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Diffstat (limited to 'sysdeps/powerpc/powerpc64/power4/memcpy.S')
| -rw-r--r-- | sysdeps/powerpc/powerpc64/power4/memcpy.S | 417 |
1 files changed, 417 insertions, 0 deletions
diff --git a/sysdeps/powerpc/powerpc64/power4/memcpy.S b/sysdeps/powerpc/powerpc64/power4/memcpy.S new file mode 100644 index 0000000000..9910ebda82 --- /dev/null +++ b/sysdeps/powerpc/powerpc64/power4/memcpy.S @@ -0,0 +1,417 @@ +/* Optimized memcpy implementation for PowerPC64. + Copyright (C) 2003, 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 <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 a binary move blocks + (no loops) of lwz/stw. The tail (remaining 1-3) bytes is handled + with the appropriate combination of byte and halfword load/stores. + There is minimal effort 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) + CALL_MCOUNT 3 + + cmpldi cr1,5,31 + neg 0,3 + std 3,-16(1) + std 31,-8(1) + cfi_offset(31,-8) + andi. 11,3,7 /* check alignement of dst. */ + clrldi 0,0,61 /* Number of bytes until the 1st doubleword of dst. */ + clrldi 10,4,61 /* check alignement of src. */ + cmpldi cr6,5,8 + ble- cr1,.L2 /* If move < 32 bytes use short move code. */ + cmpld cr6,10,11 + mr 12,4 + srdi 9,5,3 /* Number of full double words remaining. */ + mtcrf 0x01,0 + mr 31,5 + beq .L0 + + subf 31,0,5 + /* Move 0-7 bytes as needed to get the destination doubleword alligned. */ +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: + clrldi 10,12,61 /* check alignement of src again. */ + srdi 9,31,3 /* Number of full double words remaining. */ + + /* Copy doublewords from source to destination, assumpting the + destination is aligned on a doubleword boundary. + + At this point we know there are at least 25 bytes left (32-7) to copy. + The next step is to determine if the source is also doubleword aligned. + If not branch to the unaligned move code at .L6. which uses + a load, shift, store strategy. + + Otherwise source and destination are doubleword aligned, and we can + the optimized doubleword copy loop. */ +.L0: + clrldi 11,31,61 + mtcrf 0x01,9 + cmpldi cr1,11,0 + bne- cr6,.L6 /* If source is not DW aligned. */ + + /* Move doublewords where destination and source are DW aligned. + Use a unrolled loop to copy 4 doubleword (32-bytes) per iteration. + If the the copy is not an exact multiple of 32 bytes, 1-3 + doublewords are copied as needed to set up the main loop. After + the main loop exits there may be a tail of 1-7 bytes. These byte are + copied a word/halfword/byte at a time as needed to preserve alignment. */ + + srdi 8,31,5 + cmpldi cr1,9,4 + cmpldi cr6,11,0 + mr 11,12 + + bf 30,1f + ld 6,0(12) + ld 7,8(12) + addi 11,12,16 + mtctr 8 + std 6,0(3) + std 7,8(3) + addi 10,3,16 + bf 31,4f + ld 0,16(12) + std 0,16(3) + blt cr1,3f + addi 11,12,24 + addi 10,3,24 + b 4f + .align 4 +1: + mr 10,3 + mtctr 8 + bf 31,4f + ld 6,0(12) + addi 11,12,8 + std 6,0(3) + addi 10,3,8 + + .align 4 +4: + ld 6,0(11) + ld 7,8(11) + ld 8,16(11) + ld 0,24(11) + addi 11,11,32 +2: + std 6,0(10) + std 7,8(10) + std 8,16(10) + std 0,24(10) + addi 10,10,32 + bdnz 4b +3: + + rldicr 0,31,0,60 + mtcrf 0x01,31 + beq cr6,0f +.L9: + add 3,3,0 + add 12,12,0 + +/* At this point we have a tail of 0-7 bytes and we know that the + destiniation is double word aligned. */ +4: bf 29,2f + lwz 6,0(12) + addi 12,12,4 + stw 6,0(3) + addi 3,3,4 +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) + stb 6,0(3) +0: + /* Return original dst pointer. */ + ld 31,-8(1) + ld 3,-16(1) + blr + +/* Copy up to 31 bytes. This divided into two cases 0-8 bytes and 9-31 + bytes. Each case is handled without loops, using binary (1,2,4,8) + tests. + + In the short (0-8 byte) case no attempt is made to force alignment + of either source or destination. The hardware will handle the + unaligned load/stores with small delays for crossing 32- 64-byte, and + 4096-byte boundaries. Since these short moves are unlikely to be + unaligned or cross these boundaries, the overhead to force + alignment is not justified. + + The longer (9-31 byte) move is more likely to cross 32- or 64-byte + boundaries. Since only loads are sensitive to the 32-/64-byte + boundaries it is more important to align the source then the + destination. If the source is not already word aligned, we first + move 1-3 bytes as needed. Since we are only word aligned we don't + use double word load/stores to insure that all loads are aligned. + While the destination and stores may still be unaligned, this + is only an issue for page (4096 byte boundary) crossing, which + should be rare for these short moves. The hardware handles this + case automatically with a small delay. */ + + .align 4 +.L2: + mtcrf 0x01,5 + neg 8,4 + clrrdi 11,4,2 + andi. 0,8,3 + ble cr6,.LE8 /* Handle moves of 0-8 bytes. */ +/* At least 9 bytes left. Get the source word aligned. */ + cmpldi cr1,5,16 + mr 10,5 + mr 12,4 + cmpldi cr6,0,2 + beq .L3 /* If the source is already word aligned skip this. */ +/* Copy 1-3 bytes to get source address word aligned. */ + lwz 6,0(11) + subf 10,0,5 + add 12,4,0 + blt cr6,5f + srdi 7,6,16 + bgt cr6,3f + sth 6,0(3) + b 7f + .align 4 +3: + stb 7,0(3) + sth 6,1(3) + b 7f + .align 4 +5: + stb 6,0(3) +7: + cmpldi cr1,10,16 + add 3,3,0 + mtcrf 0x01,10 + .align 4 +.L3: +/* At least 6 bytes left and the source is word aligned. */ + blt cr1,8f +16: /* Move 16 bytes. */ + lwz 6,0(12) + lwz 7,4(12) + stw 6,0(3) + lwz 6,8(12) + stw 7,4(3) + lwz 7,12(12) + addi 12,12,16 + stw 6,8(3) + stw 7,12(3) + addi 3,3,16 +8: /* Move 8 bytes. */ + bf 28,4f + lwz 6,0(12) + lwz 7,4(12) + addi 12,12,8 + stw 6,0(3) + stw 7,4(3) + addi 3,3,8 +4: /* Move 4 bytes. */ + bf 29,2f + lwz 6,0(12) + addi 12,12,4 + stw 6,0(3) + addi 3,3,4 +2: /* Move 2-3 bytes. */ + bf 30,1f + lhz 6,0(12) + sth 6,0(3) + bf 31,0f + lbz 7,2(12) + stb 7,2(3) + ld 3,-16(1) + blr +1: /* Move 1 byte. */ + bf 31,0f + lbz 6,0(12) + stb 6,0(3) +0: + /* Return original dst pointer. */ + ld 3,-16(1) + blr + +/* Special case to copy 0-8 bytes. */ + .align 4 +.LE8: + mr 12,4 + bne cr6,4f +/* Would have liked to use use ld/std here but the 630 processors are + slow for load/store doubles that are not at least word aligned. + Unaligned Load/Store word execute with only a 1 cycle penaltity. */ + lwz 6,0(4) + lwz 7,4(4) + stw 6,0(3) + stw 7,4(3) + /* Return original dst pointer. */ + ld 3,-16(1) + blr + .align 4 +4: bf 29,2b + lwz 6,0(4) + stw 6,0(3) +6: + bf 30,5f + lhz 7,4(4) + sth 7,4(3) + bf 31,0f + lbz 8,6(4) + stb 8,6(3) + ld 3,-16(1) + blr + .align 4 +5: + bf 31,0f + lbz 6,4(4) + stb 6,4(3) + .align 4 +0: + /* Return original dst pointer. */ + ld 3,-16(1) + blr + + .align 4 +.L6: + + /* 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. */ + addi 11,9,-1 /* loop DW count is one less than total */ + subf 5,10,12 + sldi 10,10,3 + mr 4,3 + srdi 8,11,2 /* calculate the 32 byte loop count */ + ld 6,0(5) + mtcrf 0x01,11 + cmpldi cr6,9,4 + mtctr 8 + ld 7,8(5) + subfic 9,10,64 + bf 30,1f + + /* there are at least two DWs to copy */ + sld 0,6,10 + srd 8,7,9 + or 0,0,8 + ld 6,16(5) + std 0,0(4) + sld 0,7,10 + srd 8,6,9 + or 0,0,8 + ld 7,24(5) + std 0,8(4) + addi 4,4,16 + addi 5,5,32 + blt cr6,8f /* if total DWs = 3, then bypass loop */ + bf 31,4f + /* there is a third DW to copy */ + sld 0,6,10 + srd 8,7,9 + or 0,0,8 + std 0,0(4) + mr 6,7 + ld 7,0(5) + addi 5,5,8 + addi 4,4,8 + beq cr6,8f /* if total DWs = 4, then bypass loop */ + b 4f + .align 4 +1: + sld 0,6,10 + srd 8,7,9 + addi 5,5,16 + or 0,0,8 + bf 31,4f + mr 6,7 + ld 7,0(5) + addi 5,5,8 + std 0,0(4) + addi 4,4,8 + .align 4 +/* copy 32 bytes at a time */ +4: sld 0,6,10 + srd 8,7,9 + or 0,0,8 + ld 6,0(5) + std 0,0(4) + sld 0,7,10 + srd 8,6,9 + or 0,0,8 + ld 7,8(5) + std 0,8(4) + sld 0,6,10 + srd 8,7,9 + or 0,0,8 + ld 6,16(5) + std 0,16(4) + sld 0,7,10 + srd 8,6,9 + or 0,0,8 + ld 7,24(5) + std 0,24(4) + addi 5,5,32 + addi 4,4,32 + bdnz+ 4b + .align 4 +8: + /* calculate and store the final DW */ + sld 0,6,10 + srd 8,7,9 + or 0,0,8 + std 0,0(4) +3: + rldicr 0,31,0,60 + mtcrf 0x01,31 + bne cr1,.L9 /* If the tail is 0 bytes we are done! */ + /* Return original dst pointer. */ + ld 31,-8(1) + ld 3,-16(1) + blr +END_GEN_TB (BP_SYM (memcpy),TB_TOCLESS) +libc_hidden_builtin_def (memcpy) |