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authorUlrich Drepper <drepper@redhat.com>2003-03-18 23:00:03 +0000
committerUlrich Drepper <drepper@redhat.com>2003-03-18 23:00:03 +0000
commita14b373c5d8d59b203511b31ff9f196692d7d7bb (patch)
tree25505dc8f1ca7f63f8b7b8b0e8d5189ab00886ee /sysdeps/powerpc/powerpc64/memcpy.S
parentee2af3e835beed665579befac90e4621fb92ba39 (diff)
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Update.
2003-03-18  Steven Munroe  <sjmunroe@us.ibm.com>

	* sysdeps/powerpc/powerpc64/memcpy.S: New file.
Diffstat (limited to 'sysdeps/powerpc/powerpc64/memcpy.S')
-rw-r--r--sysdeps/powerpc/powerpc64/memcpy.S210
1 files changed, 210 insertions, 0 deletions
diff --git a/sysdeps/powerpc/powerpc64/memcpy.S b/sysdeps/powerpc/powerpc64/memcpy.S
new file mode 100644
index 0000000000..4da5c2ae63
--- /dev/null
+++ b/sysdeps/powerpc/powerpc64/memcpy.S
@@ -0,0 +1,210 @@
+/* Optimized memcpy implementation for PowerPC64.
+   Copyright (C) 2003 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   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.  */
+
+#include <sysdep.h>
+#include <bp-sym.h>
+#include <bp-asm.h>
+
+/* __ptr_t [r3] memcpy (__ptr_t dst [r3], __ptr_t src [r4], size_t len [r5]);
+   Returns 'dst'.
+
+   Memcpy handles short copies (< 32-bytes) using an unaligned
+   word lwz/stw loop.  The tail (remaining 1-3) bytes is handled with the
+   appropriate combination of byte and halfword load/stores. There is no
+   attempt to optimize the alignment of short moves.  The 64-bit
+   implementations of POWER3 and POWER4 do a reasonable job of handling
+   unligned load/stores that do not cross 32-byte boundries.
+
+   Longer moves (>= 32-bytes) justify the effort to get at least the
+   destination doubleword (8-byte) aligned.  Further optimization is
+   posible when both source and destination are doubleword aligned.
+   Each case has a optimized unrolled loop.   */
+
+EALIGN (BP_SYM (memcpy), 5, 0)
+    cmpldi cr1,5,31
+    neg   0,3
+    std   30,-16(1)
+    std   31,-8(1)
+    rldicl. 0,0,0,61
+    mr    12,4
+    mr    31,5
+    mr    30,3
+    ble-  cr1,.L2
+    subf  31,0,5
+
+  /* Move 0-7 bytes as needed to get the destination doubleword alligned.  */
+    beq   0f
+    mtcrf 0x01,0
+1:  bf    31,2f
+    lbz   6,0(12)
+    addi  12,12,1
+    stb   6,0(3)
+    addi  3,3,1
+2:  bf    30,4f
+    lhz   6,0(12)
+    addi  12,12,2
+    sth   6,0(3)
+    addi  3,3,2
+4:  bf    29,0f
+    lwz   6,0(12)
+    addi  12,12,4
+    stw   6,0(3)
+    addi  3,3,4
+0:
+  /* Copy doublewords from source to destination, assumpting the
+     destination is aligned on a doubleword boundary.
+
+     First verify that there is > 7 bytes to copy and check if the source
+     is also doubleword aligned.  If there are < 8 bytes to copy fall
+     through to the tail byte copy code.  Otherwise if the source and
+     destination are both doubleword aligned use an optimized doubleword
+     copy loop.  Otherwise the source has a different alignment and we use
+     a load, shift, store strategy.  */
+    rldicl. 0,12,0,61
+    cmpldi cr6,31,7
+    ble-  cr6,.L2  /* less than 8 bytes left.  */
+    bne-  0,.L6   /* Source is not DW aligned.  */
+    srdi. 9,31,3
+    mr    10,3
+    mr    11,12
+
+  /* Move doublewords where destination and source are aligned.
+     Use a unrolled loop to copy 4 doubleword (32-bytes) per iteration.
+     If the remainder is >0 and < 32 bytes copy 1-3 doublewords.  */
+    cmpldi	cr1,9,4
+    beq   0f
+    mtcrf 0x01,9
+    blt   cr1,2f
+    ld    6,0(11)
+    .align  4
+4:
+    ld    7,8(11)
+    addi  9,9,-4
+    std   6,0(10)
+    ld    6,16(11)
+    std   7,8(10)
+    ld    7,24(11)
+    addi  11,11,32
+    cmpldi	cr1,9,4
+    std   6,16(10)
+    blt   cr1,3f
+    ld    6,0(11)
+    std   7,24(10)
+    addi  10,10,32
+    b     4b
+3:  std   7,24(10)
+    addi  10,10,32
+2:  bf    30,1f
+    ld    6,0(11)
+    ld    7,8(11)
+    addi  11,11,16
+    std   6,0(10)
+    std   7,8(10)
+    addi  10,10,16
+1:  bf    31,0f
+    ld    6,0(11)
+    addi  11,11,8
+    std   6,0(10)
+    addi  10,10,8
+0:
+
+.L8:
+    rldicr 0,31,0,60
+    rldicl 31,31,0,61
+    add   3,3,0
+    add   12,12,0
+
+	/* Copy the tail for up to 31 bytes.  If this is the tail of a longer
+	   copy then the destination will be aligned and the length will be
+	   less than 8.  So it is normally not worth the set-up overhead to
+	   get doubleword aligned and do doubleword load/store.  */
+.L2:
+    mr.   10,31
+    cmpldi	cr1,31,4
+    beq   0f
+    mtcrf 0x01,31
+    blt   cr1,2f
+4:  lwz   6,0(12)
+    addi  12,12,4
+    addi  10,10,-4
+    stw   6,0(3)
+    cmpldi	cr1,10,4
+    addi  3,3,4
+    bge   cr1,4b
+2:  bf    30,1f
+    lhz   6,0(12)
+    addi  12,12,2
+    sth   6,0(3)
+    addi  3,3,2
+1:  bf    31,0f
+    lbz   6,0(12)
+    addi  12,12,1
+    stb   6,0(3)
+    addi  3,3,1
+0:
+  /* Return original dst pointer.  */
+    ld 31,-8(1)
+    mr 3,30
+    ld 30,-16(1)
+    blr
+
+.L6:
+    srdi 11,31,3
+    mr 4,3
+    mr 5,12
+
+  /* Copy doublewords where the destination is aligned but the source is
+     not.  Use aligned doubleword loads from the source, shifted to realign
+     the data, to allow aligned destination stores.  */
+    andi. 10,5,7
+    andi. 0,11,1
+    subf  5,10,5
+    ld    6,0(5)
+    sldi  10,10,3
+    ld    7,8(5)
+    subfic  9,10,64
+    beq   2f
+    sld   0,6,10
+    addi  11,11,-1
+    mr    6,7
+    addi  4,4,-8
+    cmpldi  11,0
+    b     1f
+2:  addi  5,5,8
+    .align  4
+0:  sld   0,6,10
+    srd   8,7,9
+    addi  11,11,-2
+    ld    6,8(5)
+    or    0,0,8
+    cmpldi  11,0
+    std   0,0(4)
+    sld   0,7,10
+1:  srd   8,6,9
+    or    0,0,8
+    beq   8f
+    ld    7,16(5)
+    std   0,8(4)
+    addi  5,5,16
+    addi  4,4,16
+    b     0b
+8:
+    std   0,8(4)
+    b .L8
+END_GEN_TB (BP_SYM (memcpy),TB_TOCLESS)