STL Programming help again

STL??? · Jul 19, 2007

Hi,
I need to create a FC/FB to sort through DB error messages and prioritise them in the order of Importance. the values generated(x5) will be the basis for the display Text using the highest number as the highest priority.

I wrote a single block which when called in seperate instances (x5) does what i want,but i'm trying to combine it all into one call.

I'm having problems ironing out the issues with the code and tightening it up and would apprieciate some help!

Problem 1 - When DBX0.0 is set the CPU stops

Problem 2 - I've tried to add range protection to the Loop_index, but each way i try either stops the cpu or causes the Loop not to work!

FUNCTION "Alarm generator V3" : VOID

    TITLE =

    VERSION : 0.1

    

    

    VAR_INPUT

      Alarm_DB : BLOCK_DB ;    

      DB_Length : INT ;    

    END_VAR

    VAR_IN_OUT

      Loop_Index : INT ;    

    END_VAR

    BEGIN

    NETWORK

    TITLE =Check Range 

    

          L     #DB_Length; 

          L     0; // if zero then no further bits to interrogate

          <=I   ; 

          BEC   ; 

    

          OPN   #Alarm_DB; // Open Alarm Datablock

    NETWORK

    TITLE =Scan the Alarm DB Looking for Active Faults

    //

    //

    //

          L     #DB_Length; // Total number of Alarm bits to scan

    TOP:  T     #Loop_Index; 

          +     -1; // align index to array i.e dbx0.0 = ALARM[1]

          LAR1  ; 

    

          A     DBX [AR1,P#0.0]; // Scan for match

          JC    ERR1; // Jump out if match found

          L     #Loop_Index; 

          LOOP  TOP; // minus 1 from index and re-scan until match or zero achieved

    

    //No match found

          L     0; 

          T     #Loop_Index; 

          JU    end; 

    

    //Match found

    ERR1: L     #Loop_Index; 

          T     DBW [AR2,P#14.0]; // Point to beginning of Text storage (DBW14)

    

          +AR2  P#2.0; // increment pointer to transfer additional matches to next word (max 5) 

          TAK   ; // move index back to accu 1

          JC    TOP; 

    

    end:  NOP   0; 

    

    

    

    

    

    

    END_FUNCTION

STL??? · Jul 19, 2007

Going back to basics, i can get it to work:



        OPN   DB     2

        L     50

  

  Top:  T     #Loop_Index

        +     -1

        LAR1  

  

        A     DBX [AR1,P#0.0]

        JC    ALM

  

        L     #Loop_Index

        LOOP  Top

  

        L     0

        T     #Loop_Index

        JU    CLR

  

  ALM:  L     #Loop_Index

        T     DBW [AR2,P#14.0]

  CLR:  NOP   0

Problems are to increment the + ar2 offset and re-enter the Loop were it left off!

STL??? · Jul 19, 2007

Right! this works but its a bit of a jump mess...

        OPN   DB     2

        L     50

  

  Top:  T     #Loop_Index

        +     -1

        LAR1  

  

        A     DBX [AR1,P#0.0]

        JC    ALM

  

        L     #Loop_Index

        LOOP  Top

  

        L     0

        T     #Loop_Index

        JU    End

  

  ALM:  L     #Loop_Index

        T     DBW [AR2,P#14.0]

  // rescan

  

        L     1

        <=I   

        JC    End

  

        +AR2  P#2.0

        TAK   

        +     -1

        JU    Top

  

  

  End:  NOP   0

not sure i understand why i need the + -1 (in red) when 1 is removed at label Top, however without it the 5 word registers get filled with the same result!

PeterW · Jul 19, 2007

where do you preset AR2?, I thought AR2 normally pointed to the start of data area for an instance DB.

STL??? · Jul 19, 2007

Good point, i hadnt thought about that, i could initialise it before the loop starts, I used a FC to remove any issues with IDB and AR2.

PeterW · Jul 19, 2007

The Loop decreases the variable, all the way to 0 I believe.

In yiur original block, if you subtracted 1 from the DB_Length before the label TOP it should be OK.

i.e.

Code:

[/size][/font]
		  L	 #DB_Length; // Total number of Alarm bits to scan
		  +	 -1; // align index to array i.e dbx0.0 = ALARM[1]

	TOP:  T	 #Loop_Index; 
		
		  LAR1  ;

I would also at the start do the following have temp called AR2_Store and save AR2 into it at the start, then set AR2 to zero and at the end recover AR2 before leaving the block.

STL??? · Jul 19, 2007

Hi Peter,
I was going to store/restore AR2 in the final version of the code and revert back to a variable for DB number and Scan index,But at the moment i'm just trying to see if i have removed all the issues with it.

Ill try moving the -1 back and see how that goes!

Cheers Steve

aikona · Jul 19, 2007

Hi

you want to scan bits right from top to bottom

OPN #Alarm_DB; // Open Alarm Datablock
L #DB_Length; // Total number of Alarm bits to scan
T #Loop_Index;
TOP:L #Loop_Index; // make this 32 bits wide

A DBX [#Loop_Index]; // Scan for match
JC ERR1; // Jump out if match found

L #Loop_Index;
DEC 1
LOOP TOP; // minus 1 from index and re-scan until match or zero achieved

L 0;
T #Loop_Index;

JU end;
ERR1: L #Loop_Index // is value in bits
INC 112 // Is offset but must be bits so 14x8
T DBW[#Loop_Index]
// T DBW [AR2,P#14.0]; // Point to beginning of Text storage (DBW14)

try this ... could still be full of bugs . but I prefer the
L or T DBW or DBX [Pointer in double and bit]

ie L 20
SLW 3
T MD200 Call DBxx
L DBW[MD200] to load DW200

L 20
+1
T MD200
Call DBxx
A DBX[MD200] to 'and' DBxx.DBX20.1

Bye

Eric

STL??? · Jul 19, 2007

Its the index number of the alarm bit i'm interested in, to display as follows:

jacekd · Jul 19, 2007

To make the code even more compact try to remove Loop_Index:

LAR2 p#0.0 //clean up - don't forget to store it before
OPN DB 2
L 50
+ -1

Top: LAR1

A DBX [AR1,P#0.0]
JCN CONT // continue

T DBW [AR2,P#14.0]
+AR2 P#2.0

CONT: LOOP Top

End: NOP 0

BTW, the red "+ -1" you need because you jump over the "LOOP" command

Jeebs · Jul 20, 2007

        OPN   DB     2

          L     50

    

    Top:  T     #Loop_Index  // Loop_index is 50

          +     -1  

          LAR1  

    

          A     DBX [AR1,P#0.0]

          JC    ALM

    

          L     #Loop_Index  

          LOOP  Top

    

          L     0

          T     #Loop_Index

          JU    End

    

    ALM:  L     #Loop_Index  // Loop_index is still 50

          T     DBW [AR2,P#14.0]

    // rescan

    

          L     1

          <=I   

          JC    End

    

          +AR2  P#2.0

          TAK     // Loop_index is still 50

          +     -1  // Needed to simulate the LOOP instruction, that decrements the value automatically

          JU    Top

    

    

    End:  NOP   0

Thats why you need the + -1. Or did I miss anything?

Jeebs

PeterW · Jul 20, 2007

Jeebs said:



 

The Loop instruction decrements whats in the accumulator by 1. The reason he had to decerement it at that point is because he jumped over the loop instruction.

STL??? · Jul 20, 2007

jacekd,

To make the code even more compact try to remove Loop_Index:

LAR2 p#0.0 //clean up - don't forget to store it before
OPN DB 2
L 50
+ -1

Top: LAR1

A DBX [AR1,P#0.0]
JCN CONT // continue

T DBW [AR2,P#14.0]
+AR2 P#2.0

CONT: LOOP Top

End: NOP 0

BTW, the red "+ -1" you need because you jump over the "LOOP" command

Thanks for posting that, it has given me a different perspective on things, however for some reason (which i cant figure out)it ignores DBX0.0 when set and instead assigns the value of 1 to dbx0.1 which should be 2?

Thanks to everyone so far who has helped me with this.

L D[AR2P#0.0] · Jul 20, 2007

STL??? said:
however for some reason (which i cant figure out)it ignores DBX0.0 when set and instead assigns the value of 1 to dbx0.1 which should be 2?

You really mean assigns 1 to DBW14 don't you ?

Did you want to search from the bottom of the list backwards, or is this just the way it turned out.

jacekd · Jul 20, 2007

STL??? said:
...however for some reason (which i cant figure out)it ignores DBX0.0 when set and instead assigns the value of 1 to dbx0.1 which should be 2...

My fault. Some corrections below.

LAR2 p#0.0 //clean up - don't forget to store it before
OPN DB 2
L 50

Top: + -1
LAR1
+ 1
A DBX [AR1,P#0.0]
JCN CONT // continue

T DBW [AR2,P#14.0]
+AR2 P#2.0

CONT: LOOP Top

End: NOP 0

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