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Diffstat (limited to 'src/lib/string_utils.C')
| -rw-r--r-- | src/lib/string_utils.C | 119 |
1 files changed, 119 insertions, 0 deletions
diff --git a/src/lib/string_utils.C b/src/lib/string_utils.C new file mode 100644 index 000000000..2ef8419a9 --- /dev/null +++ b/src/lib/string_utils.C @@ -0,0 +1,119 @@ +/* IBM_PROLOG_BEGIN_TAG */ +/* This is an automatically generated prolog. */ +/* */ +/* $Source: src/lib/string_utils.C $ */ +/* */ +/* OpenPOWER HostBoot Project */ +/* */ +/* Contributors Listed Below - COPYRIGHT 2016,2017 */ +/* [+] 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 */ +#include <string.h> +#include <stdlib.h> + +extern "C" void *memset(void *vdest, int ch, size_t len) +{ + // TODO: align to an 8-byte boundary + // Loop, storing 8 bytes every 3 instructions + long *ldest = reinterpret_cast<long *>(vdest); + if (len >= sizeof(long)) + { + long lch = ch & 0xFF; + lch |= lch<<8; + lch |= lch<<16; + lch |= lch<<32; + size_t len8 = len / sizeof(long); + size_t i = len8; + do { + ldest[--i] = lch; + } while( i > 0 ); + ldest += len8; + len -= len8 * sizeof(long); + } + + // Loop, storing 1 byte every 3 instructions + char *cdest = reinterpret_cast<char *>(ldest); + while (len >= sizeof(char)) + { + *cdest++ = ch; + len -= sizeof(char); + } + + return vdest; +} + +extern "C" void *memcpy(void *vdest, const void *vsrc, size_t len) +{ + // TODO: align to an 8-byte boundary? + + // Loop, copying 8 bytes every 5 instructions (TODO: 8/4 should be possible) + long *ldest = reinterpret_cast<long *>(vdest); + const long *lsrc = reinterpret_cast<const long *>(vsrc); + + while (len >= sizeof(long)) + { + *ldest++ = *lsrc++; + len -= sizeof(long); + } + + // Loop, copying 1 byte every 4 instructions + char *cdest = reinterpret_cast<char *>(ldest); + const char *csrc = reinterpret_cast<const char *>(lsrc); + for (size_t i = 0; i < len; ++i) + { + cdest[i] = csrc[i]; + } + + return vdest; +} + +extern "C" void *memmove(void *vdest, const void *vsrc, size_t len) +{ + // Copy first-to-last + if (vdest <= vsrc) + { + return memcpy(vdest,vsrc,len); + } + + // Copy last-to-first (TO_DO: optimize) + char *dest = reinterpret_cast<char *>(vdest); + const char *src = reinterpret_cast<const char *>(vsrc); + for (size_t i = len; i > 0;) + { + --i; + dest[i] = src[i]; + } + + return vdest; +} + +extern "C" int memcmp(const void *p1, const void *p2, size_t len) +{ + const char *c1 = reinterpret_cast<const char *>(p1); + const char *c2 = reinterpret_cast<const char *>(p2); + + for (size_t i = 0; i < len; ++i) + { + long n = static_cast<long>(c1[i]) - static_cast<long>(c2[i]); + if (n != 0) + { + return n; + } + } + + return 0; +}
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