#ifndef SIMDJSON_ARM64_BITMANIPULATION_H

#define SIMDJSON_ARM64_BITMANIPULATION_H

#include "simdjson.h"

#include "arm64/intrinsics.h"

namespace simdjson {

namespace arm64 {

// We sometimes call trailing_zero on inputs that are zero,

// but the algorithms do not end up using the returned value.

// Sadly, sanitizers are not smart enough to figure it out.

NO_SANITIZE_UNDEFINED

really_inline int trailing_zeroes(uint64_t input_num) {

#ifdef SIMDJSON_REGULAR_VISUAL_STUDIO

unsigned long ret;

// Search the mask data from least significant bit (LSB)

// to the most significant bit (MSB) for a set bit (1).

_BitScanForward64(&ret, input_num);

return (int)ret;

#else // SIMDJSON_REGULAR_VISUAL_STUDIO

return __builtin_ctzll(input_num);

#endif // SIMDJSON_REGULAR_VISUAL_STUDIO

}

/* result might be undefined when input_num is zero */

really_inline uint64_t clear_lowest_bit(uint64_t input_num) {

return input_num & (input_num-1);

}

/* result might be undefined when input_num is zero */

really_inline int leading_zeroes(uint64_t input_num) {

#ifdef SIMDJSON_REGULAR_VISUAL_STUDIO

unsigned long leading_zero = 0;

// Search the mask data from most significant bit (MSB)

// to least significant bit (LSB) for a set bit (1).

if (_BitScanReverse64(&leading_zero, input_num))

return (int)(63 - leading_zero);

else

return 64;

#else

return __builtin_clzll(input_num);

#endif// SIMDJSON_REGULAR_VISUAL_STUDIO

}

/* result might be undefined when input_num is zero */

really_inline int count_ones(uint64_t input_num) {

return vaddv_u8(vcnt_u8(vcreate_u8(input_num)));

}

really_inline bool add_overflow(uint64_t value1, uint64_t value2, uint64_t *result) {

#ifdef SIMDJSON_REGULAR_VISUAL_STUDIO

*result = value1 + value2;

return *result < value1;

#else

return __builtin_uaddll_overflow(value1, value2,

(unsigned long long *)result);

#endif

}

really_inline bool mul_overflow(uint64_t value1, uint64_t value2, uint64_t *result) {

#ifdef SIMDJSON_REGULAR_VISUAL_STUDIO

*result = value1 * value2;

return !!__umulh(value1, value2);

#else

return __builtin_umulll_overflow(value1, value2, (unsigned long long *)result);

#endif

}

} // namespace arm64

} // namespace simdjson

#endif // SIMDJSON_ARM64_BITMANIPULATION_H