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glibc/sysdeps/mips/memcpy.S
Steve Ellcey 8a71d2e27f Fix MIPS64 memcpy regression. 
The MIPS memcpy optimizations at
<https://sourceware.org/ml/libc-alpha/2015-10/msg00597.html>
introduced a bug causing many string function tests to fail with
segfaults for n32 and n64:

FAIL: string/stratcliff
FAIL: string/test-bcopy
FAIL: string/test-memccpy
FAIL: string/test-memcmp
FAIL: string/test-memcpy
FAIL: string/test-memmove
FAIL: string/test-mempcpy
FAIL: string/test-stpncpy
FAIL: string/test-strncmp
FAIL: string/test-strncpy

(Some failures in other directories could also be caused by this bug.)

The problem is that after the check for whether a word of input is
left that can be copied as a word before moving to byte copies, a load
can occur in the branch delay slot, resulting in a segfault if we are
at the end of a page and the following page is unmapped.  I don't see
how this would have passed the tests as reported in the original patch
posting (different kernel configurations affecting the code setting up
unmapped pages, maybe?), since the tests in question don't appear to
have changed recently.

This patch moves a later instruction into the delay slot, as suggested
at <https://sourceware.org/ml/libc-alpha/2016-01/msg00584.html>.

Tested for n32 and n64.

2016-01-28  Steve Ellcey  <sellcey@imgtec.com>
            Joseph Myers  <joseph@codesourcery.com>

	* sysdeps/mips/memcpy.S (MEMCPY_NAME) [USE_DOUBLE]: Avoid word
	load in branch delay slot when less than a word of input left.
2016-01-28 01:52:05 +00:00

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/* Copyright (C) 2012-2016 Free Software Foundation, Inc.
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, see
<http://www.gnu.org/licenses/>. */
#ifdef ANDROID_CHANGES
# include "machine/asm.h"
# include "machine/regdef.h"
# define USE_MEMMOVE_FOR_OVERLAP
# define PREFETCH_LOAD_HINT PREFETCH_HINT_LOAD_STREAMED
# define PREFETCH_STORE_HINT PREFETCH_HINT_PREPAREFORSTORE
#elif _LIBC
# include <sysdep.h>
# include <regdef.h>
# include <sys/asm.h>
# define PREFETCH_LOAD_HINT PREFETCH_HINT_LOAD_STREAMED
# define PREFETCH_STORE_HINT PREFETCH_HINT_PREPAREFORSTORE
#elif defined _COMPILING_NEWLIB
# include "machine/asm.h"
# include "machine/regdef.h"
# define PREFETCH_LOAD_HINT PREFETCH_HINT_LOAD_STREAMED
# define PREFETCH_STORE_HINT PREFETCH_HINT_PREPAREFORSTORE
#else
# include <regdef.h>
# include <sys/asm.h>
#endif
#if (_MIPS_ISA == _MIPS_ISA_MIPS4) || (_MIPS_ISA == _MIPS_ISA_MIPS5) || \
(_MIPS_ISA == _MIPS_ISA_MIPS32) || (_MIPS_ISA == _MIPS_ISA_MIPS64)
# ifndef DISABLE_PREFETCH
# define USE_PREFETCH
# endif
#endif
#if defined(_MIPS_SIM) && ((_MIPS_SIM == _ABI64) || (_MIPS_SIM == _ABIN32))
# ifndef DISABLE_DOUBLE
# define USE_DOUBLE
# endif
#endif
/* Some asm.h files do not have the L macro definition. */
#ifndef L
# if _MIPS_SIM == _ABIO32
# define L(label) $L ## label
# else
# define L(label) .L ## label
# endif
#endif
/* Some asm.h files do not have the PTR_ADDIU macro definition. */
#ifndef PTR_ADDIU
# ifdef USE_DOUBLE
# define PTR_ADDIU daddiu
# else
# define PTR_ADDIU addiu
# endif
#endif
/* Some asm.h files do not have the PTR_SRA macro definition. */
#ifndef PTR_SRA
# ifdef USE_DOUBLE
# define PTR_SRA dsra
# else
# define PTR_SRA sra
# endif
#endif
/* New R6 instructions that may not be in asm.h. */
#ifndef PTR_LSA
# if _MIPS_SIM == _ABI64
# define PTR_LSA dlsa
# else
# define PTR_LSA lsa
# endif
#endif
/*
* Using PREFETCH_HINT_LOAD_STREAMED instead of PREFETCH_LOAD on load
* prefetches appears to offer a slight preformance advantage.
*
* Using PREFETCH_HINT_PREPAREFORSTORE instead of PREFETCH_STORE
* or PREFETCH_STORE_STREAMED offers a large performance advantage
* but PREPAREFORSTORE has some special restrictions to consider.
*
* Prefetch with the 'prepare for store' hint does not copy a memory
* location into the cache, it just allocates a cache line and zeros
* it out. This means that if you do not write to the entire cache
* line before writing it out to memory some data will get zero'ed out
* when the cache line is written back to memory and data will be lost.
*
* Also if you are using this memcpy to copy overlapping buffers it may
* not behave correctly when using the 'prepare for store' hint. If you
* use the 'prepare for store' prefetch on a memory area that is in the
* memcpy source (as well as the memcpy destination), then you will get
* some data zero'ed out before you have a chance to read it and data will
* be lost.
*
* If you are going to use this memcpy routine with the 'prepare for store'
* prefetch you may want to set USE_MEMMOVE_FOR_OVERLAP in order to avoid
* the problem of running memcpy on overlapping buffers.
*
* There are ifdef'ed sections of this memcpy to make sure that it does not
* do prefetches on cache lines that are not going to be completely written.
* This code is only needed and only used when PREFETCH_STORE_HINT is set to
* PREFETCH_HINT_PREPAREFORSTORE. This code assumes that cache lines are
* 32 bytes and if the cache line is larger it will not work correctly.
*/
#ifdef USE_PREFETCH
# define PREFETCH_HINT_LOAD 0
# define PREFETCH_HINT_STORE 1
# define PREFETCH_HINT_LOAD_STREAMED 4
# define PREFETCH_HINT_STORE_STREAMED 5
# define PREFETCH_HINT_LOAD_RETAINED 6
# define PREFETCH_HINT_STORE_RETAINED 7
# define PREFETCH_HINT_WRITEBACK_INVAL 25
# define PREFETCH_HINT_PREPAREFORSTORE 30
/*
* If we have not picked out what hints to use at this point use the
* standard load and store prefetch hints.
*/
# ifndef PREFETCH_STORE_HINT
# define PREFETCH_STORE_HINT PREFETCH_HINT_STORE
# endif
# ifndef PREFETCH_LOAD_HINT
# define PREFETCH_LOAD_HINT PREFETCH_HINT_LOAD
# endif
/*
* We double everything when USE_DOUBLE is true so we do 2 prefetches to
* get 64 bytes in that case. The assumption is that each individual
* prefetch brings in 32 bytes.
*/
# ifdef USE_DOUBLE
# define PREFETCH_CHUNK 64
# define PREFETCH_FOR_LOAD(chunk, reg) \
pref PREFETCH_LOAD_HINT, (chunk)*64(reg); \
pref PREFETCH_LOAD_HINT, ((chunk)*64)+32(reg)
# define PREFETCH_FOR_STORE(chunk, reg) \
pref PREFETCH_STORE_HINT, (chunk)*64(reg); \
pref PREFETCH_STORE_HINT, ((chunk)*64)+32(reg)
# else
# define PREFETCH_CHUNK 32
# define PREFETCH_FOR_LOAD(chunk, reg) \
pref PREFETCH_LOAD_HINT, (chunk)*32(reg)
# define PREFETCH_FOR_STORE(chunk, reg) \
pref PREFETCH_STORE_HINT, (chunk)*32(reg)
# endif
/* MAX_PREFETCH_SIZE is the maximum size of a prefetch, it must not be less
* than PREFETCH_CHUNK, the assumed size of each prefetch. If the real size
* of a prefetch is greater than MAX_PREFETCH_SIZE and the PREPAREFORSTORE
* hint is used, the code will not work correctly. If PREPAREFORSTORE is not
* used then MAX_PREFETCH_SIZE does not matter. */
# define MAX_PREFETCH_SIZE 128
/* PREFETCH_LIMIT is set based on the fact that we never use an offset greater
* than 5 on a STORE prefetch and that a single prefetch can never be larger
* than MAX_PREFETCH_SIZE. We add the extra 32 when USE_DOUBLE is set because
* we actually do two prefetches in that case, one 32 bytes after the other. */
# ifdef USE_DOUBLE
# define PREFETCH_LIMIT (5 * PREFETCH_CHUNK) + 32 + MAX_PREFETCH_SIZE
# else
# define PREFETCH_LIMIT (5 * PREFETCH_CHUNK) + MAX_PREFETCH_SIZE
# endif
# if (PREFETCH_STORE_HINT == PREFETCH_HINT_PREPAREFORSTORE) \
&& ((PREFETCH_CHUNK * 4) < MAX_PREFETCH_SIZE)
/* We cannot handle this because the initial prefetches may fetch bytes that
* are before the buffer being copied. We start copies with an offset
* of 4 so avoid this situation when using PREPAREFORSTORE. */
#error "PREFETCH_CHUNK is too large and/or MAX_PREFETCH_SIZE is too small."
# endif
#else /* USE_PREFETCH not defined */
# define PREFETCH_FOR_LOAD(offset, reg)
# define PREFETCH_FOR_STORE(offset, reg)
#endif
#if __mips_isa_rev > 5
# if (PREFETCH_STORE_HINT == PREFETCH_HINT_PREPAREFORSTORE)
# undef PREFETCH_STORE_HINT
# define PREFETCH_STORE_HINT PREFETCH_HINT_STORE_STREAMED
# endif
# define R6_CODE
#endif
/* Allow the routine to be named something else if desired. */
#ifndef MEMCPY_NAME
# define MEMCPY_NAME memcpy
#endif
/* We use these 32/64 bit registers as temporaries to do the copying. */
#define REG0 t0
#define REG1 t1
#define REG2 t2
#define REG3 t3
#if defined(_MIPS_SIM) && ((_MIPS_SIM == _ABIO32) || (_MIPS_SIM == _ABIO64))
# define REG4 t4
# define REG5 t5
# define REG6 t6
# define REG7 t7
#else
# define REG4 ta0
# define REG5 ta1
# define REG6 ta2
# define REG7 ta3
#endif
/* We load/store 64 bits at a time when USE_DOUBLE is true.
* The C_ prefix stands for CHUNK and is used to avoid macro name
* conflicts with system header files. */
#ifdef USE_DOUBLE
# define C_ST sd
# define C_LD ld
# ifdef __MIPSEB
# define C_LDHI ldl /* high part is left in big-endian */
# define C_STHI sdl /* high part is left in big-endian */
# define C_LDLO ldr /* low part is right in big-endian */
# define C_STLO sdr /* low part is right in big-endian */
# else
# define C_LDHI ldr /* high part is right in little-endian */
# define C_STHI sdr /* high part is right in little-endian */
# define C_LDLO ldl /* low part is left in little-endian */
# define C_STLO sdl /* low part is left in little-endian */
# endif
# define C_ALIGN dalign /* r6 align instruction */
#else
# define C_ST sw
# define C_LD lw
# ifdef __MIPSEB
# define C_LDHI lwl /* high part is left in big-endian */
# define C_STHI swl /* high part is left in big-endian */
# define C_LDLO lwr /* low part is right in big-endian */
# define C_STLO swr /* low part is right in big-endian */
# else
# define C_LDHI lwr /* high part is right in little-endian */
# define C_STHI swr /* high part is right in little-endian */
# define C_LDLO lwl /* low part is left in little-endian */
# define C_STLO swl /* low part is left in little-endian */
# endif
# define C_ALIGN align /* r6 align instruction */
#endif
/* Bookkeeping values for 32 vs. 64 bit mode. */
#ifdef USE_DOUBLE
# define NSIZE 8
# define NSIZEMASK 0x3f
# define NSIZEDMASK 0x7f
#else
# define NSIZE 4
# define NSIZEMASK 0x1f
# define NSIZEDMASK 0x3f
#endif
#define UNIT(unit) ((unit)*NSIZE)
#define UNITM1(unit) (((unit)*NSIZE)-1)
#ifdef ANDROID_CHANGES
LEAF(MEMCPY_NAME, 0)
#else
LEAF(MEMCPY_NAME)
#endif
.set nomips16
.set noreorder
/*
* Below we handle the case where memcpy is called with overlapping src and dst.
* Although memcpy is not required to handle this case, some parts of Android
* like Skia rely on such usage. We call memmove to handle such cases.
*/
#ifdef USE_MEMMOVE_FOR_OVERLAP
PTR_SUBU t0,a0,a1
PTR_SRA t2,t0,31
xor t1,t0,t2
PTR_SUBU t0,t1,t2
sltu t2,t0,a2
beq t2,zero,L(memcpy)
la t9,memmove
jr t9
nop
L(memcpy):
#endif
/*
* If the size is less than 2*NSIZE (8 or 16), go to L(lastb). Regardless of
* size, copy dst pointer to v0 for the return value.
*/
slti t2,a2,(2 * NSIZE)
bne t2,zero,L(lasts)
#if defined(RETURN_FIRST_PREFETCH) || defined(RETURN_LAST_PREFETCH)
move v0,zero
#else
move v0,a0
#endif
#ifndef R6_CODE
/*
* If src and dst have different alignments, go to L(unaligned), if they
* have the same alignment (but are not actually aligned) do a partial
* load/store to make them aligned. If they are both already aligned
* we can start copying at L(aligned).
*/
xor t8,a1,a0
andi t8,t8,(NSIZE-1) /* t8 is a0/a1 word-displacement */
bne t8,zero,L(unaligned)
PTR_SUBU a3, zero, a0
andi a3,a3,(NSIZE-1) /* copy a3 bytes to align a0/a1 */
beq a3,zero,L(aligned) /* if a3=0, it is already aligned */
PTR_SUBU a2,a2,a3 /* a2 is the remining bytes count */
C_LDHI t8,0(a1)
PTR_ADDU a1,a1,a3
C_STHI t8,0(a0)
PTR_ADDU a0,a0,a3
#else /* R6_CODE */
/*
* Align the destination and hope that the source gets aligned too. If it
* doesn't we jump to L(r6_unaligned*) to do unaligned copies using the r6
* align instruction.
*/
andi t8,a0,7
lapc t9,L(atable)
PTR_LSA t9,t8,t9,2
jrc t9
L(atable):
bc L(lb0)
bc L(lb7)
bc L(lb6)
bc L(lb5)
bc L(lb4)
bc L(lb3)
bc L(lb2)
bc L(lb1)
L(lb7):
lb a3, 6(a1)
sb a3, 6(a0)
L(lb6):
lb a3, 5(a1)
sb a3, 5(a0)
L(lb5):
lb a3, 4(a1)
sb a3, 4(a0)
L(lb4):
lb a3, 3(a1)
sb a3, 3(a0)
L(lb3):
lb a3, 2(a1)
sb a3, 2(a0)
L(lb2):
lb a3, 1(a1)
sb a3, 1(a0)
L(lb1):
lb a3, 0(a1)
sb a3, 0(a0)
li t9,8
subu t8,t9,t8
PTR_SUBU a2,a2,t8
PTR_ADDU a0,a0,t8
PTR_ADDU a1,a1,t8
L(lb0):
andi t8,a1,(NSIZE-1)
lapc t9,L(jtable)
PTR_LSA t9,t8,t9,2
jrc t9
L(jtable):
bc L(aligned)
bc L(r6_unaligned1)
bc L(r6_unaligned2)
bc L(r6_unaligned3)
# ifdef USE_DOUBLE
bc L(r6_unaligned4)
bc L(r6_unaligned5)
bc L(r6_unaligned6)
bc L(r6_unaligned7)
# endif
#endif /* R6_CODE */
L(aligned):
/*
* Now dst/src are both aligned to (word or double word) aligned addresses
* Set a2 to count how many bytes we have to copy after all the 64/128 byte
* chunks are copied and a3 to the dst pointer after all the 64/128 byte
* chunks have been copied. We will loop, incrementing a0 and a1 until a0
* equals a3.
*/
andi t8,a2,NSIZEDMASK /* any whole 64-byte/128-byte chunks? */
beq a2,t8,L(chkw) /* if a2==t8, no 64-byte/128-byte chunks */
PTR_SUBU a3,a2,t8 /* subtract from a2 the reminder */
PTR_ADDU a3,a0,a3 /* Now a3 is the final dst after loop */
/* When in the loop we may prefetch with the 'prepare to store' hint,
* in this case the a0+x should not be past the "t0-32" address. This
* means: for x=128 the last "safe" a0 address is "t0-160". Alternatively,
* for x=64 the last "safe" a0 address is "t0-96" In the current version we
* will use "prefetch hint,128(a0)", so "t0-160" is the limit.
*/
#if defined(USE_PREFETCH) && (PREFETCH_STORE_HINT == PREFETCH_HINT_PREPAREFORSTORE)
PTR_ADDU t0,a0,a2 /* t0 is the "past the end" address */
PTR_SUBU t9,t0,PREFETCH_LIMIT /* t9 is the "last safe pref" address */
#endif
PREFETCH_FOR_LOAD (0, a1)
PREFETCH_FOR_LOAD (1, a1)
PREFETCH_FOR_LOAD (2, a1)
PREFETCH_FOR_LOAD (3, a1)
#if defined(USE_PREFETCH) && (PREFETCH_STORE_HINT != PREFETCH_HINT_PREPAREFORSTORE)
PREFETCH_FOR_STORE (1, a0)
PREFETCH_FOR_STORE (2, a0)
PREFETCH_FOR_STORE (3, a0)
#endif
#if defined(RETURN_FIRST_PREFETCH) && defined(USE_PREFETCH)
# if PREFETCH_STORE_HINT == PREFETCH_HINT_PREPAREFORSTORE
sltu v1,t9,a0
bgtz v1,L(skip_set)
nop
PTR_ADDIU v0,a0,(PREFETCH_CHUNK*4)
L(skip_set):
# else
PTR_ADDIU v0,a0,(PREFETCH_CHUNK*1)
# endif
#endif
#if defined(RETURN_LAST_PREFETCH) && defined(USE_PREFETCH) \
&& (PREFETCH_STORE_HINT != PREFETCH_HINT_PREPAREFORSTORE)
PTR_ADDIU v0,a0,(PREFETCH_CHUNK*3)
# ifdef USE_DOUBLE
PTR_ADDIU v0,v0,32
# endif
#endif
L(loop16w):
C_LD t0,UNIT(0)(a1)
#if defined(USE_PREFETCH) && (PREFETCH_STORE_HINT == PREFETCH_HINT_PREPAREFORSTORE)
sltu v1,t9,a0 /* If a0 > t9 don't use next prefetch */
bgtz v1,L(skip_pref)
#endif
C_LD t1,UNIT(1)(a1)
#ifdef R6_CODE
PREFETCH_FOR_STORE (2, a0)
#else
PREFETCH_FOR_STORE (4, a0)
PREFETCH_FOR_STORE (5, a0)
#endif
#if defined(RETURN_LAST_PREFETCH) && defined(USE_PREFETCH)
PTR_ADDIU v0,a0,(PREFETCH_CHUNK*5)
# ifdef USE_DOUBLE
PTR_ADDIU v0,v0,32
# endif
#endif
L(skip_pref):
C_LD REG2,UNIT(2)(a1)
C_LD REG3,UNIT(3)(a1)
C_LD REG4,UNIT(4)(a1)
C_LD REG5,UNIT(5)(a1)
C_LD REG6,UNIT(6)(a1)
C_LD REG7,UNIT(7)(a1)
#ifdef R6_CODE
PREFETCH_FOR_LOAD (3, a1)
#else
PREFETCH_FOR_LOAD (4, a1)
#endif
C_ST t0,UNIT(0)(a0)
C_ST t1,UNIT(1)(a0)
C_ST REG2,UNIT(2)(a0)
C_ST REG3,UNIT(3)(a0)
C_ST REG4,UNIT(4)(a0)
C_ST REG5,UNIT(5)(a0)
C_ST REG6,UNIT(6)(a0)
C_ST REG7,UNIT(7)(a0)
C_LD t0,UNIT(8)(a1)
C_LD t1,UNIT(9)(a1)
C_LD REG2,UNIT(10)(a1)
C_LD REG3,UNIT(11)(a1)
C_LD REG4,UNIT(12)(a1)
C_LD REG5,UNIT(13)(a1)
C_LD REG6,UNIT(14)(a1)
C_LD REG7,UNIT(15)(a1)
#ifndef R6_CODE
PREFETCH_FOR_LOAD (5, a1)
#endif
C_ST t0,UNIT(8)(a0)
C_ST t1,UNIT(9)(a0)
C_ST REG2,UNIT(10)(a0)
C_ST REG3,UNIT(11)(a0)
C_ST REG4,UNIT(12)(a0)
C_ST REG5,UNIT(13)(a0)
C_ST REG6,UNIT(14)(a0)
C_ST REG7,UNIT(15)(a0)
PTR_ADDIU a0,a0,UNIT(16) /* adding 64/128 to dest */
bne a0,a3,L(loop16w)
PTR_ADDIU a1,a1,UNIT(16) /* adding 64/128 to src */
move a2,t8
/* Here we have src and dest word-aligned but less than 64-bytes or
* 128 bytes to go. Check for a 32(64) byte chunk and copy if if there
* is one. Otherwise jump down to L(chk1w) to handle the tail end of
* the copy.
*/
L(chkw):
PREFETCH_FOR_LOAD (0, a1)
andi t8,a2,NSIZEMASK /* Is there a 32-byte/64-byte chunk. */
/* The t8 is the reminder count past 32-bytes */
beq a2,t8,L(chk1w) /* When a2=t8, no 32-byte chunk */
nop
C_LD t0,UNIT(0)(a1)
C_LD t1,UNIT(1)(a1)
C_LD REG2,UNIT(2)(a1)
C_LD REG3,UNIT(3)(a1)
C_LD REG4,UNIT(4)(a1)
C_LD REG5,UNIT(5)(a1)
C_LD REG6,UNIT(6)(a1)
C_LD REG7,UNIT(7)(a1)
PTR_ADDIU a1,a1,UNIT(8)
C_ST t0,UNIT(0)(a0)
C_ST t1,UNIT(1)(a0)
C_ST REG2,UNIT(2)(a0)
C_ST REG3,UNIT(3)(a0)
C_ST REG4,UNIT(4)(a0)
C_ST REG5,UNIT(5)(a0)
C_ST REG6,UNIT(6)(a0)
C_ST REG7,UNIT(7)(a0)
PTR_ADDIU a0,a0,UNIT(8)
/*
* Here we have less than 32(64) bytes to copy. Set up for a loop to
* copy one word (or double word) at a time. Set a2 to count how many
* bytes we have to copy after all the word (or double word) chunks are
* copied and a3 to the dst pointer after all the (d)word chunks have
* been copied. We will loop, incrementing a0 and a1 until a0 equals a3.
*/
L(chk1w):
andi a2,t8,(NSIZE-1) /* a2 is the reminder past one (d)word chunks */
beq a2,t8,L(lastw)
PTR_SUBU a3,t8,a2 /* a3 is count of bytes in one (d)word chunks */
PTR_ADDU a3,a0,a3 /* a3 is the dst address after loop */
/* copying in words (4-byte or 8-byte chunks) */
L(wordCopy_loop):
C_LD REG3,UNIT(0)(a1)
PTR_ADDIU a0,a0,UNIT(1)
PTR_ADDIU a1,a1,UNIT(1)
bne a0,a3,L(wordCopy_loop)
C_ST REG3,UNIT(-1)(a0)
/* If we have been copying double words, see if we can copy a single word
before doing byte copies. We can have, at most, one word to copy. */
L(lastw):
#ifdef USE_DOUBLE
andi t8,a2,3 /* a2 is the remainder past 4 byte chunks. */
beq t8,a2,L(lastb)
move a2,t8
lw REG3,0(a1)
sw REG3,0(a0)
PTR_ADDIU a0,a0,4
PTR_ADDIU a1,a1,4
#endif
/* Copy the last 8 (or 16) bytes */
L(lastb):
blez a2,L(leave)
PTR_ADDU a3,a0,a2 /* a3 is the last dst address */
L(lastbloop):
lb v1,0(a1)
PTR_ADDIU a0,a0,1
PTR_ADDIU a1,a1,1
bne a0,a3,L(lastbloop)
sb v1,-1(a0)
L(leave):
j ra
nop
/* We jump here with a memcpy of less than 8 or 16 bytes, depending on
whether or not USE_DOUBLE is defined. Instead of just doing byte
copies, check the alignment and size and use lw/sw if possible.
Otherwise, do byte copies. */
L(lasts):
andi t8,a2,3
beq t8,a2,L(lastb)
andi t9,a0,3
bne t9,zero,L(lastb)
andi t9,a1,3
bne t9,zero,L(lastb)
PTR_SUBU a3,a2,t8
PTR_ADDU a3,a0,a3
L(wcopy_loop):
lw REG3,0(a1)
PTR_ADDIU a0,a0,4
PTR_ADDIU a1,a1,4
bne a0,a3,L(wcopy_loop)
sw REG3,-4(a0)
b L(lastb)
move a2,t8
#ifndef R6_CODE
/*
* UNALIGNED case, got here with a3 = "negu a0"
* This code is nearly identical to the aligned code above
* but only the destination (not the source) gets aligned
* so we need to do partial loads of the source followed
* by normal stores to the destination (once we have aligned
* the destination).
*/
L(unaligned):
andi a3,a3,(NSIZE-1) /* copy a3 bytes to align a0/a1 */
beqz a3,L(ua_chk16w) /* if a3=0, it is already aligned */
PTR_SUBU a2,a2,a3 /* a2 is the remining bytes count */
C_LDHI v1,UNIT(0)(a1)
C_LDLO v1,UNITM1(1)(a1)
PTR_ADDU a1,a1,a3
C_STHI v1,UNIT(0)(a0)
PTR_ADDU a0,a0,a3
/*
* Now the destination (but not the source) is aligned
* Set a2 to count how many bytes we have to copy after all the 64/128 byte
* chunks are copied and a3 to the dst pointer after all the 64/128 byte
* chunks have been copied. We will loop, incrementing a0 and a1 until a0
* equals a3.
*/
L(ua_chk16w):
andi t8,a2,NSIZEDMASK /* any whole 64-byte/128-byte chunks? */
beq a2,t8,L(ua_chkw) /* if a2==t8, no 64-byte/128-byte chunks */
PTR_SUBU a3,a2,t8 /* subtract from a2 the reminder */
PTR_ADDU a3,a0,a3 /* Now a3 is the final dst after loop */
# if defined(USE_PREFETCH) && (PREFETCH_STORE_HINT == PREFETCH_HINT_PREPAREFORSTORE)
PTR_ADDU t0,a0,a2 /* t0 is the "past the end" address */
PTR_SUBU t9,t0,PREFETCH_LIMIT /* t9 is the "last safe pref" address */
# endif
PREFETCH_FOR_LOAD (0, a1)
PREFETCH_FOR_LOAD (1, a1)
PREFETCH_FOR_LOAD (2, a1)
# if defined(USE_PREFETCH) && (PREFETCH_STORE_HINT != PREFETCH_HINT_PREPAREFORSTORE)
PREFETCH_FOR_STORE (1, a0)
PREFETCH_FOR_STORE (2, a0)
PREFETCH_FOR_STORE (3, a0)
# endif
# if defined(RETURN_FIRST_PREFETCH) && defined(USE_PREFETCH)
# if (PREFETCH_STORE_HINT == PREFETCH_HINT_PREPAREFORSTORE)
sltu v1,t9,a0
bgtz v1,L(ua_skip_set)
nop
PTR_ADDIU v0,a0,(PREFETCH_CHUNK*4)
L(ua_skip_set):
# else
PTR_ADDIU v0,a0,(PREFETCH_CHUNK*1)
# endif
# endif
L(ua_loop16w):
PREFETCH_FOR_LOAD (3, a1)
C_LDHI t0,UNIT(0)(a1)
C_LDHI t1,UNIT(1)(a1)
C_LDHI REG2,UNIT(2)(a1)
# if defined(USE_PREFETCH) && (PREFETCH_STORE_HINT == PREFETCH_HINT_PREPAREFORSTORE)
sltu v1,t9,a0
bgtz v1,L(ua_skip_pref)
# endif
C_LDHI REG3,UNIT(3)(a1)
PREFETCH_FOR_STORE (4, a0)
PREFETCH_FOR_STORE (5, a0)
L(ua_skip_pref):
C_LDHI REG4,UNIT(4)(a1)
C_LDHI REG5,UNIT(5)(a1)
C_LDHI REG6,UNIT(6)(a1)
C_LDHI REG7,UNIT(7)(a1)
C_LDLO t0,UNITM1(1)(a1)
C_LDLO t1,UNITM1(2)(a1)
C_LDLO REG2,UNITM1(3)(a1)
C_LDLO REG3,UNITM1(4)(a1)
C_LDLO REG4,UNITM1(5)(a1)
C_LDLO REG5,UNITM1(6)(a1)
C_LDLO REG6,UNITM1(7)(a1)
C_LDLO REG7,UNITM1(8)(a1)
PREFETCH_FOR_LOAD (4, a1)
C_ST t0,UNIT(0)(a0)
C_ST t1,UNIT(1)(a0)
C_ST REG2,UNIT(2)(a0)
C_ST REG3,UNIT(3)(a0)
C_ST REG4,UNIT(4)(a0)
C_ST REG5,UNIT(5)(a0)
C_ST REG6,UNIT(6)(a0)
C_ST REG7,UNIT(7)(a0)
C_LDHI t0,UNIT(8)(a1)
C_LDHI t1,UNIT(9)(a1)
C_LDHI REG2,UNIT(10)(a1)
C_LDHI REG3,UNIT(11)(a1)
C_LDHI REG4,UNIT(12)(a1)
C_LDHI REG5,UNIT(13)(a1)
C_LDHI REG6,UNIT(14)(a1)
C_LDHI REG7,UNIT(15)(a1)
C_LDLO t0,UNITM1(9)(a1)
C_LDLO t1,UNITM1(10)(a1)
C_LDLO REG2,UNITM1(11)(a1)
C_LDLO REG3,UNITM1(12)(a1)
C_LDLO REG4,UNITM1(13)(a1)
C_LDLO REG5,UNITM1(14)(a1)
C_LDLO REG6,UNITM1(15)(a1)
C_LDLO REG7,UNITM1(16)(a1)
PREFETCH_FOR_LOAD (5, a1)
C_ST t0,UNIT(8)(a0)
C_ST t1,UNIT(9)(a0)
C_ST REG2,UNIT(10)(a0)
C_ST REG3,UNIT(11)(a0)
C_ST REG4,UNIT(12)(a0)
C_ST REG5,UNIT(13)(a0)
C_ST REG6,UNIT(14)(a0)
C_ST REG7,UNIT(15)(a0)
PTR_ADDIU a0,a0,UNIT(16) /* adding 64/128 to dest */
bne a0,a3,L(ua_loop16w)
PTR_ADDIU a1,a1,UNIT(16) /* adding 64/128 to src */
move a2,t8
/* Here we have src and dest word-aligned but less than 64-bytes or
* 128 bytes to go. Check for a 32(64) byte chunk and copy if if there
* is one. Otherwise jump down to L(ua_chk1w) to handle the tail end of
* the copy. */
L(ua_chkw):
PREFETCH_FOR_LOAD (0, a1)
andi t8,a2,NSIZEMASK /* Is there a 32-byte/64-byte chunk. */
/* t8 is the reminder count past 32-bytes */
beq a2,t8,L(ua_chk1w) /* When a2=t8, no 32-byte chunk */
nop
C_LDHI t0,UNIT(0)(a1)
C_LDHI t1,UNIT(1)(a1)
C_LDHI REG2,UNIT(2)(a1)
C_LDHI REG3,UNIT(3)(a1)
C_LDHI REG4,UNIT(4)(a1)
C_LDHI REG5,UNIT(5)(a1)
C_LDHI REG6,UNIT(6)(a1)
C_LDHI REG7,UNIT(7)(a1)
C_LDLO t0,UNITM1(1)(a1)
C_LDLO t1,UNITM1(2)(a1)
C_LDLO REG2,UNITM1(3)(a1)
C_LDLO REG3,UNITM1(4)(a1)
C_LDLO REG4,UNITM1(5)(a1)
C_LDLO REG5,UNITM1(6)(a1)
C_LDLO REG6,UNITM1(7)(a1)
C_LDLO REG7,UNITM1(8)(a1)
PTR_ADDIU a1,a1,UNIT(8)
C_ST t0,UNIT(0)(a0)
C_ST t1,UNIT(1)(a0)
C_ST REG2,UNIT(2)(a0)
C_ST REG3,UNIT(3)(a0)
C_ST REG4,UNIT(4)(a0)
C_ST REG5,UNIT(5)(a0)
C_ST REG6,UNIT(6)(a0)
C_ST REG7,UNIT(7)(a0)
PTR_ADDIU a0,a0,UNIT(8)
/*
* Here we have less than 32(64) bytes to copy. Set up for a loop to
* copy one word (or double word) at a time.
*/
L(ua_chk1w):
andi a2,t8,(NSIZE-1) /* a2 is the reminder past one (d)word chunks */
beq a2,t8,L(ua_smallCopy)
PTR_SUBU a3,t8,a2 /* a3 is count of bytes in one (d)word chunks */
PTR_ADDU a3,a0,a3 /* a3 is the dst address after loop */
/* copying in words (4-byte or 8-byte chunks) */
L(ua_wordCopy_loop):
C_LDHI v1,UNIT(0)(a1)
C_LDLO v1,UNITM1(1)(a1)
PTR_ADDIU a0,a0,UNIT(1)
PTR_ADDIU a1,a1,UNIT(1)
bne a0,a3,L(ua_wordCopy_loop)
C_ST v1,UNIT(-1)(a0)
/* Copy the last 8 (or 16) bytes */
L(ua_smallCopy):
beqz a2,L(leave)
PTR_ADDU a3,a0,a2 /* a3 is the last dst address */
L(ua_smallCopy_loop):
lb v1,0(a1)
PTR_ADDIU a0,a0,1
PTR_ADDIU a1,a1,1
bne a0,a3,L(ua_smallCopy_loop)
sb v1,-1(a0)
j ra
nop
#else /* R6_CODE */
# ifdef __MIPSEB
# define SWAP_REGS(X,Y) X, Y
# define ALIGN_OFFSET(N) (N)
# else
# define SWAP_REGS(X,Y) Y, X
# define ALIGN_OFFSET(N) (NSIZE-N)
# endif
# define R6_UNALIGNED_WORD_COPY(BYTEOFFSET) \
andi REG7, a2, (NSIZE-1);/* REG7 is # of bytes to by bytes. */ \
beq REG7, a2, L(lastb); /* Check for bytes to copy by word */ \
PTR_SUBU a3, a2, REG7; /* a3 is number of bytes to be copied in */ \
/* (d)word chunks. */ \
move a2, REG7; /* a2 is # of bytes to copy byte by byte */ \
/* after word loop is finished. */ \
PTR_ADDU REG6, a0, a3; /* REG6 is the dst address after loop. */ \
PTR_SUBU REG2, a1, t8; /* REG2 is the aligned src address. */ \
PTR_ADDU a1, a1, a3; /* a1 is addr of source after word loop. */ \
C_LD t0, UNIT(0)(REG2); /* Load first part of source. */ \
L(r6_ua_wordcopy##BYTEOFFSET): \
C_LD t1, UNIT(1)(REG2); /* Load second part of source. */ \
C_ALIGN REG3, SWAP_REGS(t1,t0), ALIGN_OFFSET(BYTEOFFSET); \
PTR_ADDIU a0, a0, UNIT(1); /* Increment destination pointer. */ \
PTR_ADDIU REG2, REG2, UNIT(1); /* Increment aligned source pointer.*/ \
move t0, t1; /* Move second part of source to first. */ \
bne a0, REG6,L(r6_ua_wordcopy##BYTEOFFSET); \
C_ST REG3, UNIT(-1)(a0); \
j L(lastb); \
nop
/* We are generating R6 code, the destination is 4 byte aligned and
the source is not 4 byte aligned. t8 is 1, 2, or 3 depending on the
alignment of the source. */
L(r6_unaligned1):
R6_UNALIGNED_WORD_COPY(1)
L(r6_unaligned2):
R6_UNALIGNED_WORD_COPY(2)
L(r6_unaligned3):
R6_UNALIGNED_WORD_COPY(3)
# ifdef USE_DOUBLE
L(r6_unaligned4):
R6_UNALIGNED_WORD_COPY(4)
L(r6_unaligned5):
R6_UNALIGNED_WORD_COPY(5)
L(r6_unaligned6):
R6_UNALIGNED_WORD_COPY(6)
L(r6_unaligned7):
R6_UNALIGNED_WORD_COPY(7)
# endif
#endif /* R6_CODE */
.set at
.set reorder
END(MEMCPY_NAME)
#ifndef ANDROID_CHANGES
# ifdef _LIBC
libc_hidden_builtin_def (MEMCPY_NAME)
# endif
#endif
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