Again, why not query system symbol &LWDAY, instead of trying to calculate?
https://www.ibm.com/docs/en/zos/3.1.0?topic=1-operation
Here is some sample code from IBM that could be used as a starting point, and
likely simplified
Set up the area that is to contain the substitution text. The caller does not
provide a symbol table or time stamp.
LA 3,MYSYMBP
USING SYMBP,3
XC SYMBP(SYMBP_LEN),SYMBP Initialize to zero
LA 4,PATTERN Address of pattern
ST 4,SYMBPPATTERN@ Save in SYMBP area
LA 4,L'PATTERN Length of pattern
ST 4,SYMBPPATTERNLENGTH Save in SYMBP area
LA 4,TARGET Address of target
ST 4,SYMBPTARGET@ Save in SYMBP area
MVC TARGETLENGTH,=A(L'TARGET) Set length of target
LA 4,TARGETLENGTH Address of target length
ST 4,SYMBPTARGETLENGTH@ Save in SYMBP area
*
* Because the caller did not provide a symbol table, we know that
* we are using only the system symbols provided by MVS. Since we have
* initialized the entire SYMBP area to 0, we do not have to
* set up the SYMBPSYMBOLTABLE@ field.
*
* Because the caller did not provide a timestamp, and because we
* have initialized the entire SYMBP area to 0, we do not have to
* set up the SYMBPTIMESTAMP@ field.
*
LA 4,RETURNCODE Address of return code
ST 4,SYMBPRETURNCODE@ Save in SYMBP area
DROP 3
⋮
*
* Note that to avoid the assembler substituting
* for &SYSNAME, &YYMMDD, &HHMMSS, two ampersands are specified.
* The resulting pattern, then, is actually
* USERID.&SYSNAME..D&YYMMDD..T&HHMMSS
*
PATTERN DC C'USERID.&&SYSNAME..D&&YYMMDD..T&&HHMMSS'
DYNAREA DSECT
DS 0F
MYSYMBP DS CL(SYMBP_LEN) SYMBP area
RETURNCODE DS F Return code
TARGETLENGTH DS F Length of target
TARGET DS CL80 An area big enough to hold the target no
* matter what is substituted. Since &DATE
* and &TIME are not used, it need be no
* longer than the pattern area.
ASASYMBP , Mapping of SYMBP area
Dave Jousma
Vice President | Director, Technology Engineering
From: IBM Mainframe Discussion List <[email protected]> on behalf of
David Spiegel <[email protected]>
Date: Friday, April 18, 2025 at 11:03 AM
To: [email protected] <[email protected]>
Subject: Re: Day of week from a program
Hi Ituriel,
Please send me a copy to [email protected]
Thanks and regards,
David
On 2025-04-18 10:25, Ituriel do Neto wrote:
> Hello,
>
> I do have a very old assembler macro that returns the day of the week when
> the date (DDMMCCYY) is passed. Please let me know if you want it.
>
>
> Best Regards
>
> Ituriel do Nascimento Neto
> z/OS System Programmer
>
>
>
>
>
>
> Em quinta-feira, 17 de abril de 2025 às 20:31:59 GMT+2, Paul Gilmartin
> <[email protected]> escreveu:
>
>
>
>
>
> On Thu, 17 Apr 2025 18:54:28 +0200, salva wrote:
>
>> So, remember to add CVTLSO to the STCK value if needed. Also, CVTLDTO for
>> local time.
>>
> Those suffice for only the present time. The better an answer,
> which IBM inexplicably shuns, although it's used by nearly all
> mobile and desktop devices is:
> <https://urldefense.com/v3/__https://www.iana.org/time-zones__;!!MwwqYLOC6b6whF7V!nTQebB8T-IS9RUqyk60saSTSZL2BMUgh60QOXesjk6nAuowOO_0_CEfaeVpBwLbhsJWfO0E75jMl3cWkFnLMeTo5haaPwqPB7z0$<https://urldefense.com/v3/__https:/www.iana.org/time-zones__;!!MwwqYLOC6b6whF7V!nTQebB8T-IS9RUqyk60saSTSZL2BMUgh60QOXesjk6nAuowOO_0_CEfaeVpBwLbhsJWfO0E75jMl3cWkFnLMeTo5haaPwqPB7z0$>>
>
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