Alpha ev67 optimized implementation for strrchr.

diff --git a/sysdeps/alpha/alphaev67/strrchr.S b/sysdeps/alpha/alphaev67/strrchr.S
new file mode 100644 (file)
index 0000000..68874c9
--- /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)