HP 50g: Mantissa of an Extended Real

[Gerald H]

Here is my attempt at a solution, but I fear the programme is too large & slow:

Code:

::
  CK1&Dispatch
  BINT63
  ::
    DUP
    %%0=
    ?SEMI
    %%ABS
    %%10
    OVER
    DO>STR
    DUP
    CHR_E
    BINT1
    POSCHR
    #1+LAST$
    FPTR2 ^S>Z
    FPTR2 ^Z2%%
    %%^
    %%/
  ;
;