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Diffstat (limited to 'sysdeps/powerpc/powerpc32/power4/memcpy.S')
| -rw-r--r-- | sysdeps/powerpc/powerpc32/power4/memcpy.S | 425 |
1 files changed, 425 insertions, 0 deletions
diff --git a/sysdeps/powerpc/powerpc32/power4/memcpy.S b/sysdeps/powerpc/powerpc32/power4/memcpy.S new file mode 100644 index 0000000000..c48db2f3df --- /dev/null +++ b/sysdeps/powerpc/powerpc32/power4/memcpy.S @@ -0,0 +1,425 @@ +/* Optimized memcpy implementation for PowerPC32 on 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. + + Longer moves (>= 32-bytes) justify the effort to get at least the + destination word (4-byte) aligned. Further optimization is + possible when both source and destination are word aligned. + Each case has an optimized unrolled loop. */ + +EALIGN (BP_SYM (memcpy), 5, 0) + CALL_MCOUNT + + stwu 1,-32(1) + cfi_adjust_cfa_offset(32) + stw 30,20(1) + cfi_offset(30,(20-32)) + mr 30,3 + cmplwi cr1,5,31 + stw 31,24(1) + cfi_offset(31,(24-32)) + neg 0,3 + andi. 11,3,3 /* check alignment of dst. */ + clrlwi 0,0,30 /* Number of bytes until the 1st word of dst. */ + clrlwi 10,4,30 /* check alignment of src. */ + cmplwi cr6,5,8 + ble- cr1,.L2 /* If move < 32 bytes use short move code. */ + cmplw cr6,10,11 + mr 12,4 + srwi 9,5,2 /* Number of full words remaining. */ + mtcrf 0x01,0 + mr 31,5 + beq .L0 + + subf 31,0,5 + /* Move 0-3 bytes as needed to get the destination word aligned. */ +1: bf 31,2f + lbz 6,0(12) + addi 12,12,1 + stb 6,0(3) + addi 3,3,1 +2: bf 30,0f + lhz 6,0(12) + addi 12,12,2 + sth 6,0(3) + addi 3,3,2 +0: + clrlwi 10,12,30 /* check alignment of src again. */ + srwi 9,31,2 /* Number of full words remaining. */ + + /* Copy words from source to destination, assuming the destination is + aligned on a word 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 word aligned. + If not branch to the unaligned move code at .L6. which uses + a load, shift, store strategy. + + Otherwise source and destination are word aligned, and we can use + the optimized word copy loop. */ +.L0: + clrlwi 11,31,30 /* calculate the number of tail bytes */ + mtcrf 0x01,9 + bne- cr6,.L6 /* If source is not word aligned. */ + + /* Move words where destination and source are word aligned. + Use an unrolled loop to copy 4 words (16-bytes) per iteration. + If the the copy is not an exact multiple of 16 bytes, 1-3 + words are copied as needed to set up the main loop. After + the main loop exits there may be a tail of 1-3 bytes. These bytes are + copied a halfword/byte at a time as needed to preserve alignment. */ + + srwi 8,31,4 /* calculate the 16 byte loop count */ + cmplwi cr1,9,4 + cmplwi cr6,11,0 + mr 11,12 + + bf 30,1f + lwz 6,0(12) + lwz 7,4(12) + addi 11,12,8 + mtctr 8 + stw 6,0(3) + stw 7,4(3) + addi 10,3,8 + bf 31,4f + lwz 0,8(12) + stw 0,8(3) + blt cr1,3f + addi 11,12,12 + addi 10,3,12 + b 4f + .align 4 +1: + mr 10,3 + mtctr 8 + bf 31,4f + lwz 6,0(12) + addi 11,12,4 + stw 6,0(3) + addi 10,3,4 + + .align 4 +4: + lwz 6,0(11) + lwz 7,4(11) + lwz 8,8(11) + lwz 0,12(11) + stw 6,0(10) + stw 7,4(10) + stw 8,8(10) + stw 0,12(10) + addi 11,11,16 + addi 10,10,16 + bdnz 4b +3: + clrrwi 0,31,2 + mtcrf 0x01,31 + beq cr6,0f +.L9: + add 3,3,0 + add 12,12,0 + +/* At this point we have a tail of 0-3 bytes and we know that the + destination is word aligned. */ +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. */ + mr 3,30 + lwz 30,20(1) + lwz 31,24(1) + addi 1,1,32 + blr + +/* Copy up to 31 bytes. This is 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 than the + destination. If the source is not already word aligned, we first + move 1-3 bytes as needed. 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 + clrrwi 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. */ + cmplwi cr1,5,16 + mr 10,5 + mr 12,4 + cmplwi 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 + srwi 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: + cmplwi 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) + mr 3,30 + lwz 30,20(1) + addi 1,1,32 + blr +1: /* Move 1 byte. */ + bf 31,0f + lbz 6,0(12) + stb 6,0(3) +0: + /* Return original dst pointer. */ + mr 3,30 + lwz 30,20(1) + addi 1,1,32 + blr + +/* Special case to copy 0-8 bytes. */ + .align 4 +.LE8: + mr 12,4 + bne cr6,4f + lwz 6,0(4) + lwz 7,4(4) + stw 6,0(3) + stw 7,4(3) + /* Return original dst pointer. */ + mr 3,30 + lwz 30,20(1) + addi 1,1,32 + 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) + mr 3,30 + lwz 30,20(1) + addi 1,1,32 + blr + .align 4 +5: + bf 31,0f + lbz 6,4(4) + stb 6,4(3) + .align 4 +0: + /* Return original dst pointer. */ + mr 3,30 + lwz 30,20(1) + addi 1,1,32 + blr + + .align 4 +.L6: + + /* Copy words where the destination is aligned but the source is + not. Use aligned word loads from the source, shifted to realign + the data, to allow aligned destination stores. + Use an unrolled loop to copy 4 words (16-bytes) per iteration. + A single word is retained for storing at loop exit to avoid walking + off the end of a page within the loop. + If the copy is not an exact multiple of 16 bytes, 1-3 + words are copied as needed to set up the main loop. After + the main loop exits there may be a tail of 1-3 bytes. These bytes are + copied a halfword/byte at a time as needed to preserve alignment. */ + + + cmplwi cr6,11,0 /* are there tail bytes left ? */ + subf 5,10,12 /* back up src pointer to prev word alignment */ + slwi 10,10,3 /* calculate number of bits to shift 1st word left */ + addi 11,9,-1 /* we move one word after the loop */ + srwi 8,11,2 /* calculate the 16 byte loop count */ + lwz 6,0(5) /* load 1st src word into R6 */ + mr 4,3 + lwz 7,4(5) /* load 2nd src word into R7 */ + mtcrf 0x01,11 + subfic 9,10,32 /* number of bits to shift 2nd word right */ + mtctr 8 + bf 30,1f + + /* there are at least two words to copy, so copy them */ + slw 0,6,10 /* shift 1st src word to left align it in R0 */ + srw 8,7,9 /* shift 2nd src word to right align it in R8 */ + or 0,0,8 /* or them to get word to store */ + lwz 6,8(5) /* load the 3rd src word */ + stw 0,0(4) /* store the 1st dst word */ + slw 0,7,10 /* now left align 2nd src word into R0 */ + srw 8,6,9 /* shift 3rd src word to right align it in R8 */ + or 0,0,8 /* or them to get word to store */ + lwz 7,12(5) + stw 0,4(4) /* store the 2nd dst word */ + addi 4,4,8 + addi 5,5,16 + bf 31,4f + /* there is a third word to copy, so copy it */ + slw 0,6,10 /* shift 3rd src word to left align it in R0 */ + srw 8,7,9 /* shift 4th src word to right align it in R8 */ + or 0,0,8 /* or them to get word to store */ + stw 0,0(4) /* store 3rd dst word */ + mr 6,7 + lwz 7,0(5) + addi 5,5,4 + addi 4,4,4 + b 4f + .align 4 +1: + slw 0,6,10 /* shift 1st src word to left align it in R0 */ + srw 8,7,9 /* shift 2nd src word to right align it in R8 */ + addi 5,5,8 + or 0,0,8 /* or them to get word to store */ + bf 31,4f + mr 6,7 + lwz 7,0(5) + addi 5,5,4 + stw 0,0(4) /* store the 1st dst word */ + addi 4,4,4 + + .align 4 +4: + /* copy 16 bytes at a time */ + slw 0,6,10 + srw 8,7,9 + or 0,0,8 + lwz 6,0(5) + stw 0,0(4) + slw 0,7,10 + srw 8,6,9 + or 0,0,8 + lwz 7,4(5) + stw 0,4(4) + slw 0,6,10 + srw 8,7,9 + or 0,0,8 + lwz 6,8(5) + stw 0,8(4) + slw 0,7,10 + srw 8,6,9 + or 0,0,8 + lwz 7,12(5) + stw 0,12(4) + addi 5,5,16 + addi 4,4,16 + bdnz+ 4b +8: + /* calculate and store the final word */ + slw 0,6,10 + srw 8,7,9 + or 0,0,8 + stw 0,0(4) +3: + clrrwi 0,31,2 + mtcrf 0x01,31 + bne cr6,.L9 /* If the tail is 0 bytes we are done! */ + + /* Return original dst pointer. */ + mr 3,30 + lwz 30,20(1) + lwz 31,24(1) + addi 1,1,32 + blr +END (BP_SYM (memcpy)) + +libc_hidden_builtin_def (memcpy) |