SV: [Icc-avr] Compiler bug?
Richard
richard-lists at imagecraft.com
Mon May 7 00:43:22 PDT 2007
Sorry if I sound accusatory. I really just meant to ask for more
clarification. Here's what I recommend you to do, either create the
smallest compilable program, or even just document what you have, with
things like
// ppgAcDiff is XYZ at this point
ppgAcDiff = ppgAcDiff/acGain;
ppgAcDiff++;
// ppgAcDiff is ABC here
subtractTotalDiffFiltered = S_ShortFilter(ppgAcDiff, &filtMem[channel],
filterdjup, &firFiltMem[channel]);
// When S_ShortFilter is entered, the first argument has QWE instead of ABC
Especially if you trim it down to a compilable function, with this type of
description, I can easily say something like, yes, it sounds like a bug, or
no, it's just the way the C semantic is, or I can compile it, and say, the
code looks OK or not.
In other words, just describe what you see. It makes it easier to determine
what questions I need to ask. For example, in this email, you said:
>The result is not the same, not even the result from the function there
>the result from the division is used.
>
>As John said, the move should be unnecessary but in my testing, the result
>from the function did change. I will try to use a test function that do
>something simple and see the result. I get back. Maybe the problem is in
>the function.
"The result is not the same" Which result? If you just point to the code
and say, and result should be XYZ but AVR Studio shows ABC, it would be
more useful.
Hope this clarifies.
At 11:45 PM 5/6/2007, Bengt Ragnemalm wrote:
>Please Richartd, try to be patient with me. I am just trying to get some
>help and am truly sorry if you are feeling “spammed”. I will try to be
>more precise in the future.
>
>My problem is that I do not get any result from the simple division
>“ppgAcDiff = ppgAcDiff/acGain;”
>
>As I said, I always am very careful about accusing the compiler as it is
>not normally the cause and especially not for simple things like this. But
>in this case I am running it in Studio and after just adding the
>: ppgAcDiff++; (and also a ppgACDiff--;) The result is not the same,
>not even the result from the function there the result from the division
>is used.
>
>As John said, the move should be unnecessary but in my testing, the result
>from the function did change. I will try to use a test function that do
>something simple and see the result. I get back. Maybe the problem is in
>the function.
>
>And Richard again, I am used to ask all kind of questions here, one more
>stupid than the other, and I am used to get great support from you or
>anyone else here so I am not so used that you being so angry with me.
>Could it possible be that you have little black devil on your shoulder
>that triggers on the “compiler bug” condition? It that is so, please use a
>frying pan or something and smash it down, I do not want to upset anyone
>(maybe I did so right now which I didn’t intended either)
>
>Sincerely
>Bengt Ragnemalm
>
>
>----------
>Från: icc-avr-bounces at imagecraft.com
>[mailto:icc-avr-bounces at imagecraft.com] För John Baraclough
>Skickat: den 4 maj 2007 18:27
>Till: benra at imt.liu.se; Discussion list for ICCAVR and ICCtiny Users. You
>do NOT need tosubscribe to icc-announce if you are a member of this.
>Ämne: Re: [Icc-avr] Compiler bug?
>
>Hi Bengt,
>
>I assume the function at 0x00000A68 in your first listing is 'div16s', in
>which case the result is returned in R16/R17. That being so, then the
>first parameter being passed to the function
>
>S_ShortFilter(ppgAcDiff, &filtMem[channel], filterdjup, &firFiltMem[channel]);
>
>is already in the correct register pair and doesn't need to be moved.
>Sorry, but I don't think he problem is with the compiler.
>
>All the best for now,
>John
>
>
>At 13:44 04/05/2007, you wrote:
>
>Hi.
>
>I know that I am usually wrong about this but this looks like a compiler
>bug to me. Please have look.
>
>ppgAcDiff and acGain are signed short.
>
>This simple line didn’t do anything so I checked the assembler. Actually
>this is very similar to my previous problem but this time the variable is
>used at the line right after. Just to provoke, I inserted a simple ++ in
>between and yes, now the result is saved. What is going on here?
>
>ppgAcDiff = ppgAcDiff/acGain;
>
>
>411: ppgAcDiff = ppgAcDiff/acGain;
>+0000020D: 019C MOVW R18,R24 Copy register pair
>+0000020E: 0187 MOVW R16,R14 Copy register pair
>+0000020F: 940E0A68 CALL 0x00000A68 Call subroutine
>414: subtractTotalDiffFiltered = S_ShortFilter(ppgAcDiff,
>&filtMem[channel], filterdjup, &firFiltMem[channel]);
>
>
>
>411: ppgAcDiff = ppgAcDiff/acGain;
>+0000020D: 019C MOVW R18,R24 Copy register pair
>+0000020E: 0187 MOVW R16,R14 Copy register pair
>+0000020F: 940E0A6D CALL 0x00000A6D Call subroutine
>+00000211: 0178 MOVW R14,R16 Copy register pair
>412: ppgAcDiff++;
>+00000212: 01C7 MOVW R24,R14 Copy register pair
>+00000213: 9601 ADIW R24,0x01 Add immediate to word
>+00000214: 017C MOVW R14,R24 Copy register pair
>414: subtractTotalDiffFiltered = S_ShortFilter(ppgAcDiff,
>&filtMem[channel], filterdjup, &firFiltMem[channel]);
>
>/Bengt
>________________________________________________________________
>
>Bengt Ragnemalm Tel +46 13 22 24 97
>
>Research engineer FAX: +46 13 10 19 02
>
>Linköpings
>Universitet
><mailto:bengt.ragnemalm at imt.liu.se>mailto:bengt.ragnemalm at imt.liu.se
>
>Inst. för Medicinsk Teknik
>Internet: <http://www.imt.liu.se/>http://www.imt.liu.se
>
>S-581 85 Linköping SWEDEN
>
>
>
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// richard (This email is for mailing lists. To reach me directly, please
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