/* stropt/memcpy_440.S, pl_string_common, pl_linux 10/11/04 11:45:36
* ==========================================================================
* Optimized memcpy implementation for IBM PowerPC 440.
*
* Copyright (c) 2003, IBM Corporation
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or
* without modification, are permitted provided that the following
* conditions are met:
*
* * Redistributions of source code must retain the above
* copyright notice, this list of conditions and the following
* disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials
* provided with the distribution.
* * Neither the name of IBM nor the names of its contributors
* may be used to endorse or promote products derived from this
* software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
* CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
* OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
* USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* ==========================================================================
*
* Function: Copy n bytes of the source to the destination. Behavior is
* undefined for objects that overlap.
*
*
* void *memcpy(void * dest, const void * src, int n)
*
* Input: r3 - destination address
* r4 - source address
* r5 - byte count
* Output: r3 - destination address
*
* ==========================================================================
*/
#if defined(_KERNEL) && defined(PPC_OEA601)
/*
* 601 will generate alignment exceptions if operand crosses
* 4k page boundary, so do byte copy when exception handler
* not available. Maybe want to have a different memcpy for 601
* that checks for page boundaries/word alignment...
*/
mfspr %r6, 287 /* mfpvbr %r6 PVR = 287 */
srwi %r6, %r6, 0x10 /* get version field from PVR */
cmpwi %r6, 0x1 /* 601 CPU = 0x0001 */
bne bnorm /* skip byte-only unless 601 */
or %r6, %r3, %r4 /* see if both source and dest */
andi. %r6, %r6, 3 /* are 32bit aligned */
beq bnorm /* skip byte-only if they are */
bcpy:
mtctr %r5 /* byte copy everything */
li %r6, 0
bloop:
lbzx %r7, %r4, %r6
stbx %r7, %r3, %r6
addi %r6, %r6, 1
bdnz bloop
blr
bnorm:
#endif
mr %r8, %r3 /* Copy dst (return value) */
addi %r4, %r4, -4 /* Prepare for main loop's auto */
addi %r8, %r8, -4 /* update */
srwi. %r9,%r5,2 /* Word count -> r9 */
beq- last1 /* Partial copy if <4 bytes */
mtctr %r9 /* Word cnt in CTR for loop */
lwzu %r7, 4(%r4) /* Preload for main loop */
b g1
g0: /* Main loop */
lwzu %r7, 4(%r4) /* Load a new word */
stwu %r6, 4(%r8) /* Store previous word */
g1:
bdz- last /* Dec ctr and exit loop if no */
/* more words */
lwzu %r6, 4(%r4) /* Load another word */
stwu %r7, 4(%r8) /* Store previous word */
bdnz+ g0 /* Dec ctr and continue loop if */
/* more words */
mr %r7, %r6
last:
stwu %r7, 4(%r8) /* Store last word */
last1: /* Byte-by-byte copy */
clrlwi. %r5,%r5,30
beqlr
mtctr %r5
lbzu %r6, 4(%r4) /* 1st byte: update by word */
stbu %r6, 4(%r8)
bdzlr-
