diff options
Diffstat (limited to 'security/nss/lib/freebl/verified/karamel/include/krml/fstar_int.h')
-rw-r--r-- | security/nss/lib/freebl/verified/karamel/include/krml/fstar_int.h | 89 |
1 files changed, 89 insertions, 0 deletions
diff --git a/security/nss/lib/freebl/verified/karamel/include/krml/fstar_int.h b/security/nss/lib/freebl/verified/karamel/include/krml/fstar_int.h new file mode 100644 index 0000000000..c7a5afb50a --- /dev/null +++ b/security/nss/lib/freebl/verified/karamel/include/krml/fstar_int.h @@ -0,0 +1,89 @@ +#ifndef __FSTAR_INT_H +#define __FSTAR_INT_H + +#include "internal/types.h" + +/* + * Arithmetic Shift Right operator + * + * In all C standards, a >> b is implementation-defined when a has a signed + * type and a negative value. See e.g. 6.5.7 in + * http://www.open-std.org/jtc1/sc22/wg14/www/docs/n2310.pdf + * + * GCC, MSVC, and Clang implement a >> b as an arithmetic shift. + * + * GCC: https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Integers-implementation.html#Integers-implementation + * MSVC: https://docs.microsoft.com/en-us/cpp/cpp/left-shift-and-right-shift-operators-input-and-output?view=vs-2019#right-shifts + * Clang: tested that Clang 7, 8 and 9 compile this to an arithmetic shift + * + * We implement arithmetic shift right simply as >> in these compilers + * and bail out in others. + */ + +#if !(defined(_MSC_VER) || defined(__GNUC__) || (defined(__clang__) && (__clang_major__ >= 7))) + +static inline int8_t +FStar_Int8_shift_arithmetic_right(int8_t a, uint32_t b) +{ + do { + KRML_HOST_EPRINTF("Could not identify compiler so could not provide an implementation of signed arithmetic shift right.\n"); + KRML_HOST_EXIT(255); + } while (0); +} + +static inline int16_t +FStar_Int16_shift_arithmetic_right(int16_t a, uint32_t b) +{ + do { + KRML_HOST_EPRINTF("Could not identify compiler so could not provide an implementation of signed arithmetic shift right.\n"); + KRML_HOST_EXIT(255); + } while (0); +} + +static inline int32_t +FStar_Int32_shift_arithmetic_right(int32_t a, uint32_t b) +{ + do { + KRML_HOST_EPRINTF("Could not identify compiler so could not provide an implementation of signed arithmetic shift right.\n"); + KRML_HOST_EXIT(255); + } while (0); +} + +static inline int64_t +FStar_Int64_shift_arithmetic_right(int64_t a, uint32_t b) +{ + do { + KRML_HOST_EPRINTF("Could not identify compiler so could not provide an implementation of signed arithmetic shift right.\n"); + KRML_HOST_EXIT(255); + } while (0); +} + +#else + +static inline int8_t +FStar_Int8_shift_arithmetic_right(int8_t a, uint32_t b) +{ + return (a >> b); +} + +static inline int16_t +FStar_Int16_shift_arithmetic_right(int16_t a, uint32_t b) +{ + return (a >> b); +} + +static inline int32_t +FStar_Int32_shift_arithmetic_right(int32_t a, uint32_t b) +{ + return (a >> b); +} + +static inline int64_t +FStar_Int64_shift_arithmetic_right(int64_t a, uint32_t b) +{ + return (a >> b); +} + +#endif /* !(defined(_MSC_VER) ... ) */ + +#endif /* __FSTAR_INT_H */ |