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/* 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, 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_def (memmove)
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