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| /*
| * This provides an optimized implementation of memcpy, and a simplified
| * implementation of memset and memmove. These are used here because the
| * standard kernel runtime versions are not yet available and we don't
| * trust the gcc built-in implementations as they may do unexpected things
| * (e.g. FPU ops) in the minimal decompression stub execution environment.
| */
| #include "error.h"
|
| #include "../string.c"
|
| #ifdef CONFIG_X86_32
| static void *__memcpy(void *dest, const void *src, size_t n)
| {
| int d0, d1, d2;
| asm volatile(
| "rep ; movsl\n\t"
| "movl %4,%%ecx\n\t"
| "rep ; movsb\n\t"
| : "=&c" (d0), "=&D" (d1), "=&S" (d2)
| : "0" (n >> 2), "g" (n & 3), "1" (dest), "2" (src)
| : "memory");
|
| return dest;
| }
| #else
| static void *__memcpy(void *dest, const void *src, size_t n)
| {
| long d0, d1, d2;
| asm volatile(
| "rep ; movsq\n\t"
| "movq %4,%%rcx\n\t"
| "rep ; movsb\n\t"
| : "=&c" (d0), "=&D" (d1), "=&S" (d2)
| : "0" (n >> 3), "g" (n & 7), "1" (dest), "2" (src)
| : "memory");
|
| return dest;
| }
| #endif
|
| void *memset(void *s, int c, size_t n)
| {
| int i;
| char *ss = s;
|
| for (i = 0; i < n; i++)
| ss[i] = c;
| return s;
| }
|
| void *memmove(void *dest, const void *src, size_t n)
| {
| unsigned char *d = dest;
| const unsigned char *s = src;
|
| if (d <= s || d - s >= n)
| return __memcpy(dest, src, n);
|
| while (n-- > 0)
| d[n] = s[n];
|
| return dest;
| }
|
| /* Detect and warn about potential overlaps, but handle them with memmove. */
| void *memcpy(void *dest, const void *src, size_t n)
| {
| if (dest > src && dest - src < n) {
| warn("Avoiding potentially unsafe overlapping memcpy()!");
| return memmove(dest, src, n);
| }
| return __memcpy(dest, src, n);
| }
|
|
