| /* Optimized version of the standard memmove() function. |
| This file is part of the GNU C Library. |
| Copyright (C) 2000, 2001, 2003 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, write to the Free |
| Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
| 02111-1307 USA. */ |
| |
| /* 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_def (memmove) |