+ union ieee754_double temp;
+
+ /* Compute next state. */
+ if (_drand48_iterate(xsubi, buffer) < 0)
+ return -1;
+
+ /* Construct a positive double with the 48 random bits distributed over
+ its fractional part so the resulting FP number is [0.0,1.0). */
+
+ temp.ieee.negative = 0;
+ temp.ieee.exponent = IEEE754_DOUBLE_BIAS;
+ temp.ieee.mantissa0 = (xsubi[2] << 4) | (xsubi[1] >> 12);
+ temp.ieee.mantissa1 = ((xsubi[1] & 0xfff) << 20) | (xsubi[0] << 4);
+
+ /* Please note the lower 4 bits of mantissa1 are always 0. */
+ *result = temp.d - 1.0;
+
+ return 0;
+}
+
+int _drand48_iterate(unsigned short int xsubi[3],
+ struct drand48_data *buffer)
+{
+ uint64_t X;
+ uint64_t result;
+
+ /* Initialize buffer, if not yet done. */
+
+ if (buffer->__init == 0) {
+ buffer->__a = 0x5deece66dull;
+ buffer->__c = 0xb;
+ buffer->__init = 1;
+ }
+
+ /* Do the real work. We choose a data type which contains at least
+ 48 bits. Because we compute the modulus it does not care how
+ many bits really are computed. */
+
+ X = (uint64_t) xsubi[2] << 32 | (uint32_t) xsubi[1] << 16 | xsubi[0];
+
+ result = X * buffer->__a + buffer->__c;
+
+
+ xsubi[0] = result & 0xffff;
+ xsubi[1] = (result >> 16) & 0xffff;
+ xsubi[2] = (result >> 32) & 0xffff;
+
+ return 0;
+}
+
+
+double _drand48(void)
+{
+ double result;
+
+ (void) _erand48_r(__libc_drand48_data.__x, &__libc_drand48_data,
+ &result);
+
+ return result;