Am 05.02.2014 23:55, schrieb Bernd Oppolzer:
Am 05.02.2014 13:25, schrieb Shmuel Metz (Seymour J.):
In <[email protected]>, on 02/05/2014
at 12:39 AM, Bernd Oppolzer <[email protected]> said:
The OP attached the complete source code of his module
with his first mail.
Sorry; I missed that. Where is ITMAP defined?
ITMAP is not defined in the piece of code we got,
but from the code it is obvious that ITMAP is a table (or string)
of bits and that the parameters on entry define, which particular bit
is the target bit of the operation:
FORCEONE DS 0H
PACK T@SAVE,CDSTOR FIND BIT DISPLACEMENT
DP T@SAVE,=P'8' FOR STORE NUMBER
ZAP BYTE,T@SAVE(7) QUOTIENT IS BYTE DISPLACEMENT
ZAP BIT,T@SAVE+7(1) REMAINDER IS BIT DISPLACEMENT
the problem is, that the comments don't fit well
to the actions carried out, for example
L R4,BYTE BIT MAP DISPLACEMENT
LA R6,ITMAP(R4) BYTE COMPARE ADDRESS
SR R5,R5 CLEAR WORK REGISTER
IC R5,BIT TEST BIT
EX R5,XI@TM TEST THE BIT
BR R2 RETURN
*
XI@TM XI 0(R6),0 TURN OFF STORE BIT
my comments to the comments:
BYTE COMPARE ADDRESS - nonsense, there is no compare
TEST BIT - there is no TEST of a bit
TURN OFF STORE BIT - if off, the bit will be turned ON, not off
XI@TM - why the TM suffix? there is no TM
misleading comments are worse than no comments, IMHO
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sorry for posting the uncomplete source ... of course there is some
CVB and TR work done to the variables BIT and BYTE between the
two excerpts, which is not shown. Please refer to the attachment of
the OP, if you have any doubts about this.
Kind regards
Bernd
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