Path: utzoo!attcan!uunet!mcvax!enea!kth!draken!bmc1!kuling!ewerlid
From: ewerlid@kuling.UUCP (Ove Ewerlid)
Newsgroups: comp.sys.nsc.32k
Subject: Assembler syntax of CINV in the 32532
Keywords: assembler
Message-ID: <828@kuling.UUCP>
Date: 12 Sep 88 22:27:08 GMT
Reply-To: ewerlid@kuling.UUCP (Ove Ewerlid)
Organization: Dept. of Computer Systems, Uppsala University, Sweden
Lines: 37


 This may seem like a rather odd question but as I'm currently working on
a ns32k-assembler (porting GAS actually) the following question arose:

Why has national decided on a new syntax form for optionlists for the ns32532?
(This may not be the case, as the datasheet I have is marked preliminary.)
In APPENDIX C, page 89 of this datasheet the CINV instruction is described.

Assembler syntax:   CINV options,src

 where options are combinations of A,I or D separated by ','
 ie there are 3 bits in the machine instruction that are to be set
 if the corresponding letter EXIST in the operand(s).

	compare this with the old instruction SETCFG

Assembler syntax:   SETCFG [option list]
 
 where option-list is combinations of C,M,F or I separated by ','
 this list is enfolded within two squarebrackets.
 Ie there are 4 bits in the machine instruction that are to be set
 if the corresponding letter EXIST in the operand. (just one operand)


 Now, at the machine level those instructions have the same needs.
Ie the setting of a bitmap of options according to the letters in the operands.
I think this should be reflected with two identical syntax-forms and not
introduce a second form that leads to another specialcase in the assembler.
Furthermore I think that the syntax of SETCFG gives a cleaner modell for
operand disassembly in the assembler. This means that the CINV should have
exactly two operands and not 1 to 4.

 Again, the above may not be the case if my preliminary datasheet not is up to
date and as I think like a man that is writeing an assembler I may have missed
some subtle point that justifies the new syntax.

/Ove