| /* Optimized memset implementation for PowerPC64. |
| Copyright (C) 1997-2018 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/>. */ |
| |
| #include <sysdep.h> |
| |
| /* void * [r3] memset (void *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 (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 |
| insrwi rCHR, rCHR, 8, 16 /* 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 |
| insrwi rCHR, rCHR, 16, 0 /* 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 (memset) |
| libc_hidden_builtin_def (memset) |
