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Diffstat (limited to 'sysdeps/mips/memset.S')
| -rw-r--r-- | sysdeps/mips/memset.S | 367 |
1 files changed, 367 insertions, 0 deletions
diff --git a/sysdeps/mips/memset.S b/sysdeps/mips/memset.S new file mode 100644 index 0000000000..999148095e --- /dev/null +++ b/sysdeps/mips/memset.S @@ -0,0 +1,367 @@ +/* Copyright (C) 2013-2014 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 PREFETCH_STORE_HINT PREFETCH_HINT_PREPAREFORSTORE +#elif _LIBC +# include <sysdep.h> +# include <regdef.h> +# include <sys/asm.h> +# define PREFETCH_STORE_HINT PREFETCH_HINT_PREPAREFORSTORE +#elif _COMPILING_NEWLIB +# include "machine/asm.h" +# include "machine/regdef.h" +# define PREFETCH_STORE_HINT PREFETCH_HINT_PREPAREFORSTORE +#else +# include <regdef.h> +# include <sys/asm.h> +#endif + +/* Check to see if the MIPS architecture we are compiling for supports + prefetching. */ + +#if (__mips == 4) || (__mips == 5) || (__mips == 32) || (__mips == 64) +# 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 + +#ifndef USE_DOUBLE +# ifndef DISABLE_DOUBLE_ALIGN +# define DOUBLE_ALIGN +# 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 + +/* 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. + + 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 + less than MAX_PREFETCH_SIZE bytes and if the cache line is larger it will + not work correctly. */ + +#ifdef USE_PREFETCH +# define PREFETCH_HINT_STORE 1 +# define PREFETCH_HINT_STORE_STREAMED 5 +# define PREFETCH_HINT_STORE_RETAINED 7 +# 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 + +/* 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_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_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 than 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_STORE(offset, reg) +#endif + +/* Allow the routine to be named something else if desired. */ +#ifndef MEMSET_NAME +# define MEMSET_NAME memset +#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 +# if __MIPSEB +# define C_STHI sdl /* high part is left in big-endian */ +# else +# define C_STHI sdr /* high part is right in little-endian */ +# endif +#else +# define C_ST sw +# if __MIPSEB +# define C_STHI swl /* high part is left in big-endian */ +# else +# define C_STHI swr /* high part is right in little-endian */ +# endif +#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(MEMSET_NAME,0) +#else +LEAF(MEMSET_NAME) +#endif + + .set nomips16 + .set noreorder +/* 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(lastb) + move v0,a0 + +/* If memset value is not zero, we copy it to all the bytes in a 32 or 64 + bit word. */ + beq a1,zero,L(set0) /* If memset value is zero no smear */ + PTR_SUBU a3,zero,a0 + nop + + /* smear byte into 32 or 64 bit word */ +#if ((__mips == 64) || (__mips == 32)) && (__mips_isa_rev >= 2) +# ifdef USE_DOUBLE + dins a1, a1, 8, 8 /* Replicate fill byte into half-word. */ + dins a1, a1, 16, 16 /* Replicate fill byte into word. */ + dins a1, a1, 32, 32 /* Replicate fill byte into dbl word. */ +# else + ins a1, a1, 8, 8 /* Replicate fill byte into half-word. */ + ins a1, a1, 16, 16 /* Replicate fill byte into word. */ +# endif +#else +# ifdef USE_DOUBLE + and a1,0xff + dsll t2,a1,8 + or a1,t2 + dsll t2,a1,16 + or a1,t2 + dsll t2,a1,32 + or a1,t2 +# else + and a1,0xff + sll t2,a1,8 + or a1,t2 + sll t2,a1,16 + or a1,t2 +# endif +#endif + +/* If the destination address is not aligned do a partial store to get it + aligned. If it is already aligned just jump to L(aligned). */ +L(set0): + andi t2,a3,(NSIZE-1) /* word-unaligned address? */ + beq t2,zero,L(aligned) /* t2 is the unalignment count */ + PTR_SUBU a2,a2,t2 + C_STHI a1,0(a0) + PTR_ADDU a0,a0,t2 + +L(aligned): +/* If USE_DOUBLE is not set we may still want to align the data on a 16 + byte boundry instead of an 8 byte boundry to maximize the opportunity + of proAptiv chips to do memory bonding (combining two sequential 4 + byte stores into one 8 byte store). We know there are at least 4 bytes + left to store or we would have jumped to L(lastb) earlier in the code. */ +#ifdef DOUBLE_ALIGN + andi t2,a3,4 + beq t2,zero,L(double_aligned) + PTR_SUBU a2,a2,t2 + sw a1,0(a0) + PTR_ADDU a0,a0,t2 +L(double_aligned): +#endif + +/* Now the destination is aligned to (word or double word) aligned address + Set a2 to count how many bytes we have to copy after all the 64/128 byte + chunks are copied and a3 to the dest pointer after all the 64/128 byte + chunks have been copied. We will loop, incrementing a0 until it 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 +#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 + +L(loop16w): +#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) + nop +#endif + PREFETCH_FOR_STORE (4, a0) + PREFETCH_FOR_STORE (5, a0) +L(skip_pref): + C_ST a1,UNIT(0)(a0) + C_ST a1,UNIT(1)(a0) + C_ST a1,UNIT(2)(a0) + C_ST a1,UNIT(3)(a0) + C_ST a1,UNIT(4)(a0) + C_ST a1,UNIT(5)(a0) + C_ST a1,UNIT(6)(a0) + C_ST a1,UNIT(7)(a0) + C_ST a1,UNIT(8)(a0) + C_ST a1,UNIT(9)(a0) + C_ST a1,UNIT(10)(a0) + C_ST a1,UNIT(11)(a0) + C_ST a1,UNIT(12)(a0) + C_ST a1,UNIT(13)(a0) + C_ST a1,UNIT(14)(a0) + C_ST a1,UNIT(15)(a0) + PTR_ADDIU a0,a0,UNIT(16) /* adding 64/128 to dest */ + bne a0,a3,L(loop16w) + nop + move a2,t8 + +/* Here we have 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): + 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_ST a1,UNIT(0)(a0) + C_ST a1,UNIT(1)(a0) + C_ST a1,UNIT(2)(a0) + C_ST a1,UNIT(3)(a0) + C_ST a1,UNIT(4)(a0) + C_ST a1,UNIT(5)(a0) + C_ST a1,UNIT(6)(a0) + C_ST a1,UNIT(7)(a0) + PTR_ADDIU a0,a0,UNIT(8) + +/* Here we have less than 32(64) bytes to set. 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 dest pointer after all the (d)word chunks have + been copied. We will loop, incrementing a0 until a0 equals a3. */ +L(chk1w): + andi a2,t8,(NSIZE-1) /* a2 is the reminder past one (d)word chunks */ + beq a2,t8,L(lastb) + 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): + PTR_ADDIU a0,a0,UNIT(1) + bne a0,a3,L(wordCopy_loop) + C_ST a1,UNIT(-1)(a0) + +/* 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): + PTR_ADDIU a0,a0,1 + bne a0,a3,L(lastbloop) + sb a1,-1(a0) +L(leave): + j ra + nop + + .set at + .set reorder +END(MEMSET_NAME) +#ifndef ANDROID_CHANGES +# ifdef _LIBC +libc_hidden_builtin_def (MEMSET_NAME) +# endif +#endif |