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glibc/sysdeps/powerpc/powerpc32/power7/memchr.S

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powerpc: Various P7-optimized string functions
2010-08-19 14:38:41 +00:00
/* Optimized memchr implementation for PowerPC32/POWER7 using cmpb insn.
Update copyright notices with scripts/update-copyrights.
2013-01-02 19:01:50 +00:00
Copyright (C) 2010-2013 Free Software Foundation, Inc.
powerpc: Various P7-optimized string functions
2010-08-19 14:38:41 +00:00
Contributed by Luis Machado <luisgpm@br.ibm.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
Replace FSF snail mail address with URLs.
2012-02-09 23:18:22 +00:00
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
powerpc: Various P7-optimized string functions
2010-08-19 14:38:41 +00:00
#include <sysdep.h>
/* int [r3] memchr (char *s [r3], int byte [r4], int size [r5]) */
.machine power7
Remove powerpc32 bounded-pointers code.
2013-02-28 21:23:47 +00:00
ENTRY (__memchr)
powerpc: Various P7-optimized string functions
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CALL_MCOUNT
dcbt 0,r3
clrrwi r8,r3,2
rlwimi r4,r4,8,16,23
rlwimi r4,r4,16,0,15
add r7,r3,r5 /* Calculate the last acceptable address. */
cmplwi r5,16
ble L(small_range)
[Powerpc] Tune/optimize powerpc{32,64}/power7/memchr.S. Assorted tweaking, twisting and tuning to squeeze a few additional cycles out of the memchr code. Changes include bypassing the shift pairs (sld,srd) when they are not required, and unrolling the small_loop that handles short and trailing strings. Per scrollpipe data measuring aligned strings for 64-bit, these changes save between five and eight cycles (9-13% overall) for short strings (<32), Longer aligned strings see slight improvement of 1-3% due to bypassing the shifts and the instruction rearranging.
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cmplw cr7,r3,r7 /* Compare the starting address (r3) with the
ending address (r7). If (r3 >= r7), the size
passed in is zero or negative. */
powerpc: Various P7-optimized string functions
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ble cr7,L(proceed)
[Powerpc] Tune/optimize powerpc{32,64}/power7/memchr.S. Assorted tweaking, twisting and tuning to squeeze a few additional cycles out of the memchr code. Changes include bypassing the shift pairs (sld,srd) when they are not required, and unrolling the small_loop that handles short and trailing strings. Per scrollpipe data measuring aligned strings for 64-bit, these changes save between five and eight cycles (9-13% overall) for short strings (<32), Longer aligned strings see slight improvement of 1-3% due to bypassing the shifts and the instruction rearranging.
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li r7,-1 /* Artificially set our ending address (r7)
such that we will exit early. */
powerpc: Various P7-optimized string functions
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L(proceed):
rlwinm r6,r3,3,27,28 /* Calculate padding. */
[Powerpc] Tune/optimize powerpc{32,64}/power7/memchr.S. Assorted tweaking, twisting and tuning to squeeze a few additional cycles out of the memchr code. Changes include bypassing the shift pairs (sld,srd) when they are not required, and unrolling the small_loop that handles short and trailing strings. Per scrollpipe data measuring aligned strings for 64-bit, these changes save between five and eight cycles (9-13% overall) for short strings (<32), Longer aligned strings see slight improvement of 1-3% due to bypassing the shifts and the instruction rearranging.
2012-08-21 19:20:55 +00:00
cmpli cr6,r6,0 /* cr6 == Do we have padding? */
powerpc: Various P7-optimized string functions
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lwz r12,0(r8) /* Load word from memory. */
Fix spelling errors in sysdeps/powerpc files.
2013-01-07 17:20:53 +00:00
cmpb r10,r12,r4 /* Check for BYTEs in WORD1. */
[Powerpc] Tune/optimize powerpc{32,64}/power7/memchr.S. Assorted tweaking, twisting and tuning to squeeze a few additional cycles out of the memchr code. Changes include bypassing the shift pairs (sld,srd) when they are not required, and unrolling the small_loop that handles short and trailing strings. Per scrollpipe data measuring aligned strings for 64-bit, these changes save between five and eight cycles (9-13% overall) for short strings (<32), Longer aligned strings see slight improvement of 1-3% due to bypassing the shifts and the instruction rearranging.
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beq cr6,L(proceed_no_padding)
powerpc: Various P7-optimized string functions
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slw r10,r10,r6
srw r10,r10,r6
[Powerpc] Tune/optimize powerpc{32,64}/power7/memchr.S. Assorted tweaking, twisting and tuning to squeeze a few additional cycles out of the memchr code. Changes include bypassing the shift pairs (sld,srd) when they are not required, and unrolling the small_loop that handles short and trailing strings. Per scrollpipe data measuring aligned strings for 64-bit, these changes save between five and eight cycles (9-13% overall) for short strings (<32), Longer aligned strings see slight improvement of 1-3% due to bypassing the shifts and the instruction rearranging.
2012-08-21 19:20:55 +00:00
L(proceed_no_padding):
cmplwi cr7,r10,0 /* If r10 == 0, no BYTEs have been found. */
powerpc: Various P7-optimized string functions
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bne cr7,L(done)
/* Are we done already? */
addi r9,r8,4
cmplw cr6,r9,r7
bge cr6,L(null)
mtcrf 0x01,r8
/* Are we now aligned to a doubleword boundary? If so, skip to
the main loop. Otherwise, go through the alignment code. */
bt 29,L(loop_setup)
/* Handle WORD2 of pair. */
lwzu r12,4(r8)
cmpb r10,r12,r4
cmplwi cr7,r10,0
bne cr7,L(done)
/* Are we done already? */
addi r9,r8,4
cmplw cr6,r9,r7
bge cr6,L(null)
L(loop_setup):
sub r5,r7,r9
srwi r6,r5,3 /* Number of loop iterations. */
[Powerpc] Tune/optimize powerpc{32,64}/power7/memchr.S. Assorted tweaking, twisting and tuning to squeeze a few additional cycles out of the memchr code. Changes include bypassing the shift pairs (sld,srd) when they are not required, and unrolling the small_loop that handles short and trailing strings. Per scrollpipe data measuring aligned strings for 64-bit, these changes save between five and eight cycles (9-13% overall) for short strings (<32), Longer aligned strings see slight improvement of 1-3% due to bypassing the shifts and the instruction rearranging.
2012-08-21 19:20:55 +00:00
mtctr r6 /* Setup the counter. */
powerpc: Various P7-optimized string functions
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b L(loop)
/* Main loop to look for BYTE backwards in the string. Since
it's a small loop (< 8 instructions), align it to 32-bytes. */
.p2align 5
L(loop):
/* Load two words, compare and merge in a
single register for speed. This is an attempt
to speed up the byte-checking process for bigger strings. */
lwz r12,4(r8)
lwzu r11,8(r8)
cmpb r10,r12,r4
cmpb r9,r11,r4
or r5,r9,r10 /* Merge everything in one word. */
cmplwi cr7,r5,0
bne cr7,L(found)
bdnz L(loop)
[Powerpc] Tune/optimize powerpc{32,64}/power7/memchr.S. Assorted tweaking, twisting and tuning to squeeze a few additional cycles out of the memchr code. Changes include bypassing the shift pairs (sld,srd) when they are not required, and unrolling the small_loop that handles short and trailing strings. Per scrollpipe data measuring aligned strings for 64-bit, these changes save between five and eight cycles (9-13% overall) for short strings (<32), Longer aligned strings see slight improvement of 1-3% due to bypassing the shifts and the instruction rearranging.
2012-08-21 19:20:55 +00:00
powerpc: Various P7-optimized string functions
2010-08-19 14:38:41 +00:00
/* We're here because the counter reached 0, and that means we
[Powerpc] Tune/optimize powerpc{32,64}/power7/memchr.S. Assorted tweaking, twisting and tuning to squeeze a few additional cycles out of the memchr code. Changes include bypassing the shift pairs (sld,srd) when they are not required, and unrolling the small_loop that handles short and trailing strings. Per scrollpipe data measuring aligned strings for 64-bit, these changes save between five and eight cycles (9-13% overall) for short strings (<32), Longer aligned strings see slight improvement of 1-3% due to bypassing the shifts and the instruction rearranging.
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didn't have any matches for BYTE in the whole range. */
subi r11,r7,4
cmplw cr6,r8,r11
powerpc: Various P7-optimized string functions
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blt cr6,L(loop_small)
b L(null)
/* OK, one (or both) of the words contains BYTE. Check
the first word and decrement the address in case the first
word really contains BYTE. */
.align 4
L(found):
cmplwi cr6,r10,0
addi r8,r8,-4
bne cr6,L(done)
/* BYTE must be in the second word. Adjust the address
again and move the result of cmpb to r10 so we can calculate the
pointer. */
mr r10,r9
addi r8,r8,4
/* r10 has the output of the cmpb instruction, that is, it contains
0xff in the same position as BYTE in the original
word from the string. Use that to calculate the pointer.
[Powerpc] Tune/optimize powerpc{32,64}/power7/memchr.S. Assorted tweaking, twisting and tuning to squeeze a few additional cycles out of the memchr code. Changes include bypassing the shift pairs (sld,srd) when they are not required, and unrolling the small_loop that handles short and trailing strings. Per scrollpipe data measuring aligned strings for 64-bit, these changes save between five and eight cycles (9-13% overall) for short strings (<32), Longer aligned strings see slight improvement of 1-3% due to bypassing the shifts and the instruction rearranging.
2012-08-21 19:20:55 +00:00
We need to make sure BYTE is *before* the end of the range. */
powerpc: Various P7-optimized string functions
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L(done):
cntlzw r0,r10 /* Count leading zeroes before the match. */
srwi r0,r0,3 /* Convert leading zeroes to bytes. */
add r3,r8,r0
cmplw r3,r7
bge L(null)
blr
.align 4
L(null):
li r3,0
blr
/* Deals with size <= 16. */
.align 4
L(small_range):
cmplwi r5,0
rlwinm r6,r3,3,27,28 /* Calculate padding. */
[Powerpc] Tune/optimize powerpc{32,64}/power7/memchr.S. Assorted tweaking, twisting and tuning to squeeze a few additional cycles out of the memchr code. Changes include bypassing the shift pairs (sld,srd) when they are not required, and unrolling the small_loop that handles short and trailing strings. Per scrollpipe data measuring aligned strings for 64-bit, these changes save between five and eight cycles (9-13% overall) for short strings (<32), Longer aligned strings see slight improvement of 1-3% due to bypassing the shifts and the instruction rearranging.
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beq L(null) /* This branch is for the cmplwi r5,0 above */
powerpc: Various P7-optimized string functions
2010-08-19 14:38:41 +00:00
lwz r12,0(r8) /* Load word from memory. */
[Powerpc] Tune/optimize powerpc{32,64}/power7/memchr.S. Assorted tweaking, twisting and tuning to squeeze a few additional cycles out of the memchr code. Changes include bypassing the shift pairs (sld,srd) when they are not required, and unrolling the small_loop that handles short and trailing strings. Per scrollpipe data measuring aligned strings for 64-bit, these changes save between five and eight cycles (9-13% overall) for short strings (<32), Longer aligned strings see slight improvement of 1-3% due to bypassing the shifts and the instruction rearranging.
2012-08-21 19:20:55 +00:00
cmplwi cr6,r6,0 /* cr6 == Do we have padding? */
powerpc: Various P7-optimized string functions
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cmpb r10,r12,r4 /* Check for BYTE in DWORD1. */
[Powerpc] Tune/optimize powerpc{32,64}/power7/memchr.S. Assorted tweaking, twisting and tuning to squeeze a few additional cycles out of the memchr code. Changes include bypassing the shift pairs (sld,srd) when they are not required, and unrolling the small_loop that handles short and trailing strings. Per scrollpipe data measuring aligned strings for 64-bit, these changes save between five and eight cycles (9-13% overall) for short strings (<32), Longer aligned strings see slight improvement of 1-3% due to bypassing the shifts and the instruction rearranging.
2012-08-21 19:20:55 +00:00
beq cr6,L(small_no_padding)
powerpc: Various P7-optimized string functions
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slw r10,r10,r6
srw r10,r10,r6
[Powerpc] Tune/optimize powerpc{32,64}/power7/memchr.S. Assorted tweaking, twisting and tuning to squeeze a few additional cycles out of the memchr code. Changes include bypassing the shift pairs (sld,srd) when they are not required, and unrolling the small_loop that handles short and trailing strings. Per scrollpipe data measuring aligned strings for 64-bit, these changes save between five and eight cycles (9-13% overall) for short strings (<32), Longer aligned strings see slight improvement of 1-3% due to bypassing the shifts and the instruction rearranging.
2012-08-21 19:20:55 +00:00
L(small_no_padding):
powerpc: Various P7-optimized string functions
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cmplwi cr7,r10,0
bne cr7,L(done)
/* Are we done already? */
addi r9,r8,4
cmplw r9,r7
bge L(null)
[Powerpc] Tune/optimize powerpc{32,64}/power7/memchr.S. Assorted tweaking, twisting and tuning to squeeze a few additional cycles out of the memchr code. Changes include bypassing the shift pairs (sld,srd) when they are not required, and unrolling the small_loop that handles short and trailing strings. Per scrollpipe data measuring aligned strings for 64-bit, these changes save between five and eight cycles (9-13% overall) for short strings (<32), Longer aligned strings see slight improvement of 1-3% due to bypassing the shifts and the instruction rearranging.
2012-08-21 19:20:55 +00:00
L(loop_small): /* loop_small has been unrolled. */
powerpc: Various P7-optimized string functions
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lwzu r12,4(r8)
cmpb r10,r12,r4
addi r9,r8,4
cmplwi cr6,r10,0
[Powerpc] Tune/optimize powerpc{32,64}/power7/memchr.S. Assorted tweaking, twisting and tuning to squeeze a few additional cycles out of the memchr code. Changes include bypassing the shift pairs (sld,srd) when they are not required, and unrolling the small_loop that handles short and trailing strings. Per scrollpipe data measuring aligned strings for 64-bit, these changes save between five and eight cycles (9-13% overall) for short strings (<32), Longer aligned strings see slight improvement of 1-3% due to bypassing the shifts and the instruction rearranging.
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cmplw r9,r7
powerpc: Various P7-optimized string functions
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bne cr6,L(done)
[Powerpc] Tune/optimize powerpc{32,64}/power7/memchr.S. Assorted tweaking, twisting and tuning to squeeze a few additional cycles out of the memchr code. Changes include bypassing the shift pairs (sld,srd) when they are not required, and unrolling the small_loop that handles short and trailing strings. Per scrollpipe data measuring aligned strings for 64-bit, these changes save between five and eight cycles (9-13% overall) for short strings (<32), Longer aligned strings see slight improvement of 1-3% due to bypassing the shifts and the instruction rearranging.
2012-08-21 19:20:55 +00:00
bge L(null)
lwzu r12,4(r8)
cmpb r10,r12,r4
addi r9,r8,4
cmplwi cr6,r10,0
powerpc: Various P7-optimized string functions
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cmplw r9,r7
[Powerpc] Tune/optimize powerpc{32,64}/power7/memchr.S. Assorted tweaking, twisting and tuning to squeeze a few additional cycles out of the memchr code. Changes include bypassing the shift pairs (sld,srd) when they are not required, and unrolling the small_loop that handles short and trailing strings. Per scrollpipe data measuring aligned strings for 64-bit, these changes save between five and eight cycles (9-13% overall) for short strings (<32), Longer aligned strings see slight improvement of 1-3% due to bypassing the shifts and the instruction rearranging.
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bne cr6,L(done)
powerpc: Various P7-optimized string functions
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bge L(null)
[Powerpc] Tune/optimize powerpc{32,64}/power7/memchr.S. Assorted tweaking, twisting and tuning to squeeze a few additional cycles out of the memchr code. Changes include bypassing the shift pairs (sld,srd) when they are not required, and unrolling the small_loop that handles short and trailing strings. Per scrollpipe data measuring aligned strings for 64-bit, these changes save between five and eight cycles (9-13% overall) for short strings (<32), Longer aligned strings see slight improvement of 1-3% due to bypassing the shifts and the instruction rearranging.
2012-08-21 19:20:55 +00:00
lwzu r12,4(r8)
cmpb r10,r12,r4
addi r9,r8,4
cmplwi cr6,r10,0
cmplw r9,r7
bne cr6,L(done)
bge L(null)
lwzu r12,4(r8)
cmpb r10,r12,r4
addi r9,r8,4
cmplwi cr6,r10,0
cmplw r9,r7
bne cr6,L(done)
bge L(null)
/* For most cases we will never get here. Under some combinations of
padding + length there is a leftover word that still needs to be
checked. */
lwzu r12,4(r8)
cmpb r10,r12,r4
addi r9,r8,4
cmplwi cr6,r10,0
bne cr6,L(done)
/* save a branch and exit directly */
li r3,0
blr
powerpc: Various P7-optimized string functions
2010-08-19 14:38:41 +00:00
Remove powerpc32 bounded-pointers code.
2013-02-28 21:23:47 +00:00
END (__memchr)
weak_alias (__memchr, memchr)
powerpc: Various P7-optimized string functions
2010-08-19 14:38:41 +00:00
libc_hidden_builtin_def (memchr)
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