1// Copyright 2016 The Fuchsia Authors 2// Copyright (c) 2008 Travis Geiselbrecht 3// 4// Use of this source code is governed by a MIT-style 5// license that can be found in the LICENSE file or at 6// https://opensource.org/licenses/MIT 7 8#include <string.h> 9#include <sys/types.h> 10 11#if !_ASM_MEMMOVE 12 13typedef long word; 14 15#define lsize sizeof(word) 16#define lmask (lsize - 1) 17 18void * 19memmove(void *dest, void const *src, size_t count) 20{ 21 char *d = (char *)dest; 22 const char *s = (const char *)src; 23 int len; 24 25 if (count == 0 || dest == src) 26 return dest; 27 28 if ((long)d < (long)s) { 29 if (((long)d | (long)s) & lmask) { 30 // src and/or dest do not align on word boundary 31 if ((((long)d ^ (long)s) & lmask) || (count < lsize)) 32 len = count; // copy the rest of the buffer with the byte mover 33 else 34 len = lsize - ((long)d & lmask); // move the ptrs up to a word boundary 35 36 count -= len; 37 for (; len > 0; len--) 38 *d++ = *s++; 39 } 40 for (len = count / lsize; len > 0; len--) { 41 *(word *)d = *(word *)s; 42 d += lsize; 43 s += lsize; 44 } 45 for (len = count & lmask; len > 0; len--) 46 *d++ = *s++; 47 } else { 48 d += count; 49 s += count; 50 if (((long)d | (long)s) & lmask) { 51 // src and/or dest do not align on word boundary 52 if ((((long)d ^ (long)s) & lmask) || (count <= lsize)) 53 len = count; 54 else 55 len = ((long)d & lmask); 56 57 count -= len; 58 for (; len > 0; len--) 59 *--d = *--s; 60 } 61 for (len = count / lsize; len > 0; len--) { 62 d -= lsize; 63 s -= lsize; 64 *(word *)d = *(word *)s; 65 } 66 for (len = count & lmask; len > 0; len--) 67 *--d = *--s; 68 } 69 70 return dest; 71} 72 73#endif 74 75