*****    ***         *     *   ****   *****  *****   ***
         *       *   *        **    *  *    *    *    *      *   *
         *          *         * *   *  *    *    *    *      *
         ****      *    ****  *  *  *  *    *    *    ***     ***
             *    *           *   * *  *    *    *    *          *
             *   *            *    **  *    *    *    *      *   *
         ****    *****        *     *   ****     *    ******  ***

         Volume 3 Number 6       48/39/38                June 1978

                     Newsletter of the SR-52 Users Club
                                published at
                           9459 Taylorsville Road
                              Dayton, OH 45424
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Friendly Competition
     It's a bit disappointing that none of HP's newly announced Series
E calculators is even on a par with the 67.  So there are still no HP
PPCs qualified to match the TI-58 or 59 in our on-going Friendly Compe-
tition (V2N4) with HP users.  However, continuing on with an old
counter-challenge, Hal Brown (V2N8p3 and V2N12p5) has collaborated
with another HP user in improving his matrix program (see PPC Journal
(formerly 65-Notes) V5N4P6,24) such that although manual rearrange-
ments are still required in some cases, the new version runs faster,
and can solve a system of 5 simultaneous equations as well as calculate
the determinant and inverse of a 5 X 5 matrix.  Avid SR-52 users may
find it challenging to translate the Brown/Robinson program, and see
if they can produce as good or better 52 versions.
     But until HP (or some other PPC manufacturer does catch up, 58/59
users will have to content themselves with same-machine challenges.
The calendar one (V3N5) is turning into a lively contest, and it is
now apparent that beating 2 minutes per printed month (V3N5p2) isn't
too hard to do.  Lou Cargile (625) and Fred Fitzgerald (252) are about
even with programs which print a year in ten minutes.  Lou uses indirect
subroutine calls to specific entry points in long strings of numeral
instructions to generate print-code strings in the display.  Such calls
are fast, but time is sometimes wasted getting to the next rtn after
the display has been filled, and this approach requires specialized
processing for non-31-day months.  Fred takes a related, but somewhat
different approach, using indirect subroutine calls to short sequences
of the form:  a.bc rtn, where a is the print-code for the tens place,
and bc the print-code for the units place for all the days (1-31).
     But it turns out that indirect recalls are faster than indirect
subroutine calls to even the shortest sequence:  rtn, and Maurice
Swinnen (779) was able to devise a single-month printer which executes
in 40-45 seconds using indirect recalls from a block of consecutive
registers, each containing 2 print codes for 2 of the integers 1-31.
Indidently, Maurice included a detailed algorithm along with mag cards,
and listings, greatly facilitating the job of determining how his pro-
gram works.  While close to the fastest calendar printer I've yet seen,
Maurice's program does a good deal of special-case handling, which off-
sets the speed gain of the print-code retrieval mechanization, and
leaves no room for routines to handle more than one month at a time.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
  The SR-52 Users Club is a non-profit loosely organised group of TI PPC owners/users
  who wish to get more out of their machines by exchanging ideas.  Activity centers
  on a monthly newsletter, 52-NOTES edited and published by Richard C Vanderburgh
  in Dayton, Ohio.  The SR-52 Users Club is neither sponsored nor officially sanctioned
  by Texas Instruments, Inc.  Membership is open to any interested person:  $6.00
  includes six future issues of 52-NOTES; back issues start June 1976 @ $1.00 each.
     Bill Skillman (710) worked out a simpler way to pack print buffers
for all cases from a block of consecutive registers, each containing
print-code for a single day.  His approach is the fastest yet:  7½
minutes per year.  The program which follows is a revision of Bill's,
cutting size and execution time a bit with the substitution of INV
Dszs for x-t comparisons, and a bunch of equally spaced GTOs for a
double indirect mechanization (the latter being more costly in regis-
ters, and slightly slower, even though more elegant).
                       Record banks 1-3 with turn-on partition.

TI-59/PC-100A Program:  Calendar Printer         Bill Skillman (710)/Ed

Program Listing:

000:  GTO 127 GTO 025 GTO 040 GTO 051 GTO 066 GTO 097 GTO 112 LA' Op0
025:  R*2 Op22 EE 6 INV EE Op1 + INV Dsz4 1' R*2 Op22 = Op1 INV Dsz4 1'
051:  R*2 Op22 EE 4 INV EE Op2 + INV Dsz4 1' R*2 Op22 EE 2 ± INV EE S5
077:  Int = Op2 R5 INV Int EE 10 INV EE Op3 + INV Dsz4 1' R*2 Op22
101:  EE 2 = INV EE Op3 INV Dsz4 1' R*2 Op22 EE 6 INV EE OP4 + INV Dsz4
126:  1' R*2 Op22 = INV EE OP 4 Op5 Dsz4 A' Adv CLR rtn L1' Op5 CLR
149:  Adv rtn LB R1 + 64 = S07 1 S2 R9 S3 Pgm20 SBR 086 S0 ÷ x:t 7 ± =
180:  Int X 7 + x:t = X 3 = S6 Op21 R9 S3 Pgm20 SBR 086 - R0 = S4 Op0
210:  R*7 Op4 R9 Op6 R64 Op1 R63 Op2 R63 Op3 R61 Op4 Op5 Op00 20 S2
242:  GTO*6 LA S9 S3 R/S S01 1 x:t Pgm1 SBR Write INV x=t Grad 8 Op17
265:  Adv Adv Adv rtn LC 13 - R1 = S8 B Dsz8 279 rtn LD - R9 + 1 =
293:  S77 C Op29 1 S1 Dsz77 295 Adv Adv R/S

Pre-stored Data:

30:  2 3 4 5 6 7 8 9 12 201 202 203 204 205 206 207 208 209 212 301
50   302 303 304 305 306 307 308 309 312 401 402 2135003613 1700372300
63:  37410043 3641003032 251331 211714 301335 133335 301345 25413117
71:  25412745 134122 36173337 321537 313242 161715

User Instructions:

1.  Key start year, press A.
2.  Key start month, press R/S; if wrong module, display flashes.
    For 1 Month:  Press B; for balance of year, press C; for specified
    interval, key end year, press D.

     Incidently, as some of us found from frustrating experience, ML-20
sometimes alters input month or year.  The routine which calculates the
day of the week (D or SBR 177) unfortunately used Reg 1 for temporary
storage, and when the input months are either January or February,
steps 112-115 decrement the year.
     Carl Seel (328) notes that "...the 4 year leap year rule doesn't
hold for centesimal years (1900, 2000, 2100, ...) which aren't evenly
divisible by 400."  ML-20 accounts for this, but as Charles Kluepfel
(757) notes, Lou Cargile's V3N5p3 program doesn't, since in neither
uses ML-20 to calculate the number of days in February, nor accounts
for the centesimal rule in any other way.  Charles also notes:  "As to
the far future, there is question whether 4000 AD will be leap year or
not, as further corrections may be necessary to the calendar."  Members
wishing to explore time keeping in greater detail are invited to read
"Measuring Time" by T R Parkin in Popular Computing V6N6p7.  In this
first of a 2-part article, Parkin presents recent Naval Observatory
figures defining the mean solar year as 365.2421946412 days on 1 Jan
1975 and "...slowing down by .53 seconds for each century after Jan

                              52-NOTES V3N6p2
     After printing V3N6p2, I received a calendar printing program
from Panos Galidas (207) which used Maurice's doubled print-code
method, but with a simpler way to handle all the special cases, and
which prints a year in 5½ minutes.  But as I examined Panos' approach
(via a detailed algorithm, which like Maurice's, expedited comprehen-
sion), it appeared that further speed enhancements could be made,
along with squeezing the code into 3 memory banks.  It turned out that
some of Bill Skillman's approach was applicable, and that using H5-8
in place of Op1-4 print buffer loading instructions, would speed up
the required left-right number shifting.  The program which follows
prints a year in just under 5 minutes (1978:  4 min 53 seconds), and
actually has more prestored data than is evident at first glance.
These data are listed as steps 465-719 for input convenience.  I sug-
gest first writing into program memory all listed steps:  000-326 and
465-719 with a 1 Op 17 partition; then storing the Reg 62-78 constants
with an 8 Op 17 partition, in order to avoid data shifts due to inser-
tions or deletions; record banks 1-3 with a 6 Op 17 partition.  During
program execution there is an effective 327.78 partition.  The V3N6p2
user instructions apply, except that there is no CROM module test.

TI-59/PC-100A Program:  Calendar Printer Ed,207,221,252,625,710,779

Program Listing:

000:  30 S0 Op27 GTO 115 31 S0 Nop Nop GTO 061 30 S0 Op27 GTO 061 31
029:  S0 Nop Nop GTO 078 31 S0 Nop Nop GTO 096 30 S0 Op27 GTO 096 31
056:  S0 GTO 115 R*0 INV Dsz7 139 H5 INV Dsz7 172 2 SUM0 R*0 + 99.99
086:  = INV Dsz7 145 H6 Op20 R*0 INV Int INV Dsz7 157 H7 INV Dsz7 172
112:  2 SUM0 R*0 INV Dsz7 169 H8 INV Dsz7 172 2 SUM0 Op5 Op0 GTO 061
139:  EE H5 GTO 172 + R62 - R62 = H6 GTO 172 + R62 - R62 = H7 GTO 172
169:  EE H8 Op5 Op0 Adv CLR rtn LB R1 + 66 = S01 1 S2 R9 S3 Pgm20
198:  SBR086 S0 ÷ x:t 7 ± = Int X 7 + x:t = X 9 = S6 Op21 R9 S3 Pgm20
227:  SBR086 - R0 = S7 Op00 8 Op17 R*8 Op4 R9 Op06 7 Op17 R66 Op1 R65
258:  Op2 R64 Op3 R63 Op5 Op5 Op0 GTO*6 LA S9 S3 R/S S1 rtn LC 13 -
289:  R1 = S4 SBR181 Dsz4 294 rtn LD - R9 + 1 = S5 SBR286 Op29 1 S1
320:  Dsz5 312 Adv Adv R/S

465:  0 0 0 CLR' Ind E' E' 0 CLR' Ind 0 E' Ind E' E' 0 E' Ind 0 CLR'
485:  p31 E' E' 0 CLR' p31 0 E' p31 E' E' 0 E' p31 0 0 p31 E' E' 0 0
506:  p31 0 Rad tan E' E' 0 Rad tan 0 Deg tan E' E' 0 Deg tan 0 Abs
525:  tan E' E' 0 Abs tan 0 Ind tan E' E' 0 Ind tan 0 tan tan E' E'
544:  0 tan tan 0 CLR' tan E' E' 0 CLR' tan 0 E' tan E' E' - E' tan 0
564:  CLR' p21 E' E' 0 CLR' p21 0 E' p21 E' E' 0 E' p21 0 0 p21 E' E'
584:  0 0 p21 0 Rad CLR' E' E' 0 Rad CLR' 0 Deg CLR' E' E' 0 Deg CLR'
603:  0 Abs CLR' E' E' 0 Abs CLR' 0 Ind CLR' E' E' 0 Ind CLR' 0 tan CLR'
622:  E' E' 0 tan CLR' 0 CLR' CLR' E' E' 0 CLR' CLR' 0 E' CLR' E' E'
640:  0 E' CLR' 0 CLR' 1 E' E' 0 CLR' 1 0 E' 1 E' E' 0 E' 1 0 0 1 E'
663:  E' 0 0 1 0 Rad 0 E' E' 0 Rad 0 0 Deg 0 E' E' 0 Deg 0 0 Abs 0 E'
687:  E' 0 Abs 0 0 Ind 0 E' E' 0 ind 0 0 tan 0 E' E' 0 tan 0 0 CLR' 0
710:  E' E' 0 CLR' 0 0 0 0 E' E'

Prestored Data:

62:  1000 2135003613 1700372300 37410043 3641003032 251331 211714
69:  301335 133335 301345 25413117 25412745 134122 36173337 321537
77:  313242 161715

                              52-NOTES V3N6p3
     For those of us actively involved in the calendar printer compe-
tition, it has been (and may continue to be:  I just thought of a way
to save 24 steps and a little time in the V3N6p3 equally-spaced GTOs...
and who knows, maybe there is a 4 min/year program on someone's drawing
board...) a time-consuming, but stimulating and rewarding contest.  To
the few who already knew the important programming tools, techniques,
and approaches illustrated by 52-NOTES calendar coverage, I apologize
for wasting the space.  But for most, taking the time and devoting the
patience to finding out how and why each of the listed calendar pro-
prams works, and why some are faster than others, will result in signi-
ficantly broadening programming skills, and I hope, justify the 52-
NOTES coverage.  I expect to extend the range of future Friendly Compe-
tition topics, but there aren't many non-trivial problems whose solu-
tions are as universally understood as optimizing a PPC calendar prin-

Book Review: Programmable Calculators - Business Applications; by
Aronofsky, Frame and Greynolds; 203 pp, $8.98, McGraw-Hill 1978.
Tracy Bollinger (864) and James Merrill (693) brought this new book
to my attention, and both report in essence that it would be most use-
ful to those novice users who need more spoon-feeding than the users
manuals provide, but who don't care to go beyond the manuals' program-
ming scope.  The title might be more appropriately worded:  "Learning
How to Program Your TI-58/59/PC-100A For Elementary Business Applica-
tions" since non-TI machines are not covered at all, and non 58/59
very little.  The authors teach at Southern Methodist University, and
write in an easy-to-comprehend textbook style, covering manual as well
as basic programming topics.  While many functions and concepts are
more fully explained than in the 58/59 users manual, there are mis-
leading oversimplifications, and a few technical errors.  For example,
Sec 8-2 titled:  Indirect Instructions covers only indirect stores and
recalls (although the text claims to cover indirect summing as well);
page 143 confuses card protection with program protection, and page 172
incorrectly states that a programmed CP resets all flags.  Important
(to many of us) unannounced features such as the HIR operations and 2-
digit Dsz registers are not mentioned at all.

Tips and Miscellany
     Membership Address Changes:  185:  856th ASA Co APO NY, 09039;
246:  2554 Key Largo Ln Ft Lauderdale, FL 33312; 491:  10571 Kerrigan
Ct Santee, CA 92071; 493:  2800 S Lamb Blvd #181 Las Vegas, NV 89121;
581:  10172 Saluda Ave San Diego, CA 92126; 663:  change 8333 to 7830;
684:  1505 Locust St Pasadena, CA 91106; 755:  1046 Gen Allen Ln West
Chester, PA 19380; 845:  10409 Towlston Rd Fairfax, VA 22030; 997: M E
Holthaus 1181 E Walmut Bldg 5 #6 Carbondale, IL 62901.
     CROM RST Behavior:  Fred Fitzgerald (252) found a code 81 at ML-
19 step 377, and reports that it executes as RST R/S (which I confirm).
Indidently, Fred has made copies of CROM program listings arranged on
8½ X 11 sheets for modules 1 and 7 and will provide these to members,
at $3.00 for one, $4.00 for both.  See V2N5p4 for Fred's current add-
     Structural and Applied Mechanics PPC Applications:  Bob Thacker
(30) has volunteered as a focal point for interested MEs, and wonders
if anyone has tried clock speed-up mods for the 59.

                              52-NOTES V3N6p4
     Last-Step Instruction Execution under Programmed List (58/59/PC):
Jared Weinberger (221) has found that the execution of a last-step rtn
during a programmed List (V2N10p3) applies also to other last-step
instructions.  A sequence of the form:  LA B seq1 rtn LB List seq2 f
seq3 rtn, where f is an instruction located in the last step of the
current partition, on a call to A lists seq2 and instruction f, and
executes instruction f.  If f is rtn, seq1 is executed following the
listing of seq2 f; if f is R/S, execution halts at the last step; if
f is RST, execution continues at step 000; but if f is any other instr-
uction, an error condition is set and the program halts following its
execution.  Composite instructions beginning with f are completable
manually from the keyboard.  If f is C, and if routine C repartitions
memory such that seq3 is executable, a call to A lists seq2 C, executes
C then seq3, seq1.  Members are invited to find new practical applica-
tions for any of this behavior.
     Subroutine Execution from the Printer (52,56,58,59,PC):  Jared
found that with one of the new machines connected to the printer, a
manually keyed SBR PRINT or SBR ADV will initiate processing at defined
Prt or Adv labels, where the PRINT or ADV are the printer keys.  With
the 52, SBR PRINT or SBR ADV execute as GTO Prt or GTO Adv, as might
be expected; with the 56, error states are produced.  While this behav-
ior may have little practical value, it demonstrated another backward
link from the printer to the PPC, akin to PRINT or ADV writing code
into PPC memory when in LRN mode (V1N3p6).
     An All-Digits Generator:  George Hartwig (638) suggests that 80 ÷
81 = is a short way to produce .987654321 .  However, the 13-digit
machines actually produce .9876543209876 and the 11-place 57 produces
.98765432098.  So depending upon use, it might be well to follow the
80÷81= with EE INV EE.
     Strange Pause Effects (58/59):  George found that if while holding
down the GTO key during program execution to pause-display the results
of each step, you key other keys, strange things happen in the display.
Results appear to be digit-value and number-size dependent.
     A Search for Useful CROM Dsz Loops (58/59):  For routines which
loop many times, significant execution time can be saved if the
required code can be found in a CROM sequence (see V2N12p2). For example
a sequence of the form: LA R*n x=t C Dszn A ...LC... will perform
sequential searches through a specified block of registers.  But to do
this acceptably for an unintended application, Lbl C needs to be fol-
lowed by a rtn, with intervening steps that do no harm, and don't
waste too much time.  Members are invited to search CROM listings for
such a sequence, or other potentially useful loops which could save
     Shortened Paper Drive (PC-100/100A):  Fred Fish (606) notes that
the SR-60 manual advises users to precede the first print command with
Adv to preclude reduced paper movement caused by tear-off tension
through the drive mechanism, and that such advice applies also to the
PC-100 and 100A.  I find that the problem is minimized when the tear-
angle is minimized:  pull the paper down across the teeth, not up.
     More on Runaway Motor (V3N3p5):  S H Hartman (920) reports that
the card-drive motor can (always?) be stopped by keying INV Write.
     Linear Programming:  John Hirsh (736) brings up this topic, and
solicits membership interest vis-a-vis PPC applications.

                              52-NOTES V3N6p5
     EE on a 0-digit Mantissa (58/59):  James Merrill (693) notes
that the manually keyed sequence:  777777777 EE 34 = displays as
7.7777778D09, but as 7777777773 when followed by INV EE.  They both
represent the same number in the display register:  7.777777773000D09
which indicates that the 3 following the EE got appended to the man-
tissa.  In general, a manually keyed (or programmed and run) sequence
of the form:  abcdefghi EE j produces the integer:  abcdefghij.
Apparently the EE is ignored as a decapower prefix when the mantissa
is too large for a turn-on display, but small enough to accept another
digit, if such is keyed following the EE.
     A Manual SBR Quirk (58/59):  Izzy Nelken (576) found that a man-
ually keyed SBR 0 x2 in RUN mode squares the display, then executes
code starting at step 000.  This generalizes to the following:  SBR ss
m executes monadic function m on the display, then code starting at
step 0ss; and SBR ss d executes dyadic function d on the display and on
a second operand produced by the code starting at step 0ss.
     Computer Listings of SR-52 Programs:  Roger Cowell (1010) has
written a computer program in HP-2000E BASIC which he runs from a
highschool interactive terminal to print 58/59/PC-type listings from
2-digit SR-52 instruction code inputs.  Write Roger at 115 Fairview
Cir Webster, NY 14580 for details.
     CROM Partitioning:  Arthur Ehrlich (969) reports that steps 164-
166 of LE-13 are 6 Op 17, which when executed in a 58, lock out all of
user memory.  So don't try to call that part of LE-13 from a user pro-
gram in a 58!
     ML-24/25 Precision:  John Mickelsen (990) reports that the statute
to nautical miles conversion factor is inaccurate (good to only 8
places).  Users of these programs should check the values listed on
pages 84 and 86 of the ML Manual against the accepted standards, and
note to how many places they are good.
     Card-Drive Adjustments (59):  Some hardware-knowledgeable users
have attempted to reduce card read/write errors by adjusting a motor
speed pot.  But Robert Cruse (889) quotes a TI source as saying that
"...alignment of the four heads and the azimuth of each..." is more
critical then speed adjustment.  Members are reminded that user-perfor-
med hardware adjustments/mods may invalidate warrantees.  Robert also
reports the existence of "...a new book on the repair and maintenance
of the TI-59 for $11.00", but did not disclose the source or availa-
     CLR for INV EE:  Lou Cargile (625) and Fred Fish (606) suggest
waiting until a CLR can be used safely to return the display to an
INV EE format, saving a step.

     CROM-Call Selective Trace (58/59/PC):  For CROM programs such as
ML-8 which call user-written routines, Jared Weinberger (221) suggests:
LA' Ifflg0 B' Stflg9 B' INV Stflg9 Stflg0 rtn LB'...rtn as a preproces-
sor to the called routine (in this case A') which causes trace-printing
of the routine itself (B') the first time it is called, but not there-
     A General Purpose Integer Routine (V2N12p1):  George Rapasy (981)
devised the sequence:  ...CP x≥t 1' (CE - 1) L1' Int... which is 3
steps shorter than Joel's, protects pending arithmetic, and can be
made to work on all the TI PPCs except the 52.

                              52-NOTES V3N6p6 (end)