diff options
Diffstat (limited to 'sysdeps')
| -rw-r--r-- | sysdeps/powerpc/powerpc64/memcpy.S | 210 |
1 files changed, 210 insertions, 0 deletions
diff --git a/sysdeps/powerpc/powerpc64/memcpy.S b/sysdeps/powerpc/powerpc64/memcpy.S new file mode 100644 index 0000000..4da5c2a --- /dev/null +++ b/sysdeps/powerpc/powerpc64/memcpy.S @@ -0,0 +1,210 @@ +/* Optimized memcpy implementation for PowerPC64. + Copyright (C) 2003 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., 59 Temple Place, Suite 330, Boston, MA + 02111-1307 USA. */ + +#include <sysdep.h> +#include <bp-sym.h> +#include <bp-asm.h> + +/* __ptr_t [r3] memcpy (__ptr_t dst [r3], __ptr_t src [r4], size_t len [r5]); + Returns 'dst'. + + Memcpy handles short copies (< 32-bytes) using an unaligned + word lwz/stw loop. The tail (remaining 1-3) bytes is handled with the + appropriate combination of byte and halfword load/stores. There is no + attempt to optimize the alignment of short moves. The 64-bit + implementations of POWER3 and POWER4 do a reasonable job of handling + unligned load/stores that do not cross 32-byte boundries. + + Longer moves (>= 32-bytes) justify the effort to get at least the + destination doubleword (8-byte) aligned. Further optimization is + posible when both source and destination are doubleword aligned. + Each case has a optimized unrolled loop. */ + +EALIGN (BP_SYM (memcpy), 5, 0) + cmpldi cr1,5,31 + neg 0,3 + std 30,-16(1) + std 31,-8(1) + rldicl. 0,0,0,61 + mr 12,4 + mr 31,5 + mr 30,3 + ble- cr1,.L2 + subf 31,0,5 + + /* Move 0-7 bytes as needed to get the destination doubleword alligned. */ + beq 0f + mtcrf 0x01,0 +1: bf 31,2f + lbz 6,0(12) + addi 12,12,1 + stb 6,0(3) + addi 3,3,1 +2: bf 30,4f + lhz 6,0(12) + addi 12,12,2 + sth 6,0(3) + addi 3,3,2 +4: bf 29,0f + lwz 6,0(12) + addi 12,12,4 + stw 6,0(3) + addi 3,3,4 +0: + /* Copy doublewords from source to destination, assumpting the + destination is aligned on a doubleword boundary. + + First verify that there is > 7 bytes to copy and check if the source + is also doubleword aligned. If there are < 8 bytes to copy fall + through to the tail byte copy code. Otherwise if the source and + destination are both doubleword aligned use an optimized doubleword + copy loop. Otherwise the source has a different alignment and we use + a load, shift, store strategy. */ + rldicl. 0,12,0,61 + cmpldi cr6,31,7 + ble- cr6,.L2 /* less than 8 bytes left. */ + bne- 0,.L6 /* Source is not DW aligned. */ + srdi. 9,31,3 + mr 10,3 + mr 11,12 + + /* Move doublewords where destination and source are aligned. + Use a unrolled loop to copy 4 doubleword (32-bytes) per iteration. + If the remainder is >0 and < 32 bytes copy 1-3 doublewords. */ + cmpldi cr1,9,4 + beq 0f + mtcrf 0x01,9 + blt cr1,2f + ld 6,0(11) + .align 4 +4: + ld 7,8(11) + addi 9,9,-4 + std 6,0(10) + ld 6,16(11) + std 7,8(10) + ld 7,24(11) + addi 11,11,32 + cmpldi cr1,9,4 + std 6,16(10) + blt cr1,3f + ld 6,0(11) + std 7,24(10) + addi 10,10,32 + b 4b +3: std 7,24(10) + addi 10,10,32 +2: bf 30,1f + ld 6,0(11) + ld 7,8(11) + addi 11,11,16 + std 6,0(10) + std 7,8(10) + addi 10,10,16 +1: bf 31,0f + ld 6,0(11) + addi 11,11,8 + std 6,0(10) + addi 10,10,8 +0: + +.L8: + rldicr 0,31,0,60 + rldicl 31,31,0,61 + add 3,3,0 + add 12,12,0 + + /* Copy the tail for up to 31 bytes. If this is the tail of a longer + copy then the destination will be aligned and the length will be + less than 8. So it is normally not worth the set-up overhead to + get doubleword aligned and do doubleword load/store. */ +.L2: + mr. 10,31 + cmpldi cr1,31,4 + beq 0f + mtcrf 0x01,31 + blt cr1,2f +4: lwz 6,0(12) + addi 12,12,4 + addi 10,10,-4 + stw 6,0(3) + cmpldi cr1,10,4 + addi 3,3,4 + bge cr1,4b +2: bf 30,1f + lhz 6,0(12) + addi 12,12,2 + sth 6,0(3) + addi 3,3,2 +1: bf 31,0f + lbz 6,0(12) + addi 12,12,1 + stb 6,0(3) + addi 3,3,1 +0: + /* Return original dst pointer. */ + ld 31,-8(1) + mr 3,30 + ld 30,-16(1) + blr + +.L6: + srdi 11,31,3 + mr 4,3 + mr 5,12 + + /* Copy doublewords where the destination is aligned but the source is + not. Use aligned doubleword loads from the source, shifted to realign + the data, to allow aligned destination stores. */ + andi. 10,5,7 + andi. 0,11,1 + subf 5,10,5 + ld 6,0(5) + sldi 10,10,3 + ld 7,8(5) + subfic 9,10,64 + beq 2f + sld 0,6,10 + addi 11,11,-1 + mr 6,7 + addi 4,4,-8 + cmpldi 11,0 + b 1f +2: addi 5,5,8 + .align 4 +0: sld 0,6,10 + srd 8,7,9 + addi 11,11,-2 + ld 6,8(5) + or 0,0,8 + cmpldi 11,0 + std 0,0(4) + sld 0,7,10 +1: srd 8,6,9 + or 0,0,8 + beq 8f + ld 7,16(5) + std 0,8(4) + addi 5,5,16 + addi 4,4,16 + b 0b +8: + std 0,8(4) + b .L8 +END_GEN_TB (BP_SYM (memcpy),TB_TOCLESS) |