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diff --git a/sysdeps/alpha/strncmp.S b/sysdeps/alpha/strncmp.S
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-/* Copyright (C) 1996, 1997, 2003 Free Software Foundation, Inc.
- Contributed by Richard Henderson (rth@tamu.edu)
- 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, write to the Free
- Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
- 02111-1307 USA. */
-
-/* Bytewise compare two null-terminated strings of length no longer than N. */
-
-#include <sysdep.h>
-
- .set noat
- .set noreorder
-
- .text
-
-ENTRY(strncmp)
-#ifdef PROF
- ldgp gp, 0(pv)
- lda AT, _mcount
- jsr AT, (AT), _mcount
- .prologue 1
-#else
- .prologue 0
-#endif
-
- xor a0, a1, t2 # e0 : are s1 and s2 co-aligned?
- beq a2, $zerolength # .. e1 :
- ldq_u t0, 0(a0) # e0 : give cache time to catch up
- ldq_u t1, 0(a1) # .. e1 :
- and t2, 7, t2 # e0 :
- and a0, 7, t4 # .. e1 : find s1 misalignment
- lda t3, -1 # e0 :
- addq a2, t4, a2 # .. e1 : bias count by s1 misalignment
- and a2, 7, t10 # e1 : ofs of last byte in last word
- srl a2, 3, a2 # .. e0 : remaining full words in count
- and a1, 7, t5 # e0 : find s2 misalignment
- bne t2, $unaligned # .. e1 :
-
- /* On entry to this basic block:
- t0 == the first word of s1.
- t1 == the first word of s2.
- t3 == -1. */
-
-$aligned:
- mskqh t3, a1, t3 # e0 : mask off leading garbage
- nop # .. e1 :
- ornot t1, t3, t1 # e0 :
- ornot t0, t3, t0 # .. e1 :
- cmpbge zero, t1, t7 # e0 : bits set iff null found
- beq a2, $eoc # .. e1 : check end of count
- unop # e0 :
- bne t7, $eos # .. e1 :
- unop # e0 :
- beq t10, $ant_loop # .. e1 :
-
- /* Aligned compare main loop.
- On entry to this basic block:
- t0 == an s1 word.
- t1 == an s2 word not containing a null. */
-
-$a_loop:
- xor t0, t1, t2 # e0 :
- bne t2, $wordcmp # .. e1 (zdb)
- ldq_u t1, 8(a1) # e0 :
- ldq_u t0, 8(a0) # .. e1 :
- subq a2, 1, a2 # e0 :
- addq a1, 8, a1 # .. e1 :
- addq a0, 8, a0 # e0 :
- beq a2, $eoc # .. e1 :
- cmpbge zero, t1, t7 # e0 :
- beq t7, $a_loop # .. e1 :
- unop # e0 :
- br $eos # .. e1 :
-
- /* Alternate aligned compare loop, for when there's no trailing
- bytes on the count. We have to avoid reading too much data. */
-$ant_loop:
- xor t0, t1, t2 # e0 :
- bne t2, $wordcmp # .. e1 (zdb)
- subq a2, 1, a2 # e0 :
- beq a2, $zerolength # .. e1 :
- ldq_u t1, 8(a1) # e0 :
- ldq_u t0, 8(a0) # .. e1 :
- addq a1, 8, a1 # e0 :
- addq a0, 8, a0 # .. e1 :
- cmpbge zero, t1, t7 # e0 :
- beq t7, $ant_loop # .. e1 :
- unop # e0 :
- br $eos # .. e1 :
-
- /* The two strings are not co-aligned. Align s1 and cope. */
-$unaligned:
- subq a1, t4, a1 # e0 :
- unop # :
-
- /* If s2 misalignment is larger than s2 misalignment, we need
- extra startup checks to avoid SEGV. */
-
- cmplt t4, t5, t8 # .. e1 :
- beq t8, $u_head # e1 :
-
- mskqh t3, t5, t3 # e0 :
- ornot t1, t3, t3 # e0 :
- cmpbge zero, t3, t7 # e1 : is there a zero?
- beq t7, $u_head # e1 :
-
- /* We've found a zero in the first partial word of s2. Align
- our current s1 and s2 words and compare what we've got. */
-
- extql t1, t5, t1 # e0 :
- lda t3, -1 # .. e1 :
- insql t1, a0, t1 # e0 :
- mskqh t3, a0, t3 # e0 :
- ornot t1, t3, t1 # e0 :
- ornot t0, t3, t0 # .. e1 :
- cmpbge zero, t1, t7 # e0 : find that zero again
- beq a2, $eoc # .. e1 : and finish up
- br $eos # e1 :
-
- .align 3
-$u_head:
- /* We know just enough now to be able to assemble the first
- full word of s2. We can still find a zero at the end of it.
-
- On entry to this basic block:
- t0 == first word of s1
- t1 == first partial word of s2. */
-
- ldq_u t2, 8(a1) # e0 : load second partial s2 word
- lda t3, -1 # .. e1 : create leading garbage mask
- extql t1, a1, t1 # e0 : create first s2 word
- mskqh t3, a0, t3 # e0 :
- extqh t2, a1, t4 # e0 :
- ornot t0, t3, t0 # .. e1 : kill s1 garbage
- or t1, t4, t1 # e0 : s2 word now complete
- ornot t1, t3, t1 # e1 : kill s2 garbage
- cmpbge zero, t0, t7 # e0 : find zero in first s1 word
- beq a2, $eoc # .. e1 :
- lda t3, -1 # e0 :
- bne t7, $eos # .. e1 :
- subq a2, 1, a2 # e0 :
- xor t0, t1, t4 # .. e1 : compare aligned words
- mskql t3, a1, t3 # e0 : mask out s2[1] bits we have seen
- bne t4, $wordcmp # .. e1 :
- or t2, t3, t3 # e0 :
- cmpbge zero, t3, t7 # e1 : find zero in high bits of s2[1]
- bne t7, $u_final # e1 :
-
- /* Unaligned copy main loop. In order to avoid reading too much,
- the loop is structured to detect zeros in aligned words from s2.
- This has, unfortunately, effectively pulled half of a loop
- iteration out into the head and half into the tail, but it does
- prevent nastiness from accumulating in the very thing we want
- to run as fast as possible.
-
- On entry to this basic block:
- t2 == the unshifted low-bits from the next s2 word. */
-
- .align 3
-$u_loop:
- extql t2, a1, t3 # e0 :
- ldq_u t2, 16(a1) # .. e1 : load next s2 high bits
- ldq_u t0, 8(a0) # e0 : load next s1 word
- addq a1, 8, a1 # .. e1 :
- addq a0, 8, a0 # e0 :
- nop # .. e1 :
- extqh t2, a1, t1 # e0 :
- cmpbge zero, t0, t7 # .. e1 : find zero in current s1 word
- or t1, t3, t1 # e0 :
- beq a2, $eoc # .. e1 : check for end of count
- subq a2, 1, a2 # e0 :
- bne t7, $eos # .. e1 :
- xor t0, t1, t4 # e0 : compare the words
- bne t4, $wordcmp # .. e1 (zdb)
- cmpbge zero, t2, t4 # e0 : find zero in next low bits
- beq t4, $u_loop # .. e1 (zdb)
-
- /* We've found a zero in the low bits of the last s2 word. Get
- the next s1 word and align them. */
-$u_final:
- ldq_u t0, 8(a0) # e1 :
- extql t2, a1, t1 # .. e0 :
- cmpbge zero, t1, t7 # e0 :
- bne a2, $eos # .. e1 :
-
- /* We've hit end of count. Zero everything after the count
- and compare whats left. */
-
- .align 3
-$eoc:
- mskql t0, t10, t0
- mskql t1, t10, t1
- unop
- cmpbge zero, t1, t7
-
- /* We've found a zero somewhere in a word we just read.
- On entry to this basic block:
- t0 == s1 word
- t1 == s2 word
- t7 == cmpbge mask containing the zero. */
-
-$eos:
- negq t7, t6 # e0 : create bytemask of valid data
- and t6, t7, t8 # e1 :
- subq t8, 1, t6 # e0 :
- or t6, t8, t7 # e1 :
- zapnot t0, t7, t0 # e0 : kill the garbage
- zapnot t1, t7, t1 # .. e1 :
- xor t0, t1, v0 # e0 : and compare
- beq v0, $done # .. e1 :
-
- /* Here we have two differing co-aligned words in t0 & t1.
- Bytewise compare them and return (t0 > t1 ? 1 : -1). */
- .align 3
-$wordcmp:
- cmpbge t0, t1, t2 # e0 : comparison yields bit mask of ge
- cmpbge t1, t0, t3 # .. e1 :
- xor t2, t3, t0 # e0 : bits set iff t0/t1 bytes differ
- negq t0, t1 # e1 : clear all but least bit
- and t0, t1, t0 # e0 :
- lda v0, -1 # .. e1 :
- and t0, t2, t1 # e0 : was bit set in t0 > t1?
- cmovne t1, 1, v0 # .. e1 (zdb)
-
-$done:
- ret # e1 :
-
- .align 3
-$zerolength:
- clr v0
- ret
-
- END(strncmp)
-libc_hidden_builtin_def (strncmp)
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