/* * 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 * assembler 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> /* Experimentally off - libc_hidden_proto(memset) */ static __inline__ int expand_byte_word(int c){ /* this does: c = c << 8 | c; c = c << 16 | c ; */ __asm__("rlwimi %0,%0,8,16,23\n" "\trlwimi %0,%0,16,0,15\n" : "=r" (c) : "0" (c)); return c; } void *memset(void *to, int c, size_t n) { unsigned long rem, chunks; unsigned char *tmp_to; chunks = n / 8; tmp_to = to - 4; c = expand_byte_word(c); if (!chunks) goto lessthan8; rem = (unsigned long )tmp_to % 4; if (rem) goto align; copy_chunks: do { *(unsigned long *)(tmp_to+4) = c; tmp_to += 4; *(unsigned long *)(tmp_to+4) = c; tmp_to += 4; } while (--chunks); lessthan8: n = n % 8; if (n >= 4) { *(unsigned long *)(tmp_to+4) = c; tmp_to += 4; n = n-4; } if (!n ) return to; tmp_to += 3; do { *++tmp_to = c; } while (--n); return to; align: rem = 4 - rem; n = n-rem; do { *(tmp_to+4) = c; ++tmp_to; } while (--rem); chunks = n / 8; if (chunks) goto copy_chunks; goto lessthan8; } libc_hidden_def(memset)