| /* Optimized version of the standard memmove() function. |
| This file is part of the GNU C Library. |
| Copyright (C) 2000-2018 Free Software Foundation, Inc. |
| Contributed by Dan Pop <Dan.Pop@cern.ch>. |
| |
| 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 |
| <http://www.gnu.org/licenses/>. */ |
| |
| /* Return: dest |
| |
| Inputs: |
| in0: dest |
| in1: src |
| in2: byte count |
| |
| The core of the function is the memcpy implementation used in memcpy.S. |
| When bytes have to be copied backwards, only the easy case, when |
| all arguments are multiples of 8, is optimised. |
| |
| In this form, it assumes little endian mode. For big endian mode, |
| sh1 must be computed using an extra instruction: sub sh1 = 64, sh1 |
| or the UM.be bit should be cleared at the beginning and set at the end. */ |
| |
| #include <sysdep.h> |
| #undef ret |
| |
| #define OP_T_THRES 16 |
| #define OPSIZ 8 |
| |
| #define adest r15 |
| #define saved_pr r17 |
| #define saved_lc r18 |
| #define dest r19 |
| #define src r20 |
| #define len r21 |
| #define asrc r22 |
| #define tmp2 r23 |
| #define tmp3 r24 |
| #define tmp4 r25 |
| #define ptable r26 |
| #define ploop56 r27 |
| #define loopaddr r28 |
| #define sh1 r29 |
| #define loopcnt r30 |
| #define value r31 |
| |
| #ifdef GAS_ALIGN_BREAKS_UNWIND_INFO |
| # define ALIGN(n) { nop 0 } |
| #else |
| # define ALIGN(n) .align n |
| #endif |
| |
| #define LOOP(shift) \ |
| ALIGN(32); \ |
| .loop##shift##: \ |
| (p[0]) ld8 r[0] = [asrc], 8 ; /* w1 */ \ |
| (p[MEMLAT+1]) st8 [dest] = value, 8 ; \ |
| (p[MEMLAT]) shrp value = r[MEMLAT], r[MEMLAT+1], shift ; \ |
| nop.b 0 ; \ |
| nop.b 0 ; \ |
| br.ctop.sptk .loop##shift ; \ |
| br.cond.sptk .cpyfew ; /* deal with the remaining bytes */ |
| |
| #define MEMLAT 21 |
| #define Nrot (((2*MEMLAT+3) + 7) & ~7) |
| |
| ENTRY(memmove) |
| .prologue |
| alloc r2 = ar.pfs, 3, Nrot - 3, 0, Nrot |
| .rotr r[MEMLAT + 2], q[MEMLAT + 1] |
| .rotp p[MEMLAT + 2] |
| mov ret0 = in0 // return value = dest |
| .save pr, saved_pr |
| mov saved_pr = pr // save the predicate registers |
| .save ar.lc, saved_lc |
| mov saved_lc = ar.lc // save the loop counter |
| .body |
| or tmp3 = in0, in1 ;; // tmp3 = dest | src |
| or tmp3 = tmp3, in2 // tmp3 = dest | src | len |
| mov dest = in0 // dest |
| mov src = in1 // src |
| mov len = in2 // len |
| sub tmp2 = r0, in0 // tmp2 = -dest |
| cmp.eq p6, p0 = in2, r0 // if (len == 0) |
| (p6) br.cond.spnt .restore_and_exit;;// return dest; |
| and tmp4 = 7, tmp3 // tmp4 = (dest | src | len) & 7 |
| cmp.le p6, p0 = dest, src // if dest <= src it's always safe |
| (p6) br.cond.spnt .forward // to copy forward |
| add tmp3 = src, len;; |
| cmp.lt p6, p0 = dest, tmp3 // if dest > src && dest < src + len |
| (p6) br.cond.spnt .backward // we have to copy backward |
| |
| .forward: |
| shr.u loopcnt = len, 4 ;; // loopcnt = len / 16 |
| cmp.ne p6, p0 = tmp4, r0 // if ((dest | src | len) & 7 != 0) |
| (p6) br.cond.sptk .next // goto next; |
| |
| // The optimal case, when dest, src and len are all multiples of 8 |
| |
| and tmp3 = 0xf, len |
| mov pr.rot = 1 << 16 // set rotating predicates |
| mov ar.ec = MEMLAT + 1 ;; // set the epilog counter |
| cmp.ne p6, p0 = tmp3, r0 // do we have to copy an extra word? |
| adds loopcnt = -1, loopcnt;; // --loopcnt |
| (p6) ld8 value = [src], 8;; |
| (p6) st8 [dest] = value, 8 // copy the "odd" word |
| mov ar.lc = loopcnt // set the loop counter |
| cmp.eq p6, p0 = 8, len |
| (p6) br.cond.spnt .restore_and_exit;;// the one-word special case |
| adds adest = 8, dest // set adest one word ahead of dest |
| adds asrc = 8, src ;; // set asrc one word ahead of src |
| nop.b 0 // get the "golden" alignment for |
| nop.b 0 // the next loop |
| .l0: |
| (p[0]) ld8 r[0] = [src], 16 |
| (p[0]) ld8 q[0] = [asrc], 16 |
| (p[MEMLAT]) st8 [dest] = r[MEMLAT], 16 |
| (p[MEMLAT]) st8 [adest] = q[MEMLAT], 16 |
| br.ctop.dptk .l0 ;; |
| |
| mov pr = saved_pr, -1 // restore the predicate registers |
| mov ar.lc = saved_lc // restore the loop counter |
| br.ret.sptk.many b0 |
| .next: |
| cmp.ge p6, p0 = OP_T_THRES, len // is len <= OP_T_THRES |
| and loopcnt = 7, tmp2 // loopcnt = -dest % 8 |
| (p6) br.cond.spnt .cpyfew // copy byte by byte |
| ;; |
| cmp.eq p6, p0 = loopcnt, r0 |
| (p6) br.cond.sptk .dest_aligned |
| sub len = len, loopcnt // len -= -dest % 8 |
| adds loopcnt = -1, loopcnt // --loopcnt |
| ;; |
| mov ar.lc = loopcnt |
| .l1: // copy -dest % 8 bytes |
| ld1 value = [src], 1 // value = *src++ |
| ;; |
| st1 [dest] = value, 1 // *dest++ = value |
| br.cloop.dptk .l1 |
| .dest_aligned: |
| and sh1 = 7, src // sh1 = src % 8 |
| and tmp2 = -8, len // tmp2 = len & -OPSIZ |
| and asrc = -8, src // asrc = src & -OPSIZ -- align src |
| shr.u loopcnt = len, 3 // loopcnt = len / 8 |
| and len = 7, len;; // len = len % 8 |
| adds loopcnt = -1, loopcnt // --loopcnt |
| addl tmp4 = @ltoff(.table), gp |
| addl tmp3 = @ltoff(.loop56), gp |
| mov ar.ec = MEMLAT + 1 // set EC |
| mov pr.rot = 1 << 16;; // set rotating predicates |
| mov ar.lc = loopcnt // set LC |
| cmp.eq p6, p0 = sh1, r0 // is the src aligned? |
| (p6) br.cond.sptk .src_aligned |
| add src = src, tmp2 // src += len & -OPSIZ |
| shl sh1 = sh1, 3 // sh1 = 8 * (src % 8) |
| ld8 ploop56 = [tmp3] // ploop56 = &loop56 |
| ld8 ptable = [tmp4];; // ptable = &table |
| add tmp3 = ptable, sh1;; // tmp3 = &table + sh1 |
| mov ar.ec = MEMLAT + 1 + 1 // one more pass needed |
| ld8 tmp4 = [tmp3];; // tmp4 = loop offset |
| sub loopaddr = ploop56,tmp4 // loopadd = &loop56 - loop offset |
| ld8 r[1] = [asrc], 8;; // w0 |
| mov b6 = loopaddr;; |
| br b6 // jump to the appropriate loop |
| |
| LOOP(8) |
| LOOP(16) |
| LOOP(24) |
| LOOP(32) |
| LOOP(40) |
| LOOP(48) |
| LOOP(56) |
| |
| .src_aligned: |
| .l3: |
| (p[0]) ld8 r[0] = [src], 8 |
| (p[MEMLAT]) st8 [dest] = r[MEMLAT], 8 |
| br.ctop.dptk .l3 |
| .cpyfew: |
| cmp.eq p6, p0 = len, r0 // is len == 0 ? |
| adds len = -1, len // --len; |
| (p6) br.cond.spnt .restore_and_exit ;; |
| mov ar.lc = len |
| .l4: |
| ld1 value = [src], 1 |
| ;; |
| st1 [dest] = value, 1 |
| br.cloop.dptk .l4 ;; |
| .restore_and_exit: |
| mov pr = saved_pr, -1 // restore the predicate registers |
| mov ar.lc = saved_lc // restore the loop counter |
| br.ret.sptk.many b0 |
| |
| // In the case of a backward copy, optimise only the case when everything |
| // is a multiple of 8, otherwise copy byte by byte. The backward copy is |
| // used only when the blocks are overlapping and dest > src. |
| |
| .backward: |
| shr.u loopcnt = len, 3 // loopcnt = len / 8 |
| add src = src, len // src points one byte past the end |
| add dest = dest, len ;; // dest points one byte past the end |
| mov ar.ec = MEMLAT + 1 // set the epilog counter |
| mov pr.rot = 1 << 16 // set rotating predicates |
| adds loopcnt = -1, loopcnt // --loopcnt |
| cmp.ne p6, p0 = tmp4, r0 // if ((dest | src | len) & 7 != 0) |
| (p6) br.cond.sptk .bytecopy ;; // copy byte by byte backward |
| adds src = -8, src // src points to the last word |
| adds dest = -8, dest // dest points to the last word |
| mov ar.lc = loopcnt;; // set the loop counter |
| .l5: |
| (p[0]) ld8 r[0] = [src], -8 |
| (p[MEMLAT]) st8 [dest] = r[MEMLAT], -8 |
| br.ctop.dptk .l5 |
| br.cond.sptk .restore_and_exit |
| .bytecopy: |
| adds src = -1, src // src points to the last byte |
| adds dest = -1, dest // dest points to the last byte |
| adds loopcnt = -1, len;; // loopcnt = len - 1 |
| mov ar.lc = loopcnt;; // set the loop counter |
| .l6: |
| (p[0]) ld1 r[0] = [src], -1 |
| (p[MEMLAT]) st1 [dest] = r[MEMLAT], -1 |
| br.ctop.dptk .l6 |
| br.cond.sptk .restore_and_exit |
| END(memmove) |
| |
| .rodata |
| .align 8 |
| .table: |
| data8 0 // dummy entry |
| data8 .loop56 - .loop8 |
| data8 .loop56 - .loop16 |
| data8 .loop56 - .loop24 |
| data8 .loop56 - .loop32 |
| data8 .loop56 - .loop40 |
| data8 .loop56 - .loop48 |
| data8 .loop56 - .loop56 |
| |
| libc_hidden_builtin_def (memmove) |