/* Optimized 32-bit memset implementation for POWER6. Copyright (C) 1997-2013 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 . */ #include #include #include /* __ptr_t [r3] memset (__ptr_t s [r3], int c [r4], size_t n [r5])); Returns 's'. The memset is done in three sizes: byte (8 bits), word (32 bits), cache line (1024 bits). There is a special case for setting cache lines to 0, to take advantage of the dcbz instruction. */ .machine power6 EALIGN (BP_SYM (memset), 7, 0) CALL_MCOUNT #define rTMP r0 #define rRTN r3 /* Initial value of 1st argument. */ #define rMEMP0 r3 /* Original value of 1st arg. */ #define rCHR r4 /* Char to set in each byte. */ #define rLEN r5 /* Length of region to set. */ #define rMEMP r6 /* Address at which we are storing. */ #define rALIGN r7 /* Number of bytes we are setting now (when aligning). */ #define rMEMP2 r8 #define rNEG64 r8 /* Constant -64 for clearing with dcbz. */ #define rMEMP3 r9 /* Alt mem pointer. */ L(_memset): /* Take care of case for size <= 4. */ cmplwi cr1, rLEN, 4 andi. rALIGN, rMEMP0, 3 mr rMEMP, rMEMP0 ble- cr1, L(small) /* Align to word boundary. */ cmplwi cr5, rLEN, 31 rlwimi rCHR, rCHR, 8, 16, 23 /* Replicate byte to halfword. */ beq+ L(aligned) mtcrf 0x01, rMEMP0 subfic rALIGN, rALIGN, 4 add rMEMP, rMEMP, rALIGN sub rLEN, rLEN, rALIGN bf+ 31, L(g0) stb rCHR, 0(rMEMP0) bt 30, L(aligned) L(g0): sth rCHR, -2(rMEMP) .align 4 /* Handle the case of size < 31. */ L(aligned): mtcrf 0x01, rLEN rlwimi rCHR, rCHR, 16, 0, 15 /* Replicate halfword to word. */ ble cr5, L(medium) /* Align to 32-byte boundary. */ andi. rALIGN, rMEMP, 0x1C subfic rALIGN, rALIGN, 0x20 beq L(caligned) mtcrf 0x01, rALIGN add rMEMP, rMEMP, rALIGN sub rLEN, rLEN, rALIGN cmplwi cr1, rALIGN, 0x10 mr rMEMP2, rMEMP bf 28, L(a1) stw rCHR, -4(rMEMP2) stwu rCHR, -8(rMEMP2) nop L(a1): blt cr1, L(a2) stw rCHR, -4(rMEMP2) stw rCHR, -8(rMEMP2) stw rCHR, -12(rMEMP2) stwu rCHR, -16(rMEMP2) L(a2): bf 29, L(caligned) stw rCHR, -4(rMEMP2) .align 3 /* Now aligned to a 32 byte boundary. */ L(caligned): cmplwi cr1, rCHR, 0 clrrwi. rALIGN, rLEN, 5 mtcrf 0x01, rLEN beq cr1, L(zloopstart) /* Special case for clearing memory using dcbz. */ L(nondcbz): beq L(medium) /* We may not actually get to do a full line. */ nop /* Storing a non-zero "c" value. We are aligned at a sector (32-byte) boundary may not be at cache line (128-byte) boundary. */ L(nzloopstart): /* memset in 32-byte chunks until we get to a cache line boundary. If rLEN is less then the distance to the next cache-line boundary use cacheAligned1 code to finish the tail. */ cmplwi cr1,rLEN,128 andi. rTMP,rMEMP,127 blt cr1,L(cacheAligned1) addi rMEMP3,rMEMP,32 beq L(nzCacheAligned) addi rLEN,rLEN,-32 stw rCHR,0(rMEMP) stw rCHR,4(rMEMP) stw rCHR,8(rMEMP) stw rCHR,12(rMEMP) stw rCHR,16(rMEMP) stw rCHR,20(rMEMP) addi rMEMP,rMEMP,32 andi. rTMP,rMEMP3,127 stw rCHR,-8(rMEMP3) stw rCHR,-4(rMEMP3) beq L(nzCacheAligned) addi rLEN,rLEN,-32 stw rCHR,0(rMEMP3) stw rCHR,4(rMEMP3) addi rMEMP,rMEMP,32 stw rCHR,8(rMEMP3) stw rCHR,12(rMEMP3) andi. rTMP,rMEMP,127 stw rCHR,16(rMEMP3) stw rCHR,20(rMEMP3) stw rCHR,24(rMEMP3) stw rCHR,28(rMEMP3) beq L(nzCacheAligned) addi rLEN,rLEN,-32 /* At this point we can overrun the store queue (pipe reject) so it is time to slow things down. The store queue can merge two adjacent stores into a single L1/L2 op, but the L2 is clocked at 1/2 the CPU. So we add "group ending nops" to guarantee that we dispatch only two stores every other cycle. */ ori r1,r1,0 ori r1,r1,0 stw rCHR,32(rMEMP3) stw rCHR,36(rMEMP3) addi rMEMP,rMEMP,32 cmplwi cr1,rLEN,128 ori r1,r1,0 ori r1,r1,0 stw rCHR,40(rMEMP3) stw rCHR,44(rMEMP3) ori r1,r1,0 ori r1,r1,0 stw rCHR,48(rMEMP3) stw rCHR,52(rMEMP3) ori r1,r1,0 ori r1,r1,0 stw rCHR,56(rMEMP3) stw rCHR,60(rMEMP3) blt cr1,L(cacheAligned1) b L(nzCacheAligned) /* Now we are aligned to the cache line and can use dcbtst. */ .align 5 L(nzCacheAligned): cmplwi cr1,rLEN,128 cmplwi cr6,rLEN,256 blt cr1,L(cacheAligned1) blt cr6,L(nzCacheAligned128) .align 4 L(nzCacheAligned128): nop addi rMEMP3,rMEMP,64 stw rCHR,0(rMEMP) stw rCHR,4(rMEMP) stw rCHR,8(rMEMP) stw rCHR,12(rMEMP) stw rCHR,16(rMEMP) stw rCHR,20(rMEMP) stw rCHR,24(rMEMP) stw rCHR,28(rMEMP) stw rCHR,32(rMEMP) stw rCHR,36(rMEMP) stw rCHR,40(rMEMP) stw rCHR,44(rMEMP) stw rCHR,48(rMEMP) stw rCHR,52(rMEMP) stw rCHR,56(rMEMP) stw rCHR,60(rMEMP) addi rMEMP,rMEMP3,64 addi rLEN,rLEN,-128 /* At this point we can overrun the store queue (pipe reject) so it is time to slow things down. The store queue can merge two adjacent stores into a single L1/L2 op, but the L2 is clocked at 1/2 the CPU. So we add "group ending nops" to guarantee that we dispatch only one store per cycle. */ stw rCHR,0(rMEMP3) ori r1,r1,0 stw rCHR,4(rMEMP3) ori r1,r1,0 stw rCHR,8(rMEMP3) ori r1,r1,0 stw rCHR,12(rMEMP3) ori r1,r1,0 stw rCHR,16(rMEMP3) ori r1,r1,0 stw rCHR,20(rMEMP3) ori r1,r1,0 stw rCHR,24(rMEMP3) ori r1,r1,0 stw rCHR,28(rMEMP3) ori r1,r1,0 stw rCHR,32(rMEMP3) ori r1,r1,0 stw rCHR,36(rMEMP3) ori r1,r1,0 stw rCHR,40(rMEMP3) ori r1,r1,0 stw rCHR,44(rMEMP3) ori r1,r1,0 stw rCHR,48(rMEMP3) ori r1,r1,0 stw rCHR,52(rMEMP3) ori r1,r1,0 stw rCHR,56(rMEMP3) ori r1,r1,0 stw rCHR,60(rMEMP3) blt cr6,L(cacheAligned1) #ifndef NOT_IN_libc lfd 0,-128(rMEMP) #endif b L(nzCacheAligned256) .align 5 L(nzCacheAligned256): cmplwi cr1,rLEN,256 addi rMEMP3,rMEMP,64 #ifdef NOT_IN_libc /* When we are not in libc we should use only GPRs to avoid the FPU lock interrupt. */ stw rCHR,0(rMEMP) stw rCHR,4(rMEMP) stw rCHR,8(rMEMP) stw rCHR,12(rMEMP) stw rCHR,16(rMEMP) stw rCHR,20(rMEMP) stw rCHR,24(rMEMP) stw rCHR,28(rMEMP) stw rCHR,32(rMEMP) stw rCHR,36(rMEMP) stw rCHR,40(rMEMP) stw rCHR,44(rMEMP) stw rCHR,48(rMEMP) stw rCHR,52(rMEMP) stw rCHR,56(rMEMP) stw rCHR,60(rMEMP) addi rMEMP,rMEMP3,64 addi rLEN,rLEN,-128 stw rCHR,0(rMEMP3) stw rCHR,4(rMEMP3) stw rCHR,8(rMEMP3) stw rCHR,12(rMEMP3) stw rCHR,16(rMEMP3) stw rCHR,20(rMEMP3) stw rCHR,24(rMEMP3) stw rCHR,28(rMEMP3) stw rCHR,32(rMEMP3) stw rCHR,36(rMEMP3) stw rCHR,40(rMEMP3) stw rCHR,44(rMEMP3) stw rCHR,48(rMEMP3) stw rCHR,52(rMEMP3) stw rCHR,56(rMEMP3) stw rCHR,60(rMEMP3) #else /* We are in libc and this is a long memset so we can use FPRs and can afford occasional FPU locked interrupts. */ stfd 0,0(rMEMP) stfd 0,8(rMEMP) stfd 0,16(rMEMP) stfd 0,24(rMEMP) stfd 0,32(rMEMP) stfd 0,40(rMEMP) stfd 0,48(rMEMP) stfd 0,56(rMEMP) addi rMEMP,rMEMP3,64 addi rLEN,rLEN,-128 stfd 0,0(rMEMP3) stfd 0,8(rMEMP3) stfd 0,16(rMEMP3) stfd 0,24(rMEMP3) stfd 0,32(rMEMP3) stfd 0,40(rMEMP3) stfd 0,48(rMEMP3) stfd 0,56(rMEMP3) #endif bge cr1,L(nzCacheAligned256) dcbtst 0,rMEMP b L(cacheAligned1) .align 4 /* Storing a zero "c" value. We are aligned at a sector (32-byte) boundary but may not be at cache line (128-byte) boundary. If the remaining length spans a full cache line we can use the Data cache block zero instruction. */ L(zloopstart): /* memset in 32-byte chunks until we get to a cache line boundary. If rLEN is less then the distance to the next cache-line boundary use cacheAligned1 code to finish the tail. */ cmplwi cr1,rLEN,128 beq L(medium) L(getCacheAligned): andi. rTMP,rMEMP,127 blt cr1,L(cacheAligned1) addi rMEMP3,rMEMP,32 beq L(cacheAligned) addi rLEN,rLEN,-32 stw rCHR,0(rMEMP) stw rCHR,4(rMEMP) stw rCHR,8(rMEMP) stw rCHR,12(rMEMP) stw rCHR,16(rMEMP) stw rCHR,20(rMEMP) addi rMEMP,rMEMP,32 andi. rTMP,rMEMP3,127 stw rCHR,-8(rMEMP3) stw rCHR,-4(rMEMP3) L(getCacheAligned2): beq L(cacheAligned) addi rLEN,rLEN,-32 addi rMEMP,rMEMP,32 stw rCHR,0(rMEMP3) stw rCHR,4(rMEMP3) stw rCHR,8(rMEMP3) stw rCHR,12(rMEMP3) andi. rTMP,rMEMP,127 nop stw rCHR,16(rMEMP3) stw rCHR,20(rMEMP3) stw rCHR,24(rMEMP3) stw rCHR,28(rMEMP3) L(getCacheAligned3): beq L(cacheAligned) /* At this point we can overrun the store queue (pipe reject) so it is time to slow things down. The store queue can merge two adjacent stores into a single L1/L2 op, but the L2 is clocked at 1/2 the CPU. So we add "group ending nops" to guarantee that we dispatch only two stores every other cycle. */ addi rLEN,rLEN,-32 ori r1,r1,0 ori r1,r1,0 stw rCHR,32(rMEMP3) stw rCHR,36(rMEMP3) addi rMEMP,rMEMP,32 cmplwi cr1,rLEN,128 ori r1,r1,0 stw rCHR,40(rMEMP3) stw rCHR,44(rMEMP3) cmplwi cr6,rLEN,256 li rMEMP2,128 ori r1,r1,0 stw rCHR,48(rMEMP3) stw rCHR,52(rMEMP3) ori r1,r1,0 ori r1,r1,0 stw rCHR,56(rMEMP3) stw rCHR,60(rMEMP3) blt cr1,L(cacheAligned1) blt cr6,L(cacheAligned128) b L(cacheAlignedx) /* Now we are aligned to the cache line and can use dcbz. */ .align 4 L(cacheAligned): cmplwi cr1,rLEN,128 cmplwi cr6,rLEN,256 blt cr1,L(cacheAligned1) li rMEMP2,128 L(cacheAlignedx): cmplwi cr5,rLEN,640 blt cr6,L(cacheAligned128) bgt cr5,L(cacheAligned512) cmplwi cr6,rLEN,512 dcbz 0,rMEMP cmplwi cr1,rLEN,384 dcbz rMEMP2,rMEMP addi rMEMP,rMEMP,256 addi rLEN,rLEN,-256 blt cr1,L(cacheAligned1) blt cr6,L(cacheAligned128) b L(cacheAligned256) .align 5 /* A simple loop for the longer (>640 bytes) lengths. This form limits the branch miss-predicted to exactly 1 at loop exit.*/ L(cacheAligned512): cmpli cr1,rLEN,128 blt cr1,L(cacheAligned1) dcbz 0,rMEMP addi rLEN,rLEN,-128 addi rMEMP,rMEMP,128 b L(cacheAligned512) .align 5 L(cacheAligned256): cmplwi cr6,rLEN,512 dcbz 0,rMEMP cmplwi cr1,rLEN,384 dcbz rMEMP2,rMEMP addi rMEMP,rMEMP,256 addi rLEN,rLEN,-256 bge cr6,L(cacheAligned256) blt cr1,L(cacheAligned1) .align 4 L(cacheAligned128): dcbz 0,rMEMP addi rMEMP,rMEMP,128 addi rLEN,rLEN,-128 .align 4 L(cacheAligned1): cmplwi cr1,rLEN,32 blt cr1,L(handletail32) addi rMEMP3,rMEMP,32 addi rLEN,rLEN,-32 stw rCHR,0(rMEMP) stw rCHR,4(rMEMP) stw rCHR,8(rMEMP) stw rCHR,12(rMEMP) stw rCHR,16(rMEMP) stw rCHR,20(rMEMP) addi rMEMP,rMEMP,32 cmplwi cr1,rLEN,32 stw rCHR,-8(rMEMP3) stw rCHR,-4(rMEMP3) L(cacheAligned2): blt cr1,L(handletail32) addi rLEN,rLEN,-32 stw rCHR,0(rMEMP3) stw rCHR,4(rMEMP3) stw rCHR,8(rMEMP3) stw rCHR,12(rMEMP3) addi rMEMP,rMEMP,32 cmplwi cr1,rLEN,32 stw rCHR,16(rMEMP3) stw rCHR,20(rMEMP3) stw rCHR,24(rMEMP3) stw rCHR,28(rMEMP3) nop L(cacheAligned3): blt cr1,L(handletail32) /* At this point we can overrun the store queue (pipe reject) so it is time to slow things down. The store queue can merge two adjacent stores into a single L1/L2 op, but the L2 is clocked at 1/2 the CPU. So we add "group ending nops" to guarantee that we dispatch only two stores every other cycle. */ ori r1,r1,0 ori r1,r1,0 addi rMEMP,rMEMP,32 addi rLEN,rLEN,-32 ori r1,r1,0 ori r1,r1,0 stw rCHR,32(rMEMP3) stw rCHR,36(rMEMP3) ori r1,r1,0 ori r1,r1,0 stw rCHR,40(rMEMP3) stw rCHR,44(rMEMP3) ori r1,r1,0 ori r1,r1,0 stw rCHR,48(rMEMP3) stw rCHR,52(rMEMP3) ori r1,r1,0 ori r1,r1,0 stw rCHR,56(rMEMP3) stw rCHR,60(rMEMP3) /* We are here because the length or remainder (rLEN) is less than the cache line/sector size and does not justify aggressive loop unrolling. So set up the preconditions for L(medium) and go there. */ .align 3 L(handletail32): cmplwi cr1,rLEN,0 beqlr cr1 b L(medium) .align 4 L(small): /* Memset of 4 bytes or less. */ cmplwi cr5, rLEN, 1 cmplwi cr1, rLEN, 3 bltlr cr5 stb rCHR, 0(rMEMP) beqlr cr5 stb rCHR, 1(rMEMP) bltlr cr1 stb rCHR, 2(rMEMP) beqlr cr1 stb rCHR, 3(rMEMP) blr /* Memset of 0-31 bytes. */ .align 5 L(medium): cmplwi cr1, rLEN, 16 L(medium_tail2): add rMEMP, rMEMP, rLEN L(medium_tail): bt- 31, L(medium_31t) bt- 30, L(medium_30t) L(medium_30f): bt 29, L(medium_29t) L(medium_29f): bge cr1, L(medium_27t) bflr 28 stw rCHR, -4(rMEMP) stw rCHR, -8(rMEMP) blr L(medium_31t): stbu rCHR, -1(rMEMP) bf- 30, L(medium_30f) L(medium_30t): sthu rCHR, -2(rMEMP) bf- 29, L(medium_29f) L(medium_29t): stwu rCHR, -4(rMEMP) blt cr1, L(medium_27f) L(medium_27t): stw rCHR, -4(rMEMP) stw rCHR, -8(rMEMP) stw rCHR, -12(rMEMP) stwu rCHR, -16(rMEMP) L(medium_27f): bflr 28 L(medium_28t): stw rCHR, -4(rMEMP) stw rCHR, -8(rMEMP) blr END (BP_SYM (memset)) libc_hidden_builtin_def (memset)