_INLINE_ uint32_t secure_l32_mask()

in include/internal/utilities.h [110:139]

• 25 lines of code
• 2 McCabe index (conditional complexity)

_INLINE_ uint32_t secure_l32_mask(IN const uint32_t v1, IN const uint32_t v2)
{
#if defined(__aarch64__)
  uint32_t res;
  __asm__ __volatile__("cmp  %w[V2], %w[V1]; \n "
                       "cset %w[RES], HI; \n"
                       : [RES] "=r"(res)
                       : [V1] "r"(v1), [V2] "r"(v2)
                       : "cc" /*The condition code flag*/);
  return (res - 1);
#elif defined(__x86_64__) || defined(__i386__)
  uint32_t res;
  __asm__ __volatile__("xor  %%edx, %%edx; \n"
                       "cmp  %1, %2; \n "
                       "setl %%dl; \n"
                       "dec %%edx; \n"
                       "mov %%edx, %0; \n"

                       : "=r"(res)
                       : "r"(v2), "r"(v1)
                       : "rdx");

  return res;
#else
  // If v1 >= v2 then the subtraction result is 0^32||(v1-v2).
  // else it is 1^32||(v2-v1+1). Subsequently, negating the upper
  // 32 bits gives 0 if v1 < v2 and otherwise (-1).
  return ~((uint32_t)(((uint64_t)v1 - (uint64_t)v2) >> 32));
#endif
}