Add a non-NEON variant of mbedtls_xor
Signed-off-by: Dave Rodgman <dave.rodgman@arm.com>
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@ -154,6 +154,42 @@ inline void mbedtls_xor(unsigned char *r, const unsigned char *a, const unsigned
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}
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}
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/**
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* Perform a fast block XOR operation, such that
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* r[i] = a[i] ^ b[i] where 0 <= i < n
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*
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* In some situations, this can perform better than mbedtls_xor (e.g., it's about 5%
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* better in AES-CBC).
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*
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* \param r Pointer to result (buffer of at least \p n bytes). \p r
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* may be equal to either \p a or \p b, but behaviour when
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* it overlaps in other ways is undefined.
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* \param a Pointer to input (buffer of at least \p n bytes)
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* \param b Pointer to input (buffer of at least \p n bytes)
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* \param n Number of bytes to process.
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*/
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static inline void mbedtls_xor_no_simd(unsigned char *r, const unsigned char *a, const unsigned char *b, size_t n)
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{
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size_t i = 0;
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#if defined(MBEDTLS_EFFICIENT_UNALIGNED_ACCESS)
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#if defined(__amd64__) || defined(__x86_64__) || defined(__aarch64__)
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/* This codepath probably only makes sense on architectures with 64-bit registers */
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for (; (i + 8) <= n; i += 8) {
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uint64_t x = mbedtls_get_unaligned_uint64(a + i) ^ mbedtls_get_unaligned_uint64(b + i);
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mbedtls_put_unaligned_uint64(r + i, x);
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}
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#else
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for (; (i + 4) <= n; i += 4) {
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uint32_t x = mbedtls_get_unaligned_uint32(a + i) ^ mbedtls_get_unaligned_uint32(b + i);
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mbedtls_put_unaligned_uint32(r + i, x);
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}
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#endif
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#endif
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for (; i < n; i++) {
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r[i] = a[i] ^ b[i];
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}
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}
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/* Fix MSVC C99 compatible issue
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* MSVC support __func__ from visual studio 2015( 1900 )
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* Use MSVC predefine macro to avoid name check fail.
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