/* * Copyright (C) 2004 Joakim Tjernlund * Copyright (C) 2000-2005 Erik Andersen <andersen@uclibc.org> * * Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball. */ /* These are carefully optimized mem*() functions for PPC written in C. * Don't muck around with these function without checking the generated * assmbler code. * It is possible to optimize these significantly more by using specific * data cache instructions(mainly dcbz). However that requires knownledge * about the CPU's cache line size. * * BUG ALERT! * The cache instructions on MPC8xx CPU's are buggy(they don't update * the DAR register when causing a DTLB Miss/Error) and cannot be * used on 8xx CPU's without a kernel patch to work around this * problem. */ #include <string.h> #undef memcpy void attribute_hidden *__memcpy(void *to, const void *from, size_t n) /* PPC can do pre increment and load/store, but not post increment and load/store. Therefore use *++ptr instead of *ptr++. */ { unsigned long rem, chunks, tmp1, tmp2; unsigned char *tmp_to; unsigned char *tmp_from = (unsigned char *)from; chunks = n / 8; tmp_from -= 4; tmp_to = to - 4; if (!chunks) goto lessthan8; rem = (unsigned long )tmp_to % 4; if (rem) goto align; copy_chunks: do { /* make gcc to load all data, then store it */ tmp1 = *(unsigned long *)(tmp_from+4); tmp_from += 8; tmp2 = *(unsigned long *)tmp_from; *(unsigned long *)(tmp_to+4) = tmp1; tmp_to += 8; *(unsigned long *)tmp_to = tmp2; } while (--chunks); lessthan8: n = n % 8; if (n >= 4) { *(unsigned long *)(tmp_to+4) = *(unsigned long *)(tmp_from+4); tmp_from += 4; tmp_to += 4; n = n-4; } if (!n ) return to; tmp_from += 3; tmp_to += 3; do { *++tmp_to = *++tmp_from; } while (--n); return to; align: rem = 4 - rem; n = n - rem; do { *(tmp_to+4) = *(tmp_from+4); ++tmp_from; ++tmp_to; } while (--rem); chunks = n / 8; if (chunks) goto copy_chunks; goto lessthan8; } strong_alias(__memcpy, memcpy)