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Diffstat (limited to 'src/lib/common/memcpy.c')
| -rw-r--r-- | src/lib/common/memcpy.c | 102 |
1 files changed, 102 insertions, 0 deletions
diff --git a/src/lib/common/memcpy.c b/src/lib/common/memcpy.c new file mode 100644 index 0000000..77827dc --- /dev/null +++ b/src/lib/common/memcpy.c @@ -0,0 +1,102 @@ +/* IBM_PROLOG_BEGIN_TAG */ +/* This is an automatically generated prolog. */ +/* */ +/* $Source: src/lib/common/memcpy.c $ */ +/* */ +/* OpenPOWER OnChipController Project */ +/* */ +/* Contributors Listed Below - COPYRIGHT 2015 */ +/* [+] International Business Machines Corp. */ +/* */ +/* */ +/* Licensed under the Apache License, Version 2.0 (the "License"); */ +/* you may not use this file except in compliance with the License. */ +/* You may obtain a copy of the License at */ +/* */ +/* http://www.apache.org/licenses/LICENSE-2.0 */ +/* */ +/* Unless required by applicable law or agreed to in writing, software */ +/* distributed under the License is distributed on an "AS IS" BASIS, */ +/* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or */ +/* implied. See the License for the specific language governing */ +/* permissions and limitations under the License. */ +/* */ +/* IBM_PROLOG_END_TAG */ +// $Id: memcpy.c,v 1.1.1.1 2013/12/11 20:49:20 bcbrock Exp $ +// $Source: /afs/awd/projects/eclipz/KnowledgeBase/.cvsroot/eclipz/chips/p8/working/procedures/lib/memcpy.c,v $ +//----------------------------------------------------------------------------- +// *! (C) Copyright International Business Machines Corp. 2013 +// *! All Rights Reserved -- Property of IBM +// *! *** IBM Confidential *** +//----------------------------------------------------------------------------- + +/// \file memcpy.c +/// \brief The memcpy() function + +#include "kernel.h" + +/// The memcpy() function copies \a n bytes from memory area \a src to memory +/// area \a dest. The memory areas should not overlap. Use memmove(3) if the +/// memory areas do overlap. The memcpy() function returns a pointer to dest. + +// This implementation should work well for both 32-bit and 64-bit machines, +// assuming they can handle unaligned accesses. The implementation assumes that +// it is better to avoid the loop setup overhead by a test and branch for +// cases where loops can be bypassed. + +//void * +//memcpy(void *dest, const void *src, size_t n) +//{ +// while(n--) { +// *dest++ = *src++; +// } +// +// return s; +//} + +void * +memcpy(void *dest, const void *src, size_t n) +{ + uint8_t *d8, *s8; + uint64_t *d64, *s64; + size_t doublewords, octawords; + + // First copy memory 32 bytes at a time. + + d64 = (uint64_t *)dest; + s64 = (uint64_t *)src; + octawords = n / 32; + if (octawords) { + n -= octawords * 32; + while(octawords--) { + *d64++ = *s64++; + *d64++ = *s64++; + *d64++ = *s64++; + *d64++ = *s64++; + } + } + + // Now set memory 8 bytes at a time. This might actually be better done + // explicitly rather than as a loop because the maximum loop count is 3 + // here. + + doublewords = n / 8; + if (doublewords) { + n -= doublewords * 8; + while (doublewords--) { + *d64++ = *s64++; + } + } + + // Finally finish any remaining memory bytewise + + if (n) { + d8 = (uint8_t *)d64; + s8 = (uint8_t *)s64; + while (n--) { + *d8++ = *s8++; + } + } + + return dest; +} |
