Re: [Mspgcc-users] assembler vs extension words

[Peter B. <pa...@gm...>]

Just to note: this list doesn't transport patches.  Sorry.

Peter (still lurking, no longer active)

On Wed, Feb 3, 2016 at 6:29 AM, Nick Clifton <ni...@re...> wrote:

> Hi David,
>
> I am having some trouble using the rpt functionality of the CPUX. While
>> attempting to assemble some code for the msp430fr5969 I was surprised
>> with this error:
>>
>> repeat count cannot be used with rrux
>>
>> In response to:
>> rpt r15 { rrux.w r6
>>
>
>
> Oops - this is definitely a bug.  You should report it ... :-)
>
> The problem is that RRUX is a synthetic instruction, and GAS is
> incorrectly checking it as if it were RRUM, which does not accept a RPT
> count.
>
> After some fiddling around I was able to
>> generate code that worked but I had to bang it in using .word
>> directives. objdump produced:
>>
>> rpt r15 { rrcx.w        r6
>>
>> Which is almost but not quite correct because it ignores the little
>> detail of the extension word having the ZC bit set.
>>
>
> True - this is really the same bug.  GAS is not encoding RRUX correctly,
> so it is not being decoded correctly either.
>
>
> Which brings up another problem. Not only is the use of rpt not
>> documented for the GNU assembler,
>>
>
> This is because there is no real documentation from TI describing how the
> RPT pseudo-instruction ought to work.  I assumed that they must have an
> "assembler programming for the MSP430 " guide somewhere that described this
> feature, and that I have just not seen it.  In my opinion the GNU assembler
> documentation should not be documenting features that are supposed to be a
> standard part of the architecture's assembler.
>
> there isn't any hint of how to set the
>> ZC bit in the extension word.
>>
>
> It has to be through the use of different opcode mnemonics, ie RRUX vs
> RRCX.
>
>
> slau367 is a bit thin in describing the repeat feature as well. It
>> barely gets a mention in the description of the extension word and
>> appears a few times in examples. Other than that there is nothing.
>>
>
> Agreed - it is very frustrating.
>
> There is also very little documentation on synthetic instructions and how
> they ought to be implemented.
>
> Anyway, please try out the attached patch and let me know if it works for
> you.
>
> Cheers
>   Nick
>
>
>
>
>
> ------------------------------------------------------------------------------
> Site24x7 APM Insight: Get Deep Visibility into Application Performance
> APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month
> Monitor end-to-end web transactions and take corrective actions now
> Troubleshoot faster and improve end-user experience. Signup Now!
> http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140
> _______________________________________________
> Mspgcc-users mailing list
> Msp...@li...
> https://lists.sourceforge.net/lists/listinfo/mspgcc-users
>
>