/* Optimized memcpy implementation for PowerPC32 on POWER6. Copyright (C) 2003-2013 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] 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. */ .machine power6 EALIGN (memcpy, 5, 0) CALL_MCOUNT stwu 1,-32(1) cfi_adjust_cfa_offset(32) cmplwi cr1,5,31 /* check for short move. */ neg 0,3 cmplwi cr1,5,31 clrlwi 10,4,30 /* check alignment of src. */ andi. 11,3,3 /* check alignment of dst. */ clrlwi 0,0,30 /* Number of bytes until the 1st word of dst. */ ble- cr1,L(word_unaligned_short) /* If move < 32 bytes. */ cmplw cr6,10,11 stw 31,24(1) cfi_offset(31,(24-32)) stw 30,20(1) cfi_offset(30,(20-32)) mr 30,3 beq .L0 mtcrf 0x01,0 subf 31,0,5 /* Length after alignment. */ add 12,4,0 /* Compute src addr after alignment. */ /* Move 0-3 bytes as needed to get the destination word aligned. */ 1: bf 31,2f lbz 6,0(4) bf 30,3f lhz 7,1(4) stb 6,0(3) sth 7,1(3) addi 3,3,3 b 0f 3: stb 6,0(3) addi 3,3,1 b 0f 2: bf 30,0f lhz 6,0(4) 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. */ bne- cr6,L(wdu) /* If source is not word aligned. .L6 */ clrlwi 11,31,30 /* calculate the number of tail bytes */ b L(word_aligned) /* Copy words from source to destination, assuming the destination is aligned on a word boundary. At this point we know there are at least 29 bytes left (32-3) 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. */ .align 4 .L0: mr 31,5 mr 12,4 bne- cr6,L(wdu) /* If source is not word aligned. .L6 */ srwi 9,5,2 /* Number of full words remaining. */ clrlwi 11,5,30 /* calculate the number of tail bytes */ /* Move words where destination and source are word aligned. Use an unrolled loop to copy 4 words (16-bytes) per iteration. 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. */ L(word_aligned): mtcrf 0x01,9 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 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- 128-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 128-byte boundaries. Since only loads are sensitive to the 32-/128-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 (~20 cycle) delay. */ .align 4 cfi_same_value (31) cfi_same_value (30) L(word_unaligned_short): mtcrf 0x01,5 cmplwi cr6,5,8 neg 8,4 clrrwi 9,4,2 andi. 0,8,3 beq cr6,L(wus_8) /* Handle moves of 8 bytes. */ /* At least 9 bytes left. Get the source word aligned. */ cmplwi cr1,5,16 mr 12,4 ble cr6,L(wus_4) /* Handle moves of 0-8 bytes. */ mr 11,3 mr 10,5 cmplwi cr6,0,2 beq L(wus_tail) /* If the source is already word aligned skip this. */ /* Copy 1-3 bytes to get source address word aligned. */ lwz 6,0(9) 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 11,3,0 mtcrf 0x01,10 .align 4 L(wus_tail): /* At least 6 bytes left and the source is word aligned. This allows some speculative loads up front. */ /* We need to special case the fall-through because the biggest delays are due to address computation not being ready in time for the AGEN. */ lwz 6,0(12) lwz 7,4(12) blt cr1,L(wus_tail8) cmplwi cr0,10,24 L(wus_tail16): /* Move 16 bytes. */ stw 6,0(11) stw 7,4(11) lwz 6,8(12) lwz 7,12(12) stw 6,8(11) stw 7,12(11) /* Move 8 bytes more. */ bf 28,L(wus_tail16p8) cmplwi cr1,10,28 lwz 6,16(12) lwz 7,20(12) stw 6,16(11) stw 7,20(11) /* Move 4 bytes more. */ bf 29,L(wus_tail16p4) lwz 6,24(12) stw 6,24(11) addi 12,12,28 addi 11,11,28 bgt cr1,L(wus_tail2) /* exactly 28 bytes. Return original dst pointer and exit. */ addi 1,1,32 blr .align 4 L(wus_tail16p8): /* less than 8 bytes left. */ beq cr1,L(wus_tailX) /* exactly 16 bytes, early exit. */ cmplwi cr1,10,20 bf 29,L(wus_tail16p2) /* Move 4 bytes more. */ lwz 6,16(12) stw 6,16(11) addi 12,12,20 addi 11,11,20 bgt cr1,L(wus_tail2) /* exactly 20 bytes. Return original dst pointer and exit. */ addi 1,1,32 blr .align 4 L(wus_tail16p4): /* less than 4 bytes left. */ addi 12,12,24 addi 11,11,24 bgt cr0,L(wus_tail2) /* exactly 24 bytes. Return original dst pointer and exit. */ addi 1,1,32 blr .align 4 L(wus_tail16p2): /* 16 bytes moved, less than 4 bytes left. */ addi 12,12,16 addi 11,11,16 b L(wus_tail2) .align 4 L(wus_tail8): /* Move 8 bytes. */ /* r6, r7 already loaded speculatively. */ cmplwi cr1,10,8 cmplwi cr0,10,12 bf 28,L(wus_tail4) stw 6,0(11) stw 7,4(11) /* Move 4 bytes more. */ bf 29,L(wus_tail8p4) lwz 6,8(12) stw 6,8(11) addi 12,12,12 addi 11,11,12 bgt cr0,L(wus_tail2) /* exactly 12 bytes. Return original dst pointer and exit. */ addi 1,1,32 blr .align 4 L(wus_tail8p4): /* less than 4 bytes left. */ addi 12,12,8 addi 11,11,8 bgt cr1,L(wus_tail2) /* exactly 8 bytes. Return original dst pointer and exit. */ addi 1,1,32 blr .align 4 L(wus_tail4): /* Move 4 bytes. */ /* r6 already loaded speculatively. If we are here we know there is more than 4 bytes left. So there is no need to test. */ addi 12,12,4 stw 6,0(11) addi 11,11,4 L(wus_tail2): /* Move 2-3 bytes. */ bf 30,L(wus_tail1) lhz 6,0(12) sth 6,0(11) bf 31,L(wus_tailX) lbz 7,2(12) stb 7,2(11) addi 1,1,32 blr L(wus_tail1): /* Move 1 byte. */ bf 31,L(wus_tailX) lbz 6,0(12) stb 6,0(11) L(wus_tailX): /* Return original dst pointer. */ addi 1,1,32 blr /* Special case to copy 0-8 bytes. */ .align 4 L(wus_8): lwz 6,0(4) lwz 7,4(4) stw 6,0(3) stw 7,4(3) /* Return original dst pointer. */ addi 1,1,32 blr .align 4 L(wus_4): bf 29,L(wus_2) lwz 6,0(4) stw 6,0(3) bf 30,L(wus_5) lhz 7,4(4) sth 7,4(3) bf 31,L(wus_0) lbz 8,6(4) stb 8,6(3) addi 1,1,32 blr .align 4 L(wus_5): bf 31,L(wus_0) lbz 6,4(4) stb 6,4(3) /* Return original dst pointer. */ addi 1,1,32 blr .align 4 L(wus_2): /* Move 2-3 bytes. */ bf 30,L(wus_1) lhz 6,0(4) sth 6,0(3) bf 31,L(wus_0) lbz 7,2(4) stb 7,2(3) addi 1,1,32 blr .align 4 L(wus_1): /* Move 1 byte. */ bf 31,L(wus_0) lbz 6,0(4) stb 6,0(3) .align 3 L(wus_0): /* Return original dst pointer. */ addi 1,1,32 blr .align 4 cfi_offset(31,(24-32)) cfi_offset(30,(20-32)) L(wdu): /* Copy words where the destination is aligned but the source is not. For power4, power5 and power6 machines there is penalty for unaligned loads (src) that cross 32-byte, cacheline, or page boundaries. So we want to use simple (unaligned) loads where possible but avoid them where we know the load would span a 32-byte boundary. At this point we know we have at least 29 (32-3) bytes to copy the src is unaligned. and we may cross at least one 32-byte boundary. Also we have the following register values: r3 == adjusted dst, word aligned r4 == unadjusted src r5 == unadjusted len r9 == adjusted Word length r10 == src alignment (1-3) r12 == adjusted src, not aligned r31 == adjusted len First we need to copy word up to but not crossing the next 32-byte boundary. Then perform aligned loads just before and just after the boundary and use shifts and or to generate the next aligned word for dst. If more than 32 bytes remain we copy (unaligned src) the next 7 words and repeat the loop until less than 32-bytes remain. Then if more than 4 bytes remain we again use aligned loads, shifts and or to generate the next dst word. We then process the remaining words using unaligned loads as needed. Finally we check if there are more than 0 bytes (1-3) bytes remaining and use halfword and or byte load/stores to complete the copy. */ mr 4,12 /* restore unaligned adjusted src ptr */ clrlwi 0,12,27 /* Find dist from previous 32-byte boundary. */ slwi 10,10,3 /* calculate number of bits to shift 1st word left */ cmplwi cr5,0,16 subfic 8,0,32 /* Number of bytes to next 32-byte boundary. */ mtcrf 0x01,8 cmplwi cr1,10,16 subfic 9,10,32 /* number of bits to shift 2nd word right */ /* This test is reversed because the timing to compare the bytes to 32-byte boundary could not be meet. So we compare the bytes from previous 32-byte boundary and invert the test. */ bge cr5,L(wdu_h32_8) .align 4 lwz 6,0(4) lwz 7,4(4) addi 12,4,16 /* generate alternate pointers to avoid agen */ addi 11,3,16 /* timing issues downstream. */ stw 6,0(3) stw 7,4(3) subi 31,31,16 lwz 6,8(4) lwz 7,12(4) addi 4,4,16 stw 6,8(3) stw 7,12(3) addi 3,3,16 bf 28,L(wdu_h32_4) lwz 6,0(12) lwz 7,4(12) subi 31,31,8 addi 4,4,8 stw 6,0(11) stw 7,4(11) addi 3,3,8 bf 29,L(wdu_h32_0) lwz 6,8(12) addi 4,4,4 subi 31,31,4 stw 6,8(11) addi 3,3,4 b L(wdu_h32_0) .align 4 L(wdu_h32_8): bf 28,L(wdu_h32_4) lwz 6,0(4) lwz 7,4(4) subi 31,31,8 bf 29,L(wdu_h32_8x) stw 6,0(3) stw 7,4(3) lwz 6,8(4) addi 4,4,12 subi 31,31,4 stw 6,8(3) addi 3,3,12 b L(wdu_h32_0) .align 4 L(wdu_h32_8x): addi 4,4,8 stw 6,0(3) stw 7,4(3) addi 3,3,8 b L(wdu_h32_0) .align 4 L(wdu_h32_4): bf 29,L(wdu_h32_0) lwz 6,0(4) subi 31,31,4 addi 4,4,4 stw 6,0(3) addi 3,3,4 .align 4 L(wdu_h32_0): /* set up for 32-byte boundary crossing word move and possibly 32-byte move loop. */ clrrwi 12,4,2 cmplwi cr5,31,32 bge cr1,L(wdu2_32) #if 0 b L(wdu1_32) /* cmplwi cr1,10,8 beq cr1,L(wdu1_32) cmplwi cr1,10,16 beq cr1,L(wdu2_32) cmplwi cr1,10,24 beq cr1,L(wdu3_32) */ L(wdu_32): lwz 6,0(12) cmplwi cr6,31,4 srwi 8,31,5 /* calculate the 32 byte loop count */ slw 0,6,10 clrlwi 31,31,27 /* The remaining bytes, < 32. */ blt cr5,L(wdu_32tail) mtctr 8 cmplwi cr6,31,4 .align 4 L(wdu_loop32): /* copy 32 bytes at a time */ lwz 8,4(12) addi 12,12,32 lwz 7,4(4) srw 8,8,9 or 0,0,8 stw 0,0(3) stw 7,4(3) lwz 6,8(4) lwz 7,12(4) stw 6,8(3) stw 7,12(3) lwz 6,16(4) lwz 7,20(4) stw 6,16(3) stw 7,20(3) lwz 6,24(4) lwz 7,28(4) lwz 8,0(12) addi 4,4,32 stw 6,24(3) stw 7,28(3) addi 3,3,32 slw 0,8,10 bdnz+ L(wdu_loop32) L(wdu_32tail): mtcrf 0x01,31 cmplwi cr5,31,16 blt cr6,L(wdu_4tail) /* calculate and store the final word */ lwz 8,4(12) srw 8,8,9 or 6,0,8 b L(wdu_32tailx) #endif .align 4 L(wdu1_32): lwz 6,-1(4) cmplwi cr6,31,4 srwi 8,31,5 /* calculate the 32 byte loop count */ slwi 6,6,8 clrlwi 31,31,27 /* The remaining bytes, < 32. */ blt cr5,L(wdu1_32tail) mtctr 8 cmplwi cr6,31,4 lwz 8,3(4) lwz 7,4(4) /* Equivalent to: srwi 8,8,32-8; or 6,6,8 */ rlwimi 6,8,8,(32-8),31 b L(wdu1_loop32x) .align 4 L(wdu1_loop32): /* copy 32 bytes at a time */ lwz 8,3(4) lwz 7,4(4) stw 10,-8(3) stw 11,-4(3) /* Equivalent to srwi 8,8,32-8; or 6,6,8 */ rlwimi 6,8,8,(32-8),31 L(wdu1_loop32x): lwz 10,8(4) lwz 11,12(4) stw 6,0(3) stw 7,4(3) lwz 6,16(4) lwz 7,20(4) stw 10,8(3) stw 11,12(3) lwz 10,24(4) lwz 11,28(4) lwz 8,32-1(4) addi 4,4,32 stw 6,16(3) stw 7,20(3) addi 3,3,32 slwi 6,8,8 bdnz+ L(wdu1_loop32) stw 10,-8(3) stw 11,-4(3) L(wdu1_32tail): mtcrf 0x01,31 cmplwi cr5,31,16 blt cr6,L(wdu_4tail) /* calculate and store the final word */ lwz 8,3(4) /* Equivalent to: srwi 8,8,32-9; or 6,6,8 */ rlwimi 6,8,8,(32-8),31 b L(wdu_32tailx) L(wdu2_32): bgt cr1,L(wdu3_32) lwz 6,-2(4) cmplwi cr6,31,4 srwi 8,31,5 /* calculate the 32 byte loop count */ slwi 6,6,16 clrlwi 31,31,27 /* The remaining bytes, < 32. */ blt cr5,L(wdu2_32tail) mtctr 8 cmplwi cr6,31,4 lwz 8,2(4) lwz 7,4(4) /* Equivalent to: srwi 8,8,32-8; or 6,6,8 */ rlwimi 6,8,16,(32-16),31 b L(wdu2_loop32x) .align 4 L(wdu2_loop32): /* copy 32 bytes at a time */ lwz 8,2(4) lwz 7,4(4) stw 10,-8(3) stw 11,-4(3) /* Equivalent to srwi 8,8,32-8; or 6,6,8 */ rlwimi 6,8,16,(32-16),31 L(wdu2_loop32x): lwz 10,8(4) lwz 11,12(4) stw 6,0(3) stw 7,4(3) lwz 6,16(4) lwz 7,20(4) stw 10,8(3) stw 11,12(3) lwz 10,24(4) lwz 11,28(4) /* lwz 8,0(12) */ lwz 8,32-2(4) addi 4,4,32 stw 6,16(3) stw 7,20(3) addi 3,3,32 slwi 6,8,16 bdnz+ L(wdu2_loop32) stw 10,-8(3) stw 11,-4(3) L(wdu2_32tail): mtcrf 0x01,31 cmplwi cr5,31,16 blt cr6,L(wdu_4tail) /* calculate and store the final word */ lwz 8,2(4) /* Equivalent to: srwi 8,8,32-9; or 6,6,8 */ rlwimi 6,8,16,(32-16),31 b L(wdu_32tailx) L(wdu3_32): /* lwz 6,0(12) */ lwz 6,-3(4) cmplwi cr6,31,4 srwi 8,31,5 /* calculate the 32 byte loop count */ slwi 6,6,24 clrlwi 31,31,27 /* The remaining bytes, < 32. */ blt cr5,L(wdu3_32tail) mtctr 8 cmplwi cr6,31,4 lwz 8,1(4) lwz 7,4(4) /* Equivalent to: srwi 8,8,32-8; or 6,6,8 */ rlwimi 6,8,24,(32-24),31 b L(wdu3_loop32x) .align 4 L(wdu3_loop32): /* copy 32 bytes at a time */ lwz 8,1(4) lwz 7,4(4) stw 10,-8(3) stw 11,-4(3) /* Equivalent to srwi 8,8,32-8; or 6,6,8 */ rlwimi 6,8,24,(32-24),31 L(wdu3_loop32x): lwz 10,8(4) lwz 11,12(4) stw 6,0(3) stw 7,4(3) lwz 6,16(4) lwz 7,20(4) stw 10,8(3) stw 11,12(3) lwz 10,24(4) lwz 11,28(4) lwz 8,32-3(4) addi 4,4,32 stw 6,16(3) stw 7,20(3) addi 3,3,32 slwi 6,8,24 bdnz+ L(wdu3_loop32) stw 10,-8(3) stw 11,-4(3) L(wdu3_32tail): mtcrf 0x01,31 cmplwi cr5,31,16 blt cr6,L(wdu_4tail) /* calculate and store the final word */ lwz 8,1(4) /* Equivalent to: srwi 8,8,32-9; or 6,6,8 */ rlwimi 6,8,24,(32-24),31 b L(wdu_32tailx) .align 4 L(wdu_32tailx): blt cr5,L(wdu_t32_8) lwz 7,4(4) addi 12,4,16 /* generate alternate pointers to avoid agen */ addi 11,3,16 /* timing issues downstream. */ stw 6,0(3) stw 7,4(3) subi 31,31,16 lwz 6,8(4) lwz 7,12(4) addi 4,4,16 stw 6,8(3) stw 7,12(3) addi 3,3,16 bf 28,L(wdu_t32_4x) lwz 6,0(12) lwz 7,4(12) addi 4,4,8 subi 31,31,8 stw 6,0(11) stw 7,4(11) addi 3,3,8 bf 29,L(wdu_t32_0) lwz 6,8(12) addi 4,4,4 subi 31,31,4 stw 6,8(11) addi 3,3,4 b L(wdu_t32_0) .align 4 L(wdu_t32_4x): bf 29,L(wdu_t32_0) lwz 6,0(4) addi 4,4,4 subi 31,31,4 stw 6,0(3) addi 3,3,4 b L(wdu_t32_0) .align 4 L(wdu_t32_8): bf 28,L(wdu_t32_4) lwz 7,4(4) subi 31,31,8 bf 29,L(wdu_t32_8x) stw 6,0(3) stw 7,4(3) lwz 6,8(4) subi 31,31,4 addi 4,4,12 stw 6,8(3) addi 3,3,12 b L(wdu_t32_0) .align 4 L(wdu_t32_8x): addi 4,4,8 stw 6,0(3) stw 7,4(3) addi 3,3,8 b L(wdu_t32_0) .align 4 L(wdu_t32_4): subi 31,31,4 stw 6,0(3) addi 4,4,4 addi 3,3,4 .align 4 L(wdu_t32_0): L(wdu_4tail): cmplwi cr6,31,0 beq cr6,L(wdus_0) /* If the tail is 0 bytes we are done! */ bf 30,L(wdus_3) lhz 7,0(4) sth 7,0(3) bf 31,L(wdus_0) lbz 8,2(4) stb 8,2(3) mr 3,30 lwz 30,20(1) lwz 31,24(1) addi 1,1,32 blr .align 4 L(wdus_3): bf 31,L(wus_0) lbz 6,0(4) stb 6,0(3) .align 4 L(wdus_0): /* Return original dst pointer. */ mr 3,30 lwz 30,20(1) lwz 31,24(1) addi 1,1,32 blr END (memcpy) libc_hidden_builtin_def (memcpy)