lslw IMM (4),d4 | exponent back to fourth byte
#else
lsll IMM (4),d4 | exponent back to fourth byte
#endif
bclr IMM (DBL_MANT_DIG-32-1),d0
swap d0 | and put back exponent
lslw IMM (4),d4 | exponent back to fourth byte
#else
lsll IMM (4),d4 | exponent back to fourth byte
#endif
bclr IMM (DBL_MANT_DIG-32-1),d0
swap d0 | and put back exponent