(Comp.sys.handhelds)
Item: 2552 by cloos at acsu.buffalo.edu
Author: [James H. Cloos]
  Subj: (HP48SX) TF, a toggle flag program
  Date: Fri Mar 29 1991

Hello,

Please find eclosed a usrlang and a rpl version of TF, a program that
toggles a flag.  The syntax is the same as for SF and CF.  (There may
actually be a routine in ROM that does this, but I haven't found one yet.)

First, the usrlang version in ASCII mode:

--------------------------------------------------START_HERE-
%%HP: T(3)A(R)F(.);
\<< DUP FS?C \<< DROP \>> \<< SF \>> IFTE \>>
---------------------------------------------------END_HERE--

Here is the RPLC version of the rpl version, using a minimal symbol table:

--------------------------------------------------START_HERE-
/* tf.rplc  - by James H. Cloos, Jr. */
/* USE AT YOUR OWN RISK */
/* Note that RPLC format is free form wrt whitespace, just like C. */
// Also note that comments are as per C++.

:: ==18ECEh
    #1  :: ==3188h ==1C4BFh ==61AD8h ==3244h ==1C28Dh ;
;
---------------------------------------------------END_HERE--

(The logic is basically the same; FS?C is used in preference to FC?C as
FC?C at this level is basically a :: fs?c not ;.)

The list file from star, cut to the essential section (ie, p2) is:

STAR 1.04.4     Thu Mar 28 20:37:59 1991                        tf.star - 2

  1   70010                     
  2   70010                     ;;      RPLC version A.1.3
  3   70010                     
  4   70010  d9d20                      data.a  type_col
  5   70015  ece81                      data.a  x'18ece         ;; Switch1
  6   7001a  9ff30                      data.a  x'3ff9          ;; #1
  7   7001f  d9d20                      data.a  type_col
  8   70024  88130                      data.a  x'3188          ;; dup
  9   70029  fb4c1                      data.a  x'1c4bf         ;;
fs?c_1real
 10   7002e  8da16                      data.a  x'61ad8         ;; *see
below*
 11   70033  44230                      data.a  x'3244          ;; drop
 12   70038  d82c1                      data.a  x'1c28d         ;; sf_1real
 13   7003d  b2130                      data.a  semi
 14   70042  b2130                      data.a  semi
 15   70047                     

(The names Switch1 thru sf_real added by hand.)
Derek calls 61ad8: "if pop TOS = True, then do/skip else skip/do"

As written, if a too_few_args or _bad_arg_type error is generated, you'll
get the message "XLIB lll ccc Error:."  I left this this way as it will
eventually be part of a lib I'll be posting.  When included in a lib,
errors will show up as "TF Error:" instead.  (BTW, a quick calculation
suggests that the XLIB number in the above error message would be
"XLIB 1620 36" for the name 'TF' (it is a consequence of how lib's and
dir's are stored internally; see my previous posting on the subject).)