15C programming question

[Eric Zoob]

Routine A dimensions matrices A,B, and sets result to C.
Routine E multiplies AxB.

Without the second (repeated) RTN on line 22, the program does not return to 000, but will continue through and multiply AxB. What am I doing wrong here?

001- 42,21,11 LBL A

002- 2

003- 36 ENTER

004- 2

005- 42,23,11 DIM A

006- 2

007- 36 ENTER

008- 1

009- 42,23,12 DIM B

010- 42,26,13 RESULT C

011- 42,16,1 MATRIX 1

012- 0

013-u 44 11 STO A

014- 1

015-u 44 11 STO A

016- 1

017- 16 CHS

018-u 44 11 STO A

019- 0

020-u 44 11 STO A

021- 43 32 RTN

022- 43 32 RTN

023- 42,21,15 LBL E

024- 45,16,11 RCL MATRIX A

025- 36 ENTER

026- 45,16,12 RCL MATRIX B

027- 20 Multiply

028- 43 32 RTN

Edited: 27 Mar 2012, 2:08 p.m.

[Kiyoshi Akima]

Step 20 follows the "do if true" paradigm of the conditional and looping commands. It does the STO, increments the counters, and skips the next step if it had gone past the matrix boundary.

[Eric Zoob]

Thanks. I found it in the manual. That's a very nice feature, actually.

[Tom Sauntry]

Pardon my ignorance, but what are the lower-case "u"s preceding the 44 11 STO commands in the listing.

[Gene Wright]

means they were keyed in while in USER mode.

Changes the behavior of some commands related to matrix, etc.

[C.Ret]

Bonjour,

This topic is a good reason, actually a good excuse, to practice and remind me some of my HP-15C's code.

That's how I read the proposed code and interprets its progress. Feel free to comment and report any oversight or misinterpretation.

  Key Code       MNEMOMICS              Merge Commands     Remarks

001-42,21,11     LBL A                 "A"                 Sub-program "A"

002-       2      2

003-      36      ENTER

004-       2      2

005-42,23,11      DIM A                 (2,2) DIM A        Dimension Data Matrix A to 2x2

006-       2      2

007-      36      ENTER

008-       1      1

009-42,23,12      DIM B                 (2,1) DIM B        Dimension Data Matrix B to 2x1

010-42,26,13      RESULT C		Result in C        Designates Matrix C for storing result

011-42,16, 1      MATRIX 1              Matrix Entry       Restart entry from home position (1,1)

012-       0      0

013-u 44  11      STO A			A(1,1) <--  0      Matrix A Entry

014-       1      1

015-u 44  11      STO A                 A(1,2) <--  1

016-       1      1

017-      16      CHS

018-u 44  11      STO A                 A(2,1) <-- -1

019-       0      0

020-u 44  11      STO A                 A(2,2) <--  0

021-  43  32      RTN                                     ............ step skiped since 'End of Matrix reached' (roll over)

022-  43  32      RTN			End of "A"

023-42,21,15     LBL E                "E"                 Sub-Program "E"

024-45,16,11      RCL MATRIX A          

025-      36      ENTER                                   ? ? ?

026-45,16,12      RCL MATRIX B

027-      20      ×                     C <-- A × B       Matrix Product

028-  43  32      RTN                   End of "E"

[Luiz C. Vieira (Brazil)]

Hi;

I'd just add a few remarks, if you allow me to:

  Key Code       MNEMOMICS              Merge Commands     Remarks

001-42,21,11     LBL A                 "A"                 Sub-program "A"

002-       2      2

003-      36      ENTER

004-       2      2                   (unnecessary)

005-42,23,11      DIM A                 (2,2) DIM A        Dimension Data Matrix A to 2x2

006-       2      2                   (unnecessary)

007-      36      ENTER               (unnecessary)

008-       1      1

009-42,23,12      DIM B                 (2,1) DIM B        Dimension Data Matrix B to 2x1

010-42,26,13      RESULT C		Result in C        Designates Matrix C for storing result

011-42,16, 1      MATRIX 1              Matrix Entry       Restart entry from home position (1,1)

012-       0      0

013-u 44  11      STO A			A(1,1) <--  0      Matrix A Entry

014-       1      1

015-u 44  11      STO A                 A(1,2) <--  1

016-       1      1                    (unnecessary)

017-      16      CHS

018-u 44  11      STO A                 A(2,1) <-- -1

019-       0      0

020-u 44  11      STO A                 A(2,2) <--  0

021-  43  32      RTN                                     ............ step skiped since 'End of Matrix reached' (roll over)

022-  43  32      RTN			End of "A"

023-42,21,15     LBL E                "E"                 Sub-Program "E"

024-45,16,11      RCL MATRIX A          

025-      36      ENTER                                   ? ? ?

026-45,16,12      RCL MATRIX B

027-      20      ×                     C <-- A × B       Matrix Product

028-  43  32      RTN                   End of "E"

Step #4: after [ENTER] both X and Y registers already filled with 2.00, no need to enter again;

Steps #6 and #7: Same as above

Step #16: there is a copy of 1 still in the X-register, a single CHS suffices to let -1 in the X-register

And you are correct: step #25 is not needed.

Since the elements and the indexes for the matrices are not used after their contents are set, reusing them instead of introducing them back once they are still in the memory stack reduces the number of program steps. And allow the extra few bytes to be used in other programs.

Cheers.

Luiz (Brazil)

Edited: 28 Mar 2012, 5:52 a.m.

[C.Ret]

You are welcome ! :-)