mbedtls/library/common.h

8  *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
92 /* A compile-time constant with the value 0. If `const_expr` is not a
93  * compile-time constant with a nonzero value, cause a compile-time error. */
95     (0 && sizeof(struct { unsigned int STATIC_ASSERT : 1 - 2 * !(const_expr); }))
97 /* Return the scalar value `value` (possibly promoted). This is a compile-time
98  * constant if `value` is. `condition` must be a compile-time constant.
99  * If `condition` is false, arrange to cause a compile-time error. */
108 /* If we aren't sure the compiler supports our non-standard tricks,
126  *              Guaranteed to be a no-op if \p buf is \c NULL and \p len is 0.
154 /** Return an offset into a read-only buffer.
178  * Perform a fast block XOR operation, such that
190  *            If the result is used immediately after the xor operation in non-SIMD code (e.g, in
191  *            AES-CBC), there may be additional latency to transfer the data from SIMD to scalar
193  *            the result is not used immediately (e.g., in AES-CTR), mbedtls_xor() may be faster.
213     /* This if statement helps some compilers (e.g., IAR) optimise out the byte-by-byte tail case  in mbedtls_xor()
215      * For other compilers (e.g. recent gcc and clang) it makes no difference if n is a compile-time  in mbedtls_xor()
216      * constant, and is a very small perf regression if n is not a compile-time constant.  in mbedtls_xor()
224     /* This codepath probably only makes sense on architectures with 64-bit registers */  in mbedtls_xor()
252  * inlined (e.g., observed about 3x perf difference in gcm_mult_largetable with gcc 7 - 12) */
259  * Perform a fast block XOR operation, such that
263  * better in AES-CBC).
274  *            If the result is used immediately after the xor operation in non-SIMD code (e.g, in
275  *            AES-CBC), there may be additional latency to transfer the data from SIMD to scalar
277  *            the result is not used immediately (e.g., in AES-CTR), mbedtls_xor() may be faster.
288     /* This codepath probably only makes sense on architectures with 64-bit registers */  in mbedtls_xor_no_simd()
294     /* This if statement helps some compilers (e.g., IAR) optimise out the byte-by-byte tail case  in mbedtls_xor_no_simd()
296      * For other compilers (e.g. recent gcc and clang) it makes no difference if n is a compile-time  in mbedtls_xor_no_simd()
297      * constant, and is a very small perf regression if n is not a compile-time constant. */  in mbedtls_xor_no_simd()
321  *      Use MSVC predefine macro to avoid name check fail.
324 #define /*no-check-names*/ __func__ __FUNCTION__
328 /* *INDENT-OFF* */
336 /* *INDENT-ON* */
339  * Define the constraint used for read-only pointer operands to aarch64 asm.
359 /* Normal case (64-bit pointers): use "r" as the constraint for pointer operands to asm */
369 /* Can't use the C11-style `defined(static_assert)` on FreeBSD, since it
370  * defines static_assert even with -std=c99, but then complains about it.
398  * which can result in smaller code-size. */
412 /* For gcc -Os, override with -O2 for a given function.
414  * This will not affect behaviour for other optimisation settings, e.g. -O0.
417 #define MBEDTLS_OPTIMIZE_FOR_PERFORMANCE __attribute__((optimize("-O2")))
432 /* IAR does support __attribute__((unused)), but only if the -e flag (extended language support)
435  * Check for version 5.2 or later - this pragma may be supported by earlier versions, but I wasn't
449 /* GCC >= 15 has a warning 'unterminated-string-initialization' which complains if you initialize