U : move prefetched value to correct reg
+
+ .align 4
+$unrolled_loop:
+ ldq $1, 8($0) # L : prefetch $1
+ xor $17, $4, $2 # E :
+ cmpbge $31, $2, $2 # E :
+ bne $2, $found_it # U : U L U L
+
+ addq $0, 8, $0 # E :
+ nop # E :
+ nop # E :
+ nop # E :
+
+$odd_quad_count:
+ xor $17, $1, $2 # E :
+ ldq $4, 8($0) # L : prefetch $4
+ cmpbge $31, $2, $2 # E :
+ addq $0, 8, $6 # E :
+
+ bne $2, $found_it # U :
+ cmpult $6, $18, $6 # E :
+ addq $0, 8, $0 # E :
+ nop # E :
+
+ bne $6, $unrolled_loop # U :
+ mov $4, $1 # E : move prefetched value into $1
+ nop # E :
+ nop # E :
+
+$final: subq $5, $0, $18 # E : $18 <- number of bytes left to do
+ nop # E :
+ nop # E :
+ bne $18, $last_quad # U :
+
+$not_found:
+ mov $31, $0 # E :
+ nop # E :
+ nop # E :
+ ret # L0 :
+
+ END(__memchr)
+
+weak_alias (__memchr, memchr)
+#if !__BOUNDED_POINTERS__
+weak_alias (__memchr, __ubp_memchr)
+#endif
projects / platform / upstream / glibc.git / commitdiff