From dbcea3e4c96fcd884e9cd9ab59ac21e00c359b97 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Niels=20M=C3=B6ller?= Date: Thu, 23 Oct 2014 14:15:41 +0200 Subject: Split memxor.c into memxor.c and memxor3.c. --- memxor.c | 217 +-------------------------------------------------------------- 1 file changed, 2 insertions(+), 215 deletions(-) (limited to 'memxor.c') diff --git a/memxor.c b/memxor.c index 940da020..a252a13d 100644 --- a/memxor.c +++ b/memxor.c @@ -1,6 +1,6 @@ /* memxor.c - Copyright (C) 2010 Niels Möller + Copyright (C) 2010, 2014 Niels Möller This file is part of GNU Nettle. @@ -40,24 +40,7 @@ #include #include "memxor.h" - -/* For uintptr_t */ -#include "nettle-types.h" - -#if defined(__x86_64__) || defined(__arch64__) -/* Including on M$ windows, where unsigned long is only 32 bits */ -typedef uint64_t word_t; -#else -typedef unsigned long int word_t; -#endif - -#define ALIGN_OFFSET(p) ((uintptr_t) (p) % sizeof(word_t)) - -#ifndef WORDS_BIGENDIAN -#define MERGE(w0, sh_1, w1, sh_2) (((w0) >> (sh_1)) | ((w1) << (sh_2))) -#else -#define MERGE(w0, sh_1, w1, sh_2) (((w0) << (sh_1)) | ((w1) >> (sh_2))) -#endif +#include "memxor-internal.h" #define WORD_T_THRESH 16 @@ -159,199 +142,3 @@ memxor(void *dst_in, const void *src_in, size_t n) return dst; } - - -/* XOR word-aligned areas. n is the number of words, not bytes. */ -static void -memxor3_common_alignment (word_t *dst, - const word_t *a, const word_t *b, size_t n) -{ - /* FIXME: Require n > 0? */ - if (n & 1) - { - n--; - dst[n] = a[n] ^ b[n]; - } - while (n > 0) - { - n -= 2; - dst[n+1] = a[n+1] ^ b[n+1]; - dst[n] = a[n] ^ b[n]; - } -} - -static void -memxor3_different_alignment_b (word_t *dst, - const word_t *a, const char *b, unsigned offset, size_t n) -{ - int shl, shr; - const word_t *b_word; - - word_t s0, s1; - - shl = CHAR_BIT * offset; - shr = CHAR_BIT * (sizeof(word_t) - offset); - - b_word = (const word_t *) ((uintptr_t) b & -sizeof(word_t)); - - if (n & 1) - { - n--; - s1 = b_word[n]; - s0 = b_word[n+1]; - dst[n] = a[n] ^ MERGE (s1, shl, s0, shr); - } - else - s1 = b_word[n]; - - while (n > 0) - { - n -= 2; - s0 = b_word[n+1]; - dst[n+1] = a[n+1] ^ MERGE(s0, shl, s1, shr); - s1 = b_word[n]; - dst[n] = a[n] ^ MERGE(s1, shl, s0, shr); - } -} - -static void -memxor3_different_alignment_ab (word_t *dst, - const char *a, const char *b, - unsigned offset, size_t n) -{ - int shl, shr; - const word_t *a_word; - const word_t *b_word; - - word_t s0, s1; - - shl = CHAR_BIT * offset; - shr = CHAR_BIT * (sizeof(word_t) - offset); - - a_word = (const word_t *) ((uintptr_t) a & -sizeof(word_t)); - b_word = (const word_t *) ((uintptr_t) b & -sizeof(word_t)); - - if (n & 1) - { - n--; - s1 = a_word[n] ^ b_word[n]; - s0 = a_word[n+1] ^ b_word[n+1]; - dst[n] = MERGE (s1, shl, s0, shr); - } - else - s1 = a_word[n] ^ b_word[n]; - - while (n > 0) - { - n -= 2; - s0 = a_word[n+1] ^ b_word[n+1]; - dst[n+1] = MERGE(s0, shl, s1, shr); - s1 = a_word[n] ^ b_word[n]; - dst[n] = MERGE(s1, shl, s0, shr); - } -} - -static void -memxor3_different_alignment_all (word_t *dst, - const char *a, const char *b, - unsigned a_offset, unsigned b_offset, - size_t n) -{ - int al, ar, bl, br; - const word_t *a_word; - const word_t *b_word; - - word_t a0, a1, b0, b1; - - al = CHAR_BIT * a_offset; - ar = CHAR_BIT * (sizeof(word_t) - a_offset); - bl = CHAR_BIT * b_offset; - br = CHAR_BIT * (sizeof(word_t) - b_offset); - - a_word = (const word_t *) ((uintptr_t) a & -sizeof(word_t)); - b_word = (const word_t *) ((uintptr_t) b & -sizeof(word_t)); - - if (n & 1) - { - n--; - a1 = a_word[n]; a0 = a_word[n+1]; - b1 = b_word[n]; b0 = b_word[n+1]; - - dst[n] = MERGE (a1, al, a0, ar) ^ MERGE (b1, bl, b0, br); - } - else - { - a1 = a_word[n]; - b1 = b_word[n]; - } - - while (n > 0) - { - n -= 2; - a0 = a_word[n+1]; b0 = b_word[n+1]; - dst[n+1] = MERGE(a0, al, a1, ar) ^ MERGE(b0, bl, b1, br); - a1 = a_word[n]; b1 = b_word[n]; - dst[n] = MERGE(a1, al, a0, ar) ^ MERGE(b1, bl, b0, br); - } -} - -/* Current implementation processes data in descending order, to - support overlapping operation with one of the sources overlapping - the start of the destination area. This feature is used only - internally by cbc decrypt, and it is not advertised or documented - to nettle users. */ -void * -memxor3(void *dst_in, const void *a_in, const void *b_in, size_t n) -{ - char *dst = dst_in; - const char *a = a_in; - const char *b = b_in; - - if (n >= WORD_T_THRESH) - { - unsigned i; - unsigned a_offset; - unsigned b_offset; - size_t nwords; - - for (i = ALIGN_OFFSET(dst + n); i > 0; i--) - { - n--; - dst[n] = a[n] ^ b[n]; - } - - a_offset = ALIGN_OFFSET(a + n); - b_offset = ALIGN_OFFSET(b + n); - - nwords = n / sizeof (word_t); - n %= sizeof (word_t); - - if (a_offset == b_offset) - { - if (!a_offset) - memxor3_common_alignment((word_t *) (dst + n), - (const word_t *) (a + n), - (const word_t *) (b + n), nwords); - else - memxor3_different_alignment_ab((word_t *) (dst + n), - a + n, b + n, a_offset, - nwords); - } - else if (!a_offset) - memxor3_different_alignment_b((word_t *) (dst + n), - (const word_t *) (a + n), b + n, - b_offset, nwords); - else if (!b_offset) - memxor3_different_alignment_b((word_t *) (dst + n), - (const word_t *) (b + n), a + n, - a_offset, nwords); - else - memxor3_different_alignment_all((word_t *) (dst + n), a + n, b + n, - a_offset, b_offset, nwords); - - } - while (n-- > 0) - dst[n] = a[n] ^ b[n]; - - return dst; -} -- cgit v1.2.1