/* Optimized memset implementation for PowerPC64. Copyright (C) 1997,99, 2000,02,03, 2006 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, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301 USA. */ #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 power4 EALIGN (BP_SYM (memset), 5, 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 rCLS r8 /* Cache line size (known to be 128). */ #define rCLM r9 /* Cache line size mask to check for cache alignment. */ 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) /* 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) 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) /* 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): srwi rTMP, rALIGN, 5 mtctr rTMP beq L(medium) /* We may not actually get to do a full line. */ clrlwi. rLEN, rLEN, 27 add rMEMP, rMEMP, rALIGN li rNEG64, -0x40 bdz L(cloopdone) .align 4 L(c3): dcbtst rNEG64, 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) stwu rCHR, -32(rMEMP) bdnz L(c3) L(cloopdone): stw rCHR, -4(rMEMP) stw rCHR, -8(rMEMP) stw rCHR, -12(rMEMP) stw rCHR, -16(rMEMP) cmplwi cr1, rLEN, 16 stw rCHR, -20(rMEMP) stw rCHR, -24(rMEMP) stw rCHR, -28(rMEMP) stwu rCHR, -32(rMEMP) beqlr add rMEMP, rMEMP, rALIGN b L(medium_tail2) .align 5 /* Clear lines of memory in 128-byte chunks. */ L(zloopstart): /* If the remaining length is less the 32 bytes, don't bother getting the cache line size. */ beq L(medium) li rCLS,128 /* cache line size is 128 */ dcbt 0,rMEMP L(getCacheAligned): cmplwi cr1,rLEN,32 andi. rTMP,rMEMP,127 blt cr1,L(handletail32) beq L(cacheAligned) addi rMEMP,rMEMP,32 addi rLEN,rLEN,-32 stw rCHR,-32(rMEMP) stw rCHR,-28(rMEMP) stw rCHR,-24(rMEMP) stw rCHR,-20(rMEMP) stw rCHR,-16(rMEMP) stw rCHR,-12(rMEMP) stw rCHR,-8(rMEMP) stw rCHR,-4(rMEMP) b L(getCacheAligned) /* Now we are aligned to the cache line and can use dcbz. */ .align 4 L(cacheAligned): cmplw cr1,rLEN,rCLS blt cr1,L(handletail32) dcbz 0,rMEMP subf rLEN,rCLS,rLEN add rMEMP,rMEMP,rCLS b L(cacheAligned) /* We are here because the cache line size was set and the remainder (rLEN) is less than the actual cache line size. So set up the preconditions for L(nondcbz) and go there. */ L(handletail32): clrrwi. rALIGN, rLEN, 5 b L(nondcbz) .align 5 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)