path: root/sysdeps/powerpc/powerpc32/a2/memcpy.S

/* Optimized memcpy implementation for PowerPC A2.
   Copyright (C) 2010-2025 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, see
   <https://www.gnu.org/licenses/>.  */

#include <sysdep.h>
#include <rtld-global-offsets.h>

#define PREFETCH_AHEAD 4        /* no cache lines SRC prefetching ahead  */
#define ZERO_AHEAD 2            /* no cache lines DST zeroing ahead  */

	.machine  a2
EALIGN (memcpy, 5, 0)
	CALL_MCOUNT

	dcbt    0,r4            /* Prefetch ONE SRC cacheline  */
	cmplwi  cr1,r5,16       /* is size < 16 ?  */
	mr      r6,r3           /* Copy dest reg to r6; */
	blt+    cr1,L(shortcopy)


	/* Big copy (16 bytes or more)

	   Figure out how far to the nearest quadword boundary, or if we are
	   on one already.

	   r3 - return value (always)
	   r4 - current source addr
	   r5 - copy length
	   r6 - current dest addr
	*/

	neg     r8,r3           /* LS 4 bits = # bytes to 8-byte dest bdry  */
	clrlwi  r8,r8,32-4      /* align to 16byte boundary  */
	sub     r7,r4,r3        /* compute offset to src from dest */
	cmplwi  cr0,r8,0        /* Were we aligned on a 16 byte bdy? */
	beq+    L(dst_aligned)



	/* Destination is not aligned on quadword boundary.  Get us to one.

	   r3 - return value (always)
	   r4 - current source addr
	   r5 - copy length
	   r6 - current dest addr
	   r7 - offset to src from dest
	   r8 - number of bytes to quadword boundary
	*/

	mtcrf   0x01,r8         /* put #bytes to boundary into cr7  */
	subf    r5,r8,r5        /* adjust remaining len */

	bf      cr7*4+3,1f
	lbzx    r0,r7,r6        /* copy 1 byte addr */
	stb     r0,0(r6)
	addi    r6,r6,1
1:
	bf      cr7*4+2,2f
	lhzx    r0,r7,r6        /*