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I've a naive question about the PL/1 F we
have onboard on MVS3.8j.

Forgive me, I'm trying to write code for
going from a single character to its EBCDIC
code and viceversa.

The first problem should be solved by this code
fragment:

ECODE:
PROCEDURE ( CHR ) RETURNS(FIXED BIN(15));
DCL CHR CHARACTER(1);
DCL CODE FIXED BIN(15);

CODE = UNSPEC ( CHR );
RETURN ( CODE );
END ECODE;

which seems to work correctly.

But I can't see a way for going back from the EBCDIC
code to a single character string, using only PL/1 F.

For what I can understand in modern PL/1 compilers
there are specific builtin functions implemented, but,
reading the original IBM manuals, I can't see any simple
way to solve the problem.

Any advice?

Peppe.

Isn't UNSPEC not also a pseudo-variable, so that it can also be used on the left-had side of an assignment, e.g.:

UNSPEC ( CHR ) = CODE ;

Cheers,

Peter

On Tue, 7 Jul 2020, Peter Jansen via groups.io wrote:

Isn't UNSPEC not also a pseudo-variable, so that it can also be used on the left-had
side of an assignment, e.g.:
UNSPEC ( CHR ) = CODE ;

Yep, it does.

Unfortunately, FIXED BIN(15) is half word,
i.e. two bytes in PL/1 F.

My guess

UNSPEC ( CHR ) = CODE

convert just the most significant CODE byte, leading
to a wonderful ZERO character.

If I got it right, this routine should do the trick:

ECHAR:
PROCEDURE ( CODE ) RETURNS(CHARACTER(1));
DCL CODE FIXED BIN(15);
DCL CHR CHARACTER(1);
DCL B BIT(16);
B = UNSPEC(CODE);
UNSPEC(CHR)=SUBSTR(B,9,8);
RETURN ( CHR );
END ECHAR;

Wondering if there are better ways.

Peppe.

On Tue, 7 Jul 2020, Giuseppe Vitillaro wrote:

On Tue, 7 Jul 2020, Peter Jansen via groups.io wrote:

Isn't UNSPEC not also a pseudo-variable, so that it can also be used on the left-had
side of an assignment, e.g.:
UNSPEC ( CHR ) = CODE ;

Yep, it does.

Unfortunately, FIXED BIN(15) is half word,
i.e. two bytes in PL/1 F.

My guess

UNSPEC ( CHR ) = CODE

convert just the most significant CODE byte, leading
to a wonderful ZERO character.

If I got it right, this routine should do the trick:

ECHAR:
PROCEDURE ( CODE ) RETURNS(CHARACTER(1));
DCL CODE FIXED BIN(15);
DCL CHR CHARACTER(1);
DCL B BIT(16);
B = UNSPEC(CODE);
UNSPEC(CHR)=SUBSTR(B,9,8);
RETURN ( CHR );
END ECHAR;

Wondering if there are better ways.

Peppe.

Well, this is actually a little bit better:

ECHAR:
PROCEDURE ( CODE ) RETURNS(CHARACTER(1));
DCL CODE FIXED BIN(15);
DCL CHR CHARACTER(1);

UNSPEC(CHR)=SUBSTR(UNSPEC(CODE),9,8);
RETURN ( CHR );
END ECHAR;

I guess the UNSPEC(CHR) can't be moved inside
the RETURN statement? It doesn't work for what
I've verified.

Peppe.

Try the following code
//HERC01P JOB MSGCLASS=A,MSGLEVEL=(1,1)???????????
//P1? EXEC PL1LFCG????????????????????????????????
//PL1L.SYSIN DD *?????????????????????????????????
?TEST:PROC OPTIONS(MAIN);?????????????????????????
????? DECLARE 1 NUM_CHAR??????? FIXED BINARY(15),?
????????????? 1 CHAR_2???? DEFINED NUM_CHAR,??????
??????????????? 2 (CHAR_HIGH,CHAR_LOW)????????????
?????????????????????????? CHAR(1);???????????????
????? NUM_CHAR=0;?????????????????????????????????
????? CHAR_LOW = 'A';?????????????????????????????
????? PUT SKIP LIST(NUM_CHAR,CHAR_LOW);???????????
????? PUT SKIP LIST('NUMBER','CHAR');?????????????
????? DO NUM_CHAR=240 TO 249;?????????????????????
???????? PUT SKIP LIST(NUM_CHAR,CHAR_LOW);????????
????? END;????????????????????????????????????????
?END TEST;????????????????????????????????????????
If you submit it, this is what you get:
????? 193?????????????? A
NUMBER????????????????? CHAR
????? 240?????????????? 0
????? 241?????????????? 1
????? 242?????????????? 2
????? 243?????????????? 3
????? 244?????????????? 4
????? 245?????????????? 5
????? 246?????????????? 6
????? 247?????????????? 7
????? 248?????????????? 8
????? 249?????????????? 9

On Tue, 7 Jul 2020, Ed Liss wrote:

Try the following code
//HERC01P JOB MSGCLASS=A,MSGLEVEL=(1,1)
//P1 EXEC PL1LFCG
//PL1L.SYSIN DD *
TEST:PROC OPTIONS(MAIN);
DECLARE 1 NUM_CHAR FIXED BINARY(15),
1 CHAR_2 DEFINED NUM_CHAR,
2 (CHAR_HIGH,CHAR_LOW)
CHAR(1);
NUM_CHAR=0;
CHAR_LOW = 'A';
PUT SKIP LIST(NUM_CHAR,CHAR_LOW);
PUT SKIP LIST('NUMBER','CHAR');
DO NUM_CHAR=240 TO 249;
PUT SKIP LIST(NUM_CHAR,CHAR_LOW);
END;
END TEST;

If I got it right not different from
a C union.

Nice trick ;-)

Thanks, Peppe.