/* Optimized memset implementation for PowerPC64. 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 /* __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 (256 bits). There is a special case for setting cache lines to 0, to take advantage of the dcbz instruction. */ .machine power4 EALIGN (memset, 5, 0) CALL_MCOUNT 3 #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 obtained from static. */ #define rCLM r9 /* Cache line size mask to check for cache alignment. */ L(_memset): /* Take care of case for size <= 4. */ cmpldi cr1, rLEN, 8 andi. rALIGN, rMEMP0, 7 mr rMEMP, rMEMP0 ble- cr1, L(small) /* Align to doubleword boundary. */ cmpldi cr5, rLEN, 31 insrdi rCHR, rCHR, 8, 48 /* Replicate byte to halfword. */ beq+ L(aligned2) mtcrf 0x01, rMEMP0 subfic rALIGN, rALIGN, 8 cror 28,30,31 /* Detect odd word aligned. */ add rMEMP, rMEMP, rALIGN sub rLEN, rLEN, rALIGN insrdi rCHR, rCHR, 16, 32 /* Replicate halfword to word. */ bt 29, L(g4) /* Process the even word of doubleword. */ bf+ 31, L(g2) stb rCHR, 0(rMEMP0) bt 30, L(g4x) L(g2): sth rCHR, -6(rMEMP) L(g4x): stw rCHR, -4(rMEMP) b L(aligned) /* Process the odd word of doubleword. */ L(g4): bf 28, L(g4x) /* If false, word aligned on odd word. */ 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(aligned2): insrdi rCHR, rCHR, 16, 32 /* Replicate halfword to word. */ L(aligned): mtcrf 0x01, rLEN ble cr5, L(medium) /* Align to 32-byte boundary. */ andi. rALIGN, rMEMP, 0x18 subfic rALIGN, rALIGN, 0x20 insrdi rCHR, rCHR, 32, 0 /* Replicate word to double word. */ 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) stdu rCHR, -8(rMEMP2) L(a1): blt cr1, L(a2) std rCHR, -8(rMEMP2) stdu rCHR, -16(rMEMP2) L(a2): /* Now aligned to a 32 byte boundary. */ L(caligned): cmpldi cr1, rCHR, 0 clrrdi. rALIGN, rLEN, 5 mtcrf 0x01, rLEN beq cr1, L(zloopstart) /* Special case for clearing memory using dcbz. */ L(nondcbz): srdi rTMP, rALIGN, 5 mtctr rTMP beq L(medium) /* We may not actually get to do a full line. */ clrldi. rLEN, rLEN, 59 add rMEMP, rMEMP, rALIGN li rNEG64, -0x40 bdz L(cloopdone) L(c3): dcbtst rNEG64, rMEMP std rCHR, -8(rMEMP) std rCHR, -16(rMEMP) std rCHR, -24(rMEMP) stdu rCHR, -32(rMEMP) bdnz L(c3) L(cloopdone): std rCHR, -8(rMEMP) std rCHR, -16(rMEMP) cmpldi cr1, rLEN, 16 std rCHR, -24(rMEMP) stdu 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 */ /* Now we know the cache line size, and it is not 32-bytes, but we may not yet be aligned to the cache line. May have a partial line to fill, so touch it 1st. */ dcbt 0,rMEMP L(getCacheAligned): cmpldi cr1,rLEN,32 andi. rTMP,rMEMP,127 blt cr1,L(handletail32) beq L(cacheAligned) addi rMEMP,rMEMP,32 addi rLEN,rLEN,-32 std rCHR,-32(rMEMP) std rCHR,-24(rMEMP) std rCHR,-16(rMEMP) std rCHR,-8(rMEMP) b L(getCacheAligned) /* Now we are aligned to the cache line and can use dcbz. */ L(cacheAligned): cmpld 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 was not 32-bytes 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 8 bytes or less. */ cmpldi cr6, rLEN, 4 cmpldi cr5, rLEN, 1 ble cr6,L(le4) subi rLEN, rLEN, 4 stb rCHR,0(rMEMP) stb rCHR,1(rMEMP) stb rCHR,2(rMEMP) stb rCHR,3(rMEMP) addi rMEMP,rMEMP, 4 cmpldi cr5, rLEN, 1 L(le4): cmpldi 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): insrdi rCHR, rCHR, 32, 0 /* Replicate word to double word. */ cmpldi 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 std 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): std rCHR, -8(rMEMP) stdu rCHR, -16(rMEMP) L(medium_27f): bflr- 28 L(medium_28t): std rCHR, -8(rMEMP) blr END_GEN_TB (memset,TB_TOCLESS) libc_hidden_builtin_def (memset) /* Copied from bzero.S to prevent the linker from inserting a stub between bzero and memset. */ ENTRY (__bzero) CALL_MCOUNT 3 mr r5,r4 li r4,0 b L(_memset) END_GEN_TB (__bzero,TB_TOCLESS) weak_alias (__bzero, bzero)