From 94e358f6d490650c714edb1ffc3a52f56ffe086e Mon Sep 17 00:00:00 2001 From: Anton Youdkevitch Date: Fri, 5 Apr 2019 13:59:54 -0700 Subject: aarch64: thunderx2 memcpy implementation cleanup and streamlining Here is the updated patch for improving the long unaligned code path (the one using "ext" instruction). 1. Always taken conditional branch at the beginning is removed. 2. Epilogue code is placed after the end of the loop to reduce the number of branches. 3. The redundant "mov" instructions inside the loop are gone due to the changed order of the registers in the "ext" instructions inside the loop, the prologue has additional "ext" instruction. 4.Updating count in the prologue was hoisted out as it is the same update for each prologue. 5. Invariant code of the loop epilogue was hoisted out. 6. As the current size of the ext chunk is exactly 16 instructions long "nop" was added at the beginning of the code sequence so that the loop entry for all the chunks be aligned. * sysdeps/aarch64/multiarch/memcpy_thunderx2.S: Cleanup branching and remove redundant code. --- sysdeps/aarch64/multiarch/memcpy_thunderx2.S | 43 ++++++++++++++-------------- 1 file changed, 22 insertions(+), 21 deletions(-) (limited to 'sysdeps') diff --git a/sysdeps/aarch64/multiarch/memcpy_thunderx2.S b/sysdeps/aarch64/multiarch/memcpy_thunderx2.S index b2215c1809..45e9a29495 100644 --- a/sysdeps/aarch64/multiarch/memcpy_thunderx2.S +++ b/sysdeps/aarch64/multiarch/memcpy_thunderx2.S @@ -382,7 +382,8 @@ L(bytes_0_to_3): strb A_lw, [dstin] strb B_lw, [dstin, tmp1] strb A_hw, [dstend, -1] -L(end): ret +L(end): + ret .p2align 4 @@ -544,43 +545,35 @@ L(dst_unaligned): str C_q, [dst], #16 ldp F_q, G_q, [src], #32 bic dst, dst, 15 + subs count, count, 32 adrp tmp2, L(ext_table) add tmp2, tmp2, :lo12:L(ext_table) add tmp2, tmp2, tmp1, LSL #2 ldr tmp3w, [tmp2] add tmp2, tmp2, tmp3w, SXTW br tmp2 - -#define EXT_CHUNK(shft) \ .p2align 4 ;\ + nop +#define EXT_CHUNK(shft) \ L(ext_size_ ## shft):;\ ext A_v.16b, C_v.16b, D_v.16b, 16-shft;\ ext B_v.16b, D_v.16b, E_v.16b, 16-shft;\ - subs count, count, 32;\ - b.ge 2f;\ -1:;\ - stp A_q, B_q, [dst], #32;\ ext H_v.16b, E_v.16b, F_v.16b, 16-shft;\ - ext I_v.16b, F_v.16b, G_v.16b, 16-shft;\ - stp H_q, I_q, [dst], #16;\ - add dst, dst, tmp1;\ - str G_q, [dst], #16;\ - b L(copy_long_check32);\ -2:;\ +1:;\ stp A_q, B_q, [dst], #32;\ prfm pldl1strm, [src, MEMCPY_PREFETCH_LDR];\ - ldp D_q, J_q, [src], #32;\ - ext H_v.16b, E_v.16b, F_v.16b, 16-shft;\ + ldp C_q, D_q, [src], #32;\ ext I_v.16b, F_v.16b, G_v.16b, 16-shft;\ - mov C_v.16b, G_v.16b;\ stp H_q, I_q, [dst], #32;\ + ext A_v.16b, G_v.16b, C_v.16b, 16-shft;\ + ext B_v.16b, C_v.16b, D_v.16b, 16-shft;\ ldp F_q, G_q, [src], #32;\ - ext A_v.16b, C_v.16b, D_v.16b, 16-shft;\ - ext B_v.16b, D_v.16b, J_v.16b, 16-shft;\ - mov E_v.16b, J_v.16b;\ + ext H_v.16b, D_v.16b, F_v.16b, 16-shft;\ subs count, count, 64;\ - b.ge 2b;\ - b 1b;\ + b.ge 1b;\ +2:;\ + ext I_v.16b, F_v.16b, G_v.16b, 16-shft;\ + b L(ext_tail); EXT_CHUNK(1) EXT_CHUNK(2) @@ -598,6 +591,14 @@ EXT_CHUNK(13) EXT_CHUNK(14) EXT_CHUNK(15) +L(ext_tail): + stp A_q, B_q, [dst], #32 + stp H_q, I_q, [dst], #16 + add dst, dst, tmp1 + str G_q, [dst], #16 + b L(copy_long_check32) + + END (MEMCPY) .section .rodata .p2align 4 -- cgit 1.4.1