/* APPLE LOCAL file 5316398 improved float/double -> int64 functions */ #include <stdint.h> int64_t __fixdfdi (double x) { union { double d; uint64_t u; } u = {x}; uint64_t fabsx = u.u & 0x7fffffffffffffffULL; uint32_t exp = fabsx >> 52; int64_t result = 0; /* for very large and reasonably small values, regular int converter works fine */ if (exp >= 52U + 1023U) /* if( |x| >= 0x1.0p52 || isnan( x ) ) */ { /* early out for error cases |x| >= 0x1.0p63 || isnan(x) */ if (exp >= 1023U + 63U) { /* special case for x == -0x1.0p63 */ if (-0x1.0p63 == x) return 0x8000000000000000ULL; /* huge, Inf, NaN */ result = (int32_t) x; /* grab sign bit */ result >>= 63; /* splat it across value */ /* return either 0x8000000000000000 or 0x7fffffffffffffff according to sign bit */ result ^= 0x7fffffffffffffffULL; return result; } /* 0x1.0p52 <= |x| < 0x1.0p63 always integer, but too big. Chop off some of the top. */ u.u &= 0xFFFFFFFF00000000ULL; /* truncate off some low bits */ x -= u.d; /* get remainder */ /* accumulate the high part into result */ int32_t hi = u.d * 0x1.0p-32; result += (int64_t) hi << 32; } else { /* |x| < 0x1.0p52 */ /* early out for |x| < 0x1.0p31 -- use hardware 32-bit conversion */ if (exp < 1023U + 31U) return (int64_t) ((int32_t) x); /* The integer result fits in the significand, but there may be some fractional bits. Value is too large to use 32-bit hardware. create a mask that covers the high 32-bit part of the number and the whole integer part. */ uint64_t intMask = (int64_t) 0xFFF0000000000000LL >> (exp - 1023); /* extract the full integer (round to integer in round to zero rounding mode) */ u.u &= intMask; /* find the fractional part */ double fraction = x - u.d; /* save the integer part */ x = u.d; /* set inexact as needed */ result = (int32_t) fraction; /* always 0 */ } /* xi is < 2**53 now and integer. Convert to integer representation. */ if (x < 0.0) { u.d = x - 0x1.0p52; result -= u.u & 0x000FFFFFFFFFFFFFULL; } else { u.d = x + 0x1.0p52; result += u.u & 0x000FFFFFFFFFFFFFULL; } return result; }