quad_arg
    A 64-bit quantity, either in a register or in an aligned quadword
    memory location.
 leq_32bits
    Label to branch to if quad_arg is a 32-bit sign-extended value.
 gtr_32bits
    Label to branch to if quad_arg is greater than 32 bits.
 temp_reg=22
    Register to use as a temporary register for holding the low
    longword of the source value-R22 is the default.