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-rw-r--r--sysdeps/powerpc/powerpc64/power6/memcpy.S1170
1 files changed, 1170 insertions, 0 deletions
diff --git a/sysdeps/powerpc/powerpc64/power6/memcpy.S b/sysdeps/powerpc/powerpc64/power6/memcpy.S
new file mode 100644
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+++ b/sysdeps/powerpc/powerpc64/power6/memcpy.S
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+/* Optimized memcpy implementation for PowerPC64.
+   Copyright (C) 2003, 2006, 2007 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., 51 Franklin Street, Fifth Floor, Boston MA
+   02110-1301 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 a binary move blocks 
+   (no loops) of lwz/stw.  The tail (remaining 1-3) bytes is handled 
+   with the appropriate combination of byte and halfword load/stores. 
+   There is minimal effort 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.  
+     
+   For POWER6 unaligned loads will take a 20+ cycle hicup for any
+   L1 cache miss that crosses a 32- or 128-byte boundary.  Store
+   is more forgiving and does not take a hicup until page or 
+   segment boundaries.  So we require doubleword alignment for 
+   the source but may take a risk and only require word alignment
+   for the destination.  */
+
+	.machine	"power6"
+EALIGN (BP_SYM (memcpy), 7, 0)
+	CALL_MCOUNT 3
+
+    cmpldi cr1,5,31
+    neg   0,3
+    std   3,-16(1)
+    std   31,-8(1)
+    andi. 11,3,7	/* check alignement of dst.  */
+    clrldi 0,0,61	/* Number of bytes until the 1st doubleword of dst.  */
+    clrldi 10,4,61	/* check alignement of src.  */
+    cmpldi cr6,5,8
+    ble-  cr1,.L2	/* If move < 32 bytes use short move code.  */
+    mtcrf 0x01,0
+    cmpld cr6,10,11  
+    srdi  9,5,3		/* Number of full double words remaining.  */
+    beq   .L0
+  
+    subf  5,0,5
+  /* Move 0-7 bytes as needed to get the destination doubleword alligned.
+     Duplicate some code to maximize fall-throught and minimize agen delays.  */
+1:  bf    31,2f
+    lbz   6,0(4)
+    stb   6,0(3)
+    bf    30,5f
+    lhz   6,1(4)
+    sth   6,1(3)
+    bf    29,0f
+    lwz   6,3(4)
+    stw   6,3(3)
+    b     0f
+5:
+    bf    29,0f
+    lwz   6,1(4)
+    stw   6,1(3)
+    b     0f
+    
+2:  bf    30,4f
+    lhz   6,0(4)
+    sth   6,0(3)
+    bf    29,0f
+    lwz   6,2(4)
+    stw   6,2(3)
+    b     0f
+    
+4:  bf    29,0f
+    lwz   6,0(4)
+    stw   6,0(3)
+0: 
+/* Add the number of bytes until the 1st doubleword of dst to src and dst.  */
+    add   4,4,0
+    add   3,3,0
+    
+    clrldi 10,4,61	/* check alignement of src again.  */     
+    srdi  9,5,3	/* Number of full double words remaining.  */
+    
+  /* Copy doublewords from source to destination, assumpting the
+     destination is aligned on a doubleword boundary.
+
+     At this point we know there are at least 25 bytes left (32-7) to copy.
+     The next step is to determine if the source is also doubleword aligned. 
+     If not branch to the unaligned move code at .L6. which uses
+     a load, shift, store strategy.
+     
+     Otherwise source and destination are doubleword aligned, and we can
+     the optimized doubleword copy loop.  */
+    .align  4
+.L0:
+    clrldi  11,5,61
+    andi.   0,5,0x78
+    srdi    12,5,7	/* Number of 128-byte blocks to move.  */
+    cmpldi  cr1,11,0	/* If the tail is 0 bytes  */
+    bne-    cr6,.L6     /* If source is not DW aligned.  */
+
+  /* Move doublewords where destination and source are DW aligned.
+     Use a unrolled loop to copy 16 doublewords (128-bytes) per iteration.
+     If the the copy is not an exact multiple of 128 bytes, 1-15
+     doublewords are copied as needed to set up the main loop.  After
+     the main loop exits there may be a tail of 1-7 bytes. These byte
+     are copied a word/halfword/byte at a time as needed to preserve
+     alignment.
+     
+     For POWER6 the L1 is store-through and the L2 is store-in.  The
+     L2 is clocked at half CPU clock so we can store 16 bytes every
+     other cycle.  POWER6 also has a load/store bypass so we can do
+     load, load, store, store every 2 cycles.  
+     
+     The following code is sensitive to cache line alignment.  Do not
+     make any change with out first making sure thay don't result in
+     splitting ld/std pairs across a cache line.  */
+
+    mtcrf 0x02,5
+    mtcrf 0x01,5
+    cmpldi  cr5,12,1
+    beq   L(das_loop)
+
+    bf    25,4f
+    .align  3
+    ld    6,0(4)
+    ld    7,8(4)
+    mr    11,4
+    mr    10,3
+    std   6,0(3)
+    std   7,8(3)
+    ld    6,16(4)
+    ld    7,24(4)
+    std   6,16(3)
+    std   7,24(3)
+    ld    6,0+32(4)
+    ld    7,8+32(4)
+    addi  4,4,64
+    addi  3,3,64
+    std   6,0+32(10)
+    std   7,8+32(10)
+    ld    6,16+32(11)
+    ld    7,24+32(11)
+    std   6,16+32(10)
+    std   7,24+32(10)
+4:
+    mr    10,3
+    bf    26,2f
+    ld    6,0(4)
+    ld    7,8(4)
+    mr    11,4
+    nop
+    std   6,0(3)
+    std   7,8(3)
+    ld    6,16(4)
+    ld    7,24(4)
+    addi  4,4,32
+    std   6,16(3)
+    std   7,24(3)
+    addi  3,3,32
+6:
+    nop
+    bf    27,5f
+    ld    6,0+32(11)
+    ld    7,8+32(11)
+    addi  4,4,16
+    addi  3,3,16
+    std   6,0+32(10)
+    std   7,8+32(10)
+    bf    28,L(das_loop_s)
+    ld    0,16+32(11)
+    addi  4,4,8
+    addi  3,3,8
+    std   0,16+32(10)
+    blt   cr5,L(das_tail)
+    b     L(das_loop)
+    .align  3
+5:
+    nop
+    bf    28,L(das_loop_s)
+    ld    6,32(11)
+    addi  4,4,8
+    addi  3,3,8
+    std   6,32(10)
+    blt   cr5,L(das_tail)
+    b     L(das_loop)
+    .align  3
+2:
+    mr    11,4
+    bf    27,1f
+    ld    6,0(4)
+    ld    7,8(4)
+    addi  4,4,16
+    addi  3,3,16
+    std   6,0(10)
+    std   7,8(10)
+    bf    28,L(das_loop_s)
+    ld    0,16(11)
+    addi  4,11,24
+    addi  3,10,24
+    std   0,16(10)
+    blt   cr5,L(das_tail)
+    b     L(das_loop)
+    .align  3
+1:
+    nop
+    bf    28,L(das_loop_s)
+    ld    6,0(4)
+    addi  4,4,8
+    addi  3,3,8
+    std   6,0(10)
+L(das_loop_s):
+    nop
+    blt   cr5,L(das_tail)
+    .align  4
+L(das_loop):
+    ld    6,0(4)
+    ld    7,8(4)
+    mr    10,3
+    mr    11,4
+    std   6,0(3)
+    std   7,8(3)
+    addi  12,12,-1
+    nop
+    ld    8,16(4)
+    ld    0,24(4)
+    std   8,16(3)
+    std   0,24(3)
+
+    ld    6,0+32(4)
+    ld    7,8+32(4)
+    std   6,0+32(3)
+    std   7,8+32(3)
+    ld    8,16+32(4)
+    ld    0,24+32(4)
+    std   8,16+32(3)
+    std   0,24+32(3)
+
+    ld    6,0+64(11)
+    ld    7,8+64(11)
+    std   6,0+64(10)
+    std   7,8+64(10)
+    ld    8,16+64(11)
+    ld    0,24+64(11)
+    std   8,16+64(10)
+    std   0,24+64(10)
+
+    ld    6,0+96(11)
+    ld    7,8+96(11)
+    addi  4,4,128
+    addi  3,3,128
+    std   6,0+96(10)
+    std   7,8+96(10)
+    ld    8,16+96(11)
+    ld    0,24+96(11)
+    std   8,16+96(10)
+    std   0,24+96(10)
+    ble   cr5,L(das_loop_e)
+    
+    mtctr   12
+    .align  4
+L(das_loop2):
+    ld    6,0(4)
+    ld    7,8(4)
+    mr    10,3
+    mr    11,4
+    std   6,0(3)
+    std   7,8(3)
+    ld    8,16(4)
+    ld    0,24(4)
+    std   8,16(3)
+    std   0,24(3)
+
+    ld    6,0+32(4)
+    ld    7,8+32(4)
+    std   6,0+32(3)
+    std   7,8+32(3)
+    ld    8,16+32(4)
+    ld    0,24+32(4)
+    std   8,16+32(3)
+    std   0,24+32(3)
+
+    ld    6,0+64(11)
+    ld    7,8+64(11)
+    std   6,0+64(10)
+    std   7,8+64(10)
+    ld    8,16+64(11)
+    ld    0,24+64(11)
+    std   8,16+64(10)
+    std   0,24+64(10)
+
+    ld    6,0+96(11)
+    ld    7,8+96(11)
+    addi  4,4,128
+    addi  3,3,128
+    std   6,0+96(10)
+    std   7,8+96(10)
+    ld    8,16+96(11)
+    ld    0,24+96(11)
+    std   8,16+96(10)
+    std   0,24+96(10)
+    bdnz  L(das_loop2)
+L(das_loop_e):
+/* Check of a 1-7 byte tail, return if none.  */
+    bne   cr1,L(das_tail2)
+/* Return original dst pointer.  */
+    ld 3,-16(1)
+    blr
+    .align  4
+L(das_tail):
+    beq   cr1,0f
+    
+L(das_tail2):
+/*  At this point we have a tail of 0-7 bytes and we know that the
+    destiniation is double word aligned.  */
+4:  bf    29,2f
+    lwz   6,0(4)
+    stw   6,0(3)
+    bf    30,5f
+    lhz   6,4(4)
+    sth   6,4(3)
+    bf    31,0f
+    lbz   6,6(4)
+    stb   6,6(3)
+    b     0f
+5:  bf    31,0f
+    lbz   6,4(4)
+    stb   6,4(3)
+    b     0f
+  
+2:  bf    30,1f
+    lhz   6,0(4)
+    sth   6,0(3)
+    bf    31,0f
+    lbz   6,2(4)
+    stb   6,2(3)
+    b     0f
+    
+1:  bf    31,0f
+    lbz   6,0(4)
+    stb   6,0(3)
+0:
+  /* Return original dst pointer.  */
+    ld 3,-16(1)
+    blr
+
+/* Copy up to 31 bytes.  This divided into two cases 0-8 bytes and 9-31 
+   bytes.  Each case is handled without loops, using binary (1,2,4,8)
+   tests.
+
+   In the short (0-8 byte) case no attempt is made to force alignment
+   of either source or destination.  The hardware will handle the
+   unaligned load/stores with small delays for crossing 32- 128-byte,
+   and 4096-byte boundaries. Since these short moves are unlikely to be
+   unaligned or cross these boundaries, the overhead to force
+   alignment is not justified.
+
+   The longer (9-31 byte) move is more likely to cross 32- or 128-byte
+   boundaries.  Since only loads are sensitive to the 32-/128-byte
+   boundaries it is more important to align the source then the
+   destination.  If the source is not already word aligned, we first
+   move 1-3 bytes as needed.  Since we are only word aligned we don't
+   use double word load/stores to insure that all loads are aligned.
+   While the destination and stores may still be unaligned, this
+   is only an issue for page (4096 byte boundary) crossing, which
+   should be rare for these short moves.  The hardware handles this
+   case automatically with a small (~20 cycle) delay.  */
+    .align  4
+.L2:
+    mtcrf 0x01,5
+    neg   8,4
+    clrrdi	11,4,2
+    andi. 0,8,3
+    ble   cr6,.LE8	/* Handle moves of 0-8 bytes.  */
+/* At least 9 bytes left.  Get the source word aligned.  */
+    cmpldi	cr1,5,16
+    mr    10,5
+    mr    12,4
+    cmpldi	cr6,0,2
+    beq   L(dus_tail)	/* If the source is already word aligned skip this.  */
+/* Copy 1-3 bytes to get source address word aligned.  */
+    lwz   6,0(11)
+    subf  10,0,5
+    add   12,4,0
+    blt   cr6,5f
+    srdi  7,6,16
+    bgt	  cr6,3f
+    sth   6,0(3)
+    b     7f
+    .align  4
+3:
+    stb   7,0(3)
+    sth   6,1(3)
+    b     7f
+    .align  4
+5:
+    stb   6,0(3)
+7:
+    cmpldi	cr1,10,16
+    add   3,3,0
+    mtcrf 0x01,10
+    .align  4
+L(dus_tail):
+/* At least 6 bytes left and the source is word aligned.  This allows
+   some speculative loads up front.  */
+/* We need to special case the fall-through because the biggest delays
+   are due to address computation not being ready in time for the 
+   AGEN.  */
+    lwz   6,0(12)
+    lwz   7,4(12)
+    blt   cr1,L(dus_tail8)
+    cmpldi	cr0,10,24
+L(dus_tail16): /* Move 16 bytes.  */
+    stw   6,0(3)
+    stw   7,4(3)
+    lwz   6,8(12)
+    lwz   7,12(12)
+    stw   6,8(3)
+    stw   7,12(3)
+/* Move 8 bytes more.  */
+    bf    28,L(dus_tail16p8)
+    cmpldi	cr1,10,28
+    lwz   6,16(12)
+    lwz   7,20(12)
+    stw   6,16(3)
+    stw   7,20(3)
+/* Move 4 bytes more.  */
+    bf    29,L(dus_tail16p4)
+    lwz   6,24(12)
+    stw   6,24(3)
+    addi  12,12,28
+    addi  3,3,28
+    bgt   cr1,L(dus_tail2)
+ /* exactly 28 bytes.  Return original dst pointer and exit.  */
+    ld    3,-16(1)
+    blr
+    .align  4
+L(dus_tail16p8):  /* less then 8 bytes left.  */
+    beq   cr1,L(dus_tailX) /* exactly 16 bytes, early exit.  */
+    cmpldi	cr1,10,20
+    bf    29,L(dus_tail16p2)
+/* Move 4 bytes more.  */
+    lwz   6,16(12)
+    stw   6,16(3)
+    addi  12,12,20
+    addi  3,3,20
+    bgt   cr1,L(dus_tail2)
+ /* exactly 20 bytes.  Return original dst pointer and exit.  */
+    ld    3,-16(1)
+    blr
+    .align  4
+L(dus_tail16p4):  /* less then 4 bytes left.  */
+    addi  12,12,24
+    addi  3,3,24
+    bgt   cr0,L(dus_tail2)
+ /* exactly 24 bytes.  Return original dst pointer and exit.  */
+    ld    3,-16(1)
+    blr
+    .align  4
+L(dus_tail16p2):  /* 16 bytes moved, less then 4 bytes left.  */
+    addi  12,12,16
+    addi  3,3,16
+    b     L(dus_tail2)
+
+    .align  4
+L(dus_tail8):  /* Move 8 bytes.  */
+/*  r6, r7 already loaded speculatively.  */
+    cmpldi	cr1,10,8
+    cmpldi	cr0,10,12
+    bf    28,L(dus_tail4)
+    .align  2
+    stw   6,0(3)
+    stw   7,4(3)
+/* Move 4 bytes more.  */
+    bf    29,L(dus_tail8p4)
+    lwz   6,8(12)
+    stw   6,8(3)
+    addi  12,12,12
+    addi  3,3,12
+    bgt   cr0,L(dus_tail2)
+ /* exactly 12 bytes.  Return original dst pointer and exit.  */
+    ld    3,-16(1)
+    blr
+    .align  4
+L(dus_tail8p4):  /* less then 4 bytes left.  */
+    addi  12,12,8
+    addi  3,3,8
+    bgt   cr1,L(dus_tail2)
+ /* exactly 8 bytes.  Return original dst pointer and exit.  */
+    ld    3,-16(1)
+    blr
+
+    .align  4
+L(dus_tail4):  /* Move 4 bytes.  */
+/*  r6 already loaded speculatively.  If we are here we know there is
+    more then 4 bytes left.  So there is no need to test.  */
+    addi  12,12,4
+    stw   6,0(3)
+    addi  3,3,4
+L(dus_tail2):  /* Move 2-3 bytes.  */
+    bf    30,L(dus_tail1)
+    lhz   6,0(12)
+    sth   6,0(3) 
+    bf    31,L(dus_tailX)
+    lbz   7,2(12)
+    stb   7,2(3)
+    ld 3,-16(1)
+    blr
+L(dus_tail1):  /* Move 1 byte.  */
+    bf    31,L(dus_tailX)
+    lbz   6,0(12)
+    stb   6,0(3)
+L(dus_tailX):
+  /* Return original dst pointer.  */
+    ld    3,-16(1)
+    blr
+
+/* Special case to copy 0-8 bytes.  */
+    .align  4
+.LE8:
+    mr    12,4
+    bne   cr6,L(dus_4)
+/* Exactly 8 bytes.  We may cross a 32-/128-byte boundry and take a ~20
+   cycle delay.  This case should be rare and any attempt to avoid this
+   would take most of 20 cycles any way.  */
+    ld   6,0(4)
+    std   6,0(3)
+  /* Return original dst pointer.  */
+    ld    3,-16(1)
+    blr
+    .align  4
+L(dus_4):
+    bf    29,L(dus_tail2)
+    lwz   6,0(4)
+    stw   6,0(3)
+    bf    30,L(dus_5)
+    lhz   7,4(4)
+    sth   7,4(3) 
+    bf    31,L(dus_0)
+    lbz   8,6(4)
+    stb   8,6(3)
+    ld 3,-16(1)
+    blr
+    .align  4
+L(dus_5):
+    bf    31,L(dus_0)
+    lbz   6,4(4)
+    stb   6,4(3)
+L(dus_0):
+  /* Return original dst pointer.  */
+    ld    3,-16(1)
+    blr
+
+    .align  4
+.L6:
+    cfi_offset(31,-8)
+    mr    12,4
+    mr    31,5
+  /* 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.  */
+    addi    11,9,-1  /* loop DW count is one less than total */
+    subf    5,10,12  /* Move source addr to previous full double word.  */
+    cmpldi  cr5, 10, 2
+    cmpldi  cr0, 10, 4
+    mr      4,3
+    srdi    8,11,2   /* calculate the 32 byte loop count */
+    ld      6,0(5)   /* pre load 1st full doubleword.  */
+    mtcrf   0x01,11
+    cmpldi  cr6,9,4
+    mtctr   8
+    ld      7,8(5)   /* pre load 2nd full doubleword.  */
+    bge     cr0, L(du4_do)
+    blt     cr5, L(du1_do)
+    beq     cr5, L(du2_do)
+    b       L(du3_do) 
+       
+    .align 4
+L(du1_do):
+    bf      30,L(du1_1dw)
+
+    /* there are at least two DWs to copy */
+    sldi     0,6, 8
+    srdi     8,7, 64-8
+    or      0,0,8
+    ld      6,16(5)
+    std     0,0(4)
+    sldi     0,7, 8
+    srdi     8,6, 64-8
+    or      0,0,8
+    ld      7,24(5)
+    std     0,8(4)
+    addi    4,4,16
+    addi    5,5,32
+    blt     cr6,L(du1_fini)  /* if total DWs = 3, then bypass loop */
+    bf      31,L(du1_loop)
+    /* there is a third DW to copy */
+    sldi     0,6, 8
+    srdi     8,7, 64-8
+    or      0,0,8
+    std     0,0(4)
+    mr      6,7
+    ld      7,0(5)
+    addi    5,5,8
+    addi    4,4,8
+    beq     cr6,L(du1_fini)  /* if total DWs = 4, then bypass loop */
+    b       L(du1_loop)
+    .align 4
+L(du1_1dw):
+    sldi     0,6, 8
+    srdi     8,7, 64-8
+    addi    5,5,16
+    or      0,0,8
+    bf      31,L(du1_loop)
+    mr      6,7
+    ld      7,0(5)
+    addi    5,5,8
+    std     0,0(4)
+    addi    4,4,8
+    .align 4
+/* copy 32 bytes at a time */
+L(du1_loop):
+    sldi   0,6, 8
+    srdi   8,7, 64-8
+    or    0,0,8
+    ld    6,0(5)
+    std   0,0(4)
+    sldi   0,7, 8
+    srdi   8,6, 64-8
+    or    0,0,8
+    ld    7,8(5)
+    std   0,8(4)
+    sldi   0,6, 8
+    srdi   8,7, 64-8
+    or    0,0,8
+    ld    6,16(5)
+    std   0,16(4)
+    sldi   0,7, 8
+    srdi   8,6, 64-8
+    or    0,0,8
+    ld    7,24(5)
+    std   0,24(4)
+    addi  5,5,32
+    addi  4,4,32
+    bdnz+ L(du1_loop)
+    .align 4
+L(du1_fini):
+    /* calculate and store the final DW */
+    sldi   0,6, 8
+    srdi   8,7, 64-8
+    or    0,0,8  
+    std   0,0(4)
+    b     L(du_done)
+
+    .align 4
+L(du2_do):
+    bf      30,L(du2_1dw)
+
+    /* there are at least two DWs to copy */
+    sldi     0,6, 16
+    srdi     8,7, 64-16
+    or      0,0,8
+    ld      6,16(5)
+    std     0,0(4)
+    sldi     0,7, 16
+    srdi     8,6, 64-16
+    or      0,0,8
+    ld      7,24(5)
+    std     0,8(4)
+    addi    4,4,16
+    addi    5,5,32
+    blt     cr6,L(du2_fini)  /* if total DWs = 3, then bypass loop */
+    bf      31,L(du2_loop)
+    /* there is a third DW to copy */
+    sldi     0,6, 16
+    srdi     8,7, 64-16
+    or      0,0,8
+    std     0,0(4)
+    mr      6,7
+    ld      7,0(5)
+    addi    5,5,8
+    addi    4,4,8
+    beq     cr6,L(du2_fini)  /* if total DWs = 4, then bypass loop */
+    b       L(du2_loop)
+    .align 4
+L(du2_1dw):
+    sldi     0,6, 16
+    srdi     8,7, 64-16
+    addi    5,5,16
+    or      0,0,8
+    bf      31,L(du2_loop)
+    mr      6,7
+    ld      7,0(5)
+    addi    5,5,8
+    std     0,0(4)
+    addi    4,4,8
+    .align 4
+/* copy 32 bytes at a time */
+L(du2_loop):
+    sldi   0,6, 16
+    srdi   8,7, 64-16
+    or    0,0,8
+    ld    6,0(5)
+    std   0,0(4)
+    sldi   0,7, 16
+    srdi   8,6, 64-16
+    or    0,0,8
+    ld    7,8(5)
+    std   0,8(4)
+    sldi   0,6, 16
+    srdi   8,7, 64-16
+    or    0,0,8
+    ld    6,16(5)
+    std   0,16(4)
+    sldi   0,7, 16
+    srdi   8,6, 64-16
+    or    0,0,8
+    ld    7,24(5)
+    std   0,24(4)
+    addi  5,5,32
+    addi  4,4,32
+    bdnz+ L(du2_loop)
+    .align 4
+L(du2_fini):
+    /* calculate and store the final DW */
+    sldi   0,6, 16
+    srdi   8,7, 64-16
+    or    0,0,8  
+    std   0,0(4)
+    b     L(du_done)
+
+    .align 4
+L(du3_do):
+    bf      30,L(du3_1dw)
+
+    /* there are at least two DWs to copy */
+    sldi     0,6, 24
+    srdi     8,7, 64-24
+    or      0,0,8
+    ld      6,16(5)
+    std     0,0(4)
+    sldi     0,7, 24
+    srdi     8,6, 64-24
+    or      0,0,8
+    ld      7,24(5)
+    std     0,8(4)
+    addi    4,4,16
+    addi    5,5,32
+    blt     cr6,L(du3_fini)  /* if total DWs = 3, then bypass loop */
+    bf      31,L(du3_loop)
+    /* there is a third DW to copy */
+    sldi     0,6, 24
+    srdi     8,7, 64-24
+    or      0,0,8
+    std     0,0(4)
+    mr      6,7
+    ld      7,0(5)
+    addi    5,5,8
+    addi    4,4,8
+    beq     cr6,L(du3_fini)  /* if total DWs = 4, then bypass loop */
+    b       L(du3_loop)
+    .align 4
+L(du3_1dw):
+    sldi     0,6, 24
+    srdi     8,7, 64-24
+    addi    5,5,16
+    or      0,0,8
+    bf      31,L(du3_loop)
+    mr      6,7
+    ld      7,0(5)
+    addi    5,5,8
+    std     0,0(4)
+    addi    4,4,8
+    .align 4
+/* copy 32 bytes at a time */
+L(du3_loop):
+    sldi   0,6, 24
+    srdi   8,7, 64-24
+    or    0,0,8
+    ld    6,0(5)
+    std   0,0(4)
+    sldi   0,7, 24
+    srdi   8,6, 64-24
+    or    0,0,8
+    ld    7,8(5)
+    std   0,8(4)
+    sldi   0,6, 24
+    srdi   8,7, 64-24
+    or    0,0,8
+    ld    6,16(5)
+    std   0,16(4)
+    sldi   0,7, 24
+    srdi   8,6, 64-24
+    or    0,0,8
+    ld    7,24(5)
+    std   0,24(4)
+    addi  5,5,32
+    addi  4,4,32
+    bdnz+ L(du3_loop)
+    .align 4
+L(du3_fini):
+    /* calculate and store the final DW */
+    sldi   0,6, 24
+    srdi   8,7, 64-24
+    or    0,0,8  
+    std   0,0(4)
+    b     L(du_done)
+
+    .align 4
+L(du4_do):
+    cmpldi  cr5, 10, 6
+    beq     cr0, L(du4_dox)
+    blt     cr5, L(du5_do)
+    beq     cr5, L(du6_do)
+    b       L(du7_do)
+L(du4_dox):
+    bf      30,L(du4_1dw)
+
+    /* there are at least two DWs to copy */
+    sldi     0,6, 32
+    srdi     8,7, 64-32
+    or      0,0,8
+    ld      6,16(5)
+    std     0,0(4)
+    sldi     0,7, 32
+    srdi     8,6, 64-32
+    or      0,0,8
+    ld      7,24(5)
+    std     0,8(4)
+    addi    4,4,16
+    addi    5,5,32
+    blt     cr6,L(du4_fini)  /* if total DWs = 3, then bypass loop */
+    bf      31,L(du4_loop)
+    /* there is a third DW to copy */
+    sldi     0,6, 32
+    srdi     8,7, 64-32
+    or      0,0,8
+    std     0,0(4)
+    mr      6,7
+    ld      7,0(5)
+    addi    5,5,8
+    addi    4,4,8
+    beq     cr6,L(du4_fini)  /* if total DWs = 4, then bypass loop */
+    b       L(du4_loop)
+    .align 4
+L(du4_1dw):
+    sldi     0,6, 32
+    srdi     8,7, 64-32
+    addi    5,5,16
+    or      0,0,8
+    bf      31,L(du4_loop)
+    mr      6,7
+    ld      7,0(5)
+    addi    5,5,8
+    std     0,0(4)
+    addi    4,4,8
+    .align 4
+/* copy 32 bytes at a time */
+L(du4_loop):
+    sldi   0,6, 32
+    srdi   8,7, 64-32
+    or    0,0,8
+    ld    6,0(5)
+    std   0,0(4)
+    sldi   0,7, 32
+    srdi   8,6, 64-32
+    or    0,0,8
+    ld    7,8(5)
+    std   0,8(4)
+    sldi   0,6, 32
+    srdi   8,7, 64-32
+    or    0,0,8
+    ld    6,16(5)
+    std   0,16(4)
+    sldi   0,7, 32
+    srdi   8,6, 64-32
+    or    0,0,8
+    ld    7,24(5)
+    std   0,24(4)
+    addi  5,5,32
+    addi  4,4,32
+    bdnz+ L(du4_loop)
+    .align 4
+L(du4_fini):
+    /* calculate and store the final DW */
+    sldi   0,6, 32
+    srdi   8,7, 64-32
+    or    0,0,8  
+    std   0,0(4)
+    b     L(du_done)
+
+    .align 4
+L(du5_do):
+    bf      30,L(du5_1dw)
+
+    /* there are at least two DWs to copy */
+    sldi     0,6, 40
+    srdi     8,7, 64-40
+    or      0,0,8
+    ld      6,16(5)
+    std     0,0(4)
+    sldi     0,7, 40
+    srdi     8,6, 64-40
+    or      0,0,8
+    ld      7,24(5)
+    std     0,8(4)
+    addi    4,4,16
+    addi    5,5,32
+    blt     cr6,L(du5_fini)  /* if total DWs = 3, then bypass loop */
+    bf      31,L(du5_loop)
+    /* there is a third DW to copy */
+    sldi     0,6, 40
+    srdi     8,7, 64-40
+    or      0,0,8
+    std     0,0(4)
+    mr      6,7
+    ld      7,0(5)
+    addi    5,5,8
+    addi    4,4,8
+    beq     cr6,L(du5_fini)  /* if total DWs = 4, then bypass loop */
+    b       L(du5_loop)
+    .align 4
+L(du5_1dw):
+    sldi     0,6, 40
+    srdi     8,7, 64-40
+    addi    5,5,16
+    or      0,0,8
+    bf      31,L(du5_loop)
+    mr      6,7
+    ld      7,0(5)
+    addi    5,5,8
+    std     0,0(4)
+    addi    4,4,8
+    .align 4
+/* copy 32 bytes at a time */
+L(du5_loop):
+    sldi   0,6, 40
+    srdi   8,7, 64-40
+    or    0,0,8
+    ld    6,0(5)
+    std   0,0(4)
+    sldi   0,7, 40
+    srdi   8,6, 64-40
+    or    0,0,8
+    ld    7,8(5)
+    std   0,8(4)
+    sldi   0,6, 40
+    srdi   8,7, 64-40
+    or    0,0,8
+    ld    6,16(5)
+    std   0,16(4)
+    sldi   0,7, 40
+    srdi   8,6, 64-40
+    or    0,0,8
+    ld    7,24(5)
+    std   0,24(4)
+    addi  5,5,32
+    addi  4,4,32
+    bdnz+ L(du5_loop)
+    .align 4
+L(du5_fini):
+    /* calculate and store the final DW */
+    sldi   0,6, 40
+    srdi   8,7, 64-40
+    or    0,0,8  
+    std   0,0(4)
+    b     L(du_done)
+
+    .align 4
+L(du6_do):
+    bf      30,L(du6_1dw)
+
+    /* there are at least two DWs to copy */
+    sldi     0,6, 48
+    srdi     8,7, 64-48
+    or      0,0,8
+    ld      6,16(5)
+    std     0,0(4)
+    sldi     0,7, 48
+    srdi     8,6, 64-48
+    or      0,0,8
+    ld      7,24(5)
+    std     0,8(4)
+    addi    4,4,16
+    addi    5,5,32
+    blt     cr6,L(du6_fini)  /* if total DWs = 3, then bypass loop */
+    bf      31,L(du6_loop)
+    /* there is a third DW to copy */
+    sldi     0,6, 48
+    srdi     8,7, 64-48
+    or      0,0,8
+    std     0,0(4)
+    mr      6,7
+    ld      7,0(5)
+    addi    5,5,8
+    addi    4,4,8
+    beq     cr6,L(du6_fini)  /* if total DWs = 4, then bypass loop */
+    b       L(du6_loop)
+    .align 4
+L(du6_1dw):
+    sldi     0,6, 48
+    srdi     8,7, 64-48
+    addi    5,5,16
+    or      0,0,8
+    bf      31,L(du6_loop)
+    mr      6,7
+    ld      7,0(5)
+    addi    5,5,8
+    std     0,0(4)
+    addi    4,4,8
+    .align 4
+/* copy 32 bytes at a time */
+L(du6_loop):
+    sldi   0,6, 48
+    srdi   8,7, 64-48
+    or    0,0,8
+    ld    6,0(5)
+    std   0,0(4)
+    sldi   0,7, 48
+    srdi   8,6, 64-48
+    or    0,0,8
+    ld    7,8(5)
+    std   0,8(4)
+    sldi   0,6, 48
+    srdi   8,7, 64-48
+    or    0,0,8
+    ld    6,16(5)
+    std   0,16(4)
+    sldi   0,7, 48
+    srdi   8,6, 64-48
+    or    0,0,8
+    ld    7,24(5)
+    std   0,24(4)
+    addi  5,5,32
+    addi  4,4,32
+    bdnz+ L(du6_loop)
+    .align 4
+L(du6_fini):
+    /* calculate and store the final DW */
+    sldi   0,6, 48
+    srdi   8,7, 64-48
+    or    0,0,8  
+    std   0,0(4)
+    b     L(du_done)
+
+    .align 4
+L(du7_do):
+    bf      30,L(du7_1dw)
+
+    /* there are at least two DWs to copy */
+    sldi     0,6, 56
+    srdi     8,7, 64-56
+    or      0,0,8
+    ld      6,16(5)
+    std     0,0(4)
+    sldi     0,7, 56
+    srdi     8,6, 64-56
+    or      0,0,8
+    ld      7,24(5)
+    std     0,8(4)
+    addi    4,4,16
+    addi    5,5,32
+    blt     cr6,L(du7_fini)  /* if total DWs = 3, then bypass loop */
+    bf      31,L(du7_loop)
+    /* there is a third DW to copy */
+    sldi     0,6, 56
+    srdi     8,7, 64-56
+    or      0,0,8
+    std     0,0(4)
+    mr      6,7
+    ld      7,0(5)
+    addi    5,5,8
+    addi    4,4,8
+    beq     cr6,L(du7_fini)  /* if total DWs = 4, then bypass loop */
+    b       L(du7_loop)
+    .align 4
+L(du7_1dw):
+    sldi     0,6, 56
+    srdi     8,7, 64-56
+    addi    5,5,16
+    or      0,0,8
+    bf      31,L(du7_loop)
+    mr      6,7
+    ld      7,0(5)
+    addi    5,5,8
+    std     0,0(4)
+    addi    4,4,8
+    .align 4
+/* copy 32 bytes at a time */
+L(du7_loop):
+    sldi   0,6, 56
+    srdi   8,7, 64-56
+    or    0,0,8
+    ld    6,0(5)
+    std   0,0(4)
+    sldi   0,7, 56
+    srdi   8,6, 64-56
+    or    0,0,8
+    ld    7,8(5)
+    std   0,8(4)
+    sldi   0,6, 56
+    srdi   8,7, 64-56
+    or    0,0,8
+    ld    6,16(5)
+    std   0,16(4)
+    sldi   0,7, 56
+    srdi   8,6, 64-56
+    or    0,0,8
+    ld    7,24(5)
+    std   0,24(4)
+    addi  5,5,32
+    addi  4,4,32
+    bdnz+ L(du7_loop)
+    .align 4
+L(du7_fini):
+    /* calculate and store the final DW */
+    sldi   0,6, 56
+    srdi   8,7, 64-56
+    or    0,0,8  
+    std   0,0(4)
+    b     L(du_done)
+    
+    .align 4
+L(du_done):
+    rldicr 0,31,0,60
+    mtcrf 0x01,31
+    beq   cr1,0f	/* If the tail is 0 bytes we are done!  */
+
+    add   3,3,0
+    add   12,12,0    
+/*  At this point we have a tail of 0-7 bytes and we know that the
+    destiniation is double word aligned.  */
+4:  bf    29,2f
+    lwz   6,0(12)
+    addi  12,12,4
+    stw   6,0(3)
+    addi  3,3,4
+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)
+    stb   6,0(3)
+0:
+  /* Return original dst pointer.  */
+    ld 31,-8(1)
+    ld 3,-16(1)
+    blr
+END_GEN_TB (BP_SYM (memcpy),TB_TOCLESS)
+libc_hidden_builtin_def (memcpy)