243 lines
7.7 KiB
ArmAsm
243 lines
7.7 KiB
ArmAsm
/* 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
|
|
|
|
#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
|
|
.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
|
|
|
|
END(memmove)
|
|
libc_hidden_builtin_def (memmove)
|