From cec07c0b6129757337282287870da2d4c3958f48 Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Fri, 6 Nov 2020 17:42:36 -0800 Subject: [PATCH] qemu/host-utils: Add wrappers for overflow builtins MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit These builtins came in with gcc 5 and clang 3.8, which are slightly newer than our supported minimum compiler versions. Reviewed-by: Alex Bennée Signed-off-by: Richard Henderson --- include/qemu/host-utils.h | 225 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 225 insertions(+) diff --git a/include/qemu/host-utils.h b/include/qemu/host-utils.h index f1e52851e0..cb95626c7d 100644 --- a/include/qemu/host-utils.h +++ b/include/qemu/host-utils.h @@ -356,6 +356,231 @@ static inline uint64_t revbit64(uint64_t x) #endif } +/** + * sadd32_overflow - addition with overflow indication + * @x, @y: addends + * @ret: Output for sum + * + * Computes *@ret = @x + @y, and returns true if and only if that + * value has been truncated. + */ +static inline bool sadd32_overflow(int32_t x, int32_t y, int32_t *ret) +{ +#if __has_builtin(__builtin_add_overflow) || __GNUC__ >= 5 + return __builtin_add_overflow(x, y, ret); +#else + *ret = x + y; + return ((*ret ^ x) & ~(x ^ y)) < 0; +#endif +} + +/** + * sadd64_overflow - addition with overflow indication + * @x, @y: addends + * @ret: Output for sum + * + * Computes *@ret = @x + @y, and returns true if and only if that + * value has been truncated. + */ +static inline bool sadd64_overflow(int64_t x, int64_t y, int64_t *ret) +{ +#if __has_builtin(__builtin_add_overflow) || __GNUC__ >= 5 + return __builtin_add_overflow(x, y, ret); +#else + *ret = x + y; + return ((*ret ^ x) & ~(x ^ y)) < 0; +#endif +} + +/** + * uadd32_overflow - addition with overflow indication + * @x, @y: addends + * @ret: Output for sum + * + * Computes *@ret = @x + @y, and returns true if and only if that + * value has been truncated. + */ +static inline bool uadd32_overflow(uint32_t x, uint32_t y, uint32_t *ret) +{ +#if __has_builtin(__builtin_add_overflow) || __GNUC__ >= 5 + return __builtin_add_overflow(x, y, ret); +#else + *ret = x + y; + return *ret < x; +#endif +} + +/** + * uadd64_overflow - addition with overflow indication + * @x, @y: addends + * @ret: Output for sum + * + * Computes *@ret = @x + @y, and returns true if and only if that + * value has been truncated. + */ +static inline bool uadd64_overflow(uint64_t x, uint64_t y, uint64_t *ret) +{ +#if __has_builtin(__builtin_add_overflow) || __GNUC__ >= 5 + return __builtin_add_overflow(x, y, ret); +#else + *ret = x + y; + return *ret < x; +#endif +} + +/** + * ssub32_overflow - subtraction with overflow indication + * @x: Minuend + * @y: Subtrahend + * @ret: Output for difference + * + * Computes *@ret = @x - @y, and returns true if and only if that + * value has been truncated. + */ +static inline bool ssub32_overflow(int32_t x, int32_t y, int32_t *ret) +{ +#if __has_builtin(__builtin_sub_overflow) || __GNUC__ >= 5 + return __builtin_sub_overflow(x, y, ret); +#else + *ret = x - y; + return ((*ret ^ x) & (x ^ y)) < 0; +#endif +} + +/** + * ssub64_overflow - subtraction with overflow indication + * @x: Minuend + * @y: Subtrahend + * @ret: Output for sum + * + * Computes *@ret = @x - @y, and returns true if and only if that + * value has been truncated. + */ +static inline bool ssub64_overflow(int64_t x, int64_t y, int64_t *ret) +{ +#if __has_builtin(__builtin_sub_overflow) || __GNUC__ >= 5 + return __builtin_sub_overflow(x, y, ret); +#else + *ret = x - y; + return ((*ret ^ x) & (x ^ y)) < 0; +#endif +} + +/** + * usub32_overflow - subtraction with overflow indication + * @x: Minuend + * @y: Subtrahend + * @ret: Output for sum + * + * Computes *@ret = @x - @y, and returns true if and only if that + * value has been truncated. + */ +static inline bool usub32_overflow(uint32_t x, uint32_t y, uint32_t *ret) +{ +#if __has_builtin(__builtin_sub_overflow) || __GNUC__ >= 5 + return __builtin_sub_overflow(x, y, ret); +#else + *ret = x - y; + return x < y; +#endif +} + +/** + * usub64_overflow - subtraction with overflow indication + * @x: Minuend + * @y: Subtrahend + * @ret: Output for sum + * + * Computes *@ret = @x - @y, and returns true if and only if that + * value has been truncated. + */ +static inline bool usub64_overflow(uint64_t x, uint64_t y, uint64_t *ret) +{ +#if __has_builtin(__builtin_sub_overflow) || __GNUC__ >= 5 + return __builtin_sub_overflow(x, y, ret); +#else + *ret = x - y; + return x < y; +#endif +} + +/** + * smul32_overflow - multiplication with overflow indication + * @x, @y: Input multipliers + * @ret: Output for product + * + * Computes *@ret = @x * @y, and returns true if and only if that + * value has been truncated. + */ +static inline bool smul32_overflow(int32_t x, int32_t y, int32_t *ret) +{ +#if __has_builtin(__builtin_mul_overflow) || __GNUC__ >= 5 + return __builtin_mul_overflow(x, y, ret); +#else + int64_t z = (int64_t)x * y; + *ret = z; + return *ret != z; +#endif +} + +/** + * smul64_overflow - multiplication with overflow indication + * @x, @y: Input multipliers + * @ret: Output for product + * + * Computes *@ret = @x * @y, and returns true if and only if that + * value has been truncated. + */ +static inline bool smul64_overflow(int64_t x, int64_t y, int64_t *ret) +{ +#if __has_builtin(__builtin_mul_overflow) || __GNUC__ >= 5 + return __builtin_mul_overflow(x, y, ret); +#else + uint64_t hi, lo; + muls64(&lo, &hi, x, y); + *ret = lo; + return hi != ((int64_t)lo >> 63); +#endif +} + +/** + * umul32_overflow - multiplication with overflow indication + * @x, @y: Input multipliers + * @ret: Output for product + * + * Computes *@ret = @x * @y, and returns true if and only if that + * value has been truncated. + */ +static inline bool umul32_overflow(uint32_t x, uint32_t y, uint32_t *ret) +{ +#if __has_builtin(__builtin_mul_overflow) || __GNUC__ >= 5 + return __builtin_mul_overflow(x, y, ret); +#else + uint64_t z = (uint64_t)x * y; + *ret = z; + return z > UINT32_MAX; +#endif +} + +/** + * umul64_overflow - multiplication with overflow indication + * @x, @y: Input multipliers + * @ret: Output for product + * + * Computes *@ret = @x * @y, and returns true if and only if that + * value has been truncated. + */ +static inline bool umul64_overflow(uint64_t x, uint64_t y, uint64_t *ret) +{ +#if __has_builtin(__builtin_mul_overflow) || __GNUC__ >= 5 + return __builtin_mul_overflow(x, y, ret); +#else + uint64_t hi; + mulu64(ret, &hi, x, y); + return hi != 0; +#endif +} + /* Host type specific sizes of these routines. */ #if ULONG_MAX == UINT32_MAX -- 2.11.0