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Gavin Pinto
Joined: 18 Oct 2009
Posts: 27
Location: Australia
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| Errors in the CCS Webpage code |
 Posted: Thu Feb 04, 2010 9:17 pm |
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I believe there are a few errors in code below. So please verify my findings so I will send feedback to CCS official support later to correct the oversight. Since it is not from the examples folder provided with the compiler and does not violate posting guidelines, I posted it here. It is on a CCS webpage. If CCS or their moderator feels it violates posting guidlines or copyright, I will delete it.
The code is from the following URL
http://www.ccsinfo.com/content.php?page=flexconst
A more complex example that creates an array of pointers to constant strings:
| Code: |
ROM char *strings[] =
{
"HELLO",
"WORLD",
"CONST",
"STRINGS"
};
/*
Access the above const pointers
*/
ROM char *ptr;
while (i = 0; i < (sizeof(strings) / sizeof(const char *)); i++)
{
ptr = strings[i];
printf("%s", ptr);
} |
_________________
Clear Logic
Last edited by Gavin Pinto on Thu Feb 04, 2010 11:34 pm; edited 5 times in total |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Thu Feb 04, 2010 9:25 pm |
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In questions like this,
1. Post your PIC.
2. Post your compiler version. We don't remember your version
from your previous threads.
3. Post a test program that demonstrates the problem.
4. Completely say what your problem is. Don't make it a mystery. |
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Gavin Pinto
Joined: 18 Oct 2009
Posts: 27
Location: Australia
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| Posted: Thu Feb 04, 2010 9:34 pm |
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| PCM programmer wrote: |
4. Completely say what your problem is. Don't make it a mystery. |
Well just reading the code you should see some problems. I don't think a compiler is needed in the initial analysis.
Later we may look at the compiler output.
_________________
Clear Logic
Last edited by Gavin Pinto on Thu Feb 04, 2010 9:40 pm; edited 1 time in total |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Thu Feb 04, 2010 9:39 pm |
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| OK. Someone else can help on this thread. |
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Gavin Pinto
Joined: 18 Oct 2009
Posts: 27
Location: Australia
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| Posted: Thu Feb 04, 2010 9:43 pm |
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| PCM programmer wrote: | | OK. Someone else can help on this thread. |
Ok I will help with my own thread. Should the while not be a for loop?
Do you see any other problems with the way the code is written?
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Clear Logic |
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mbradley
Joined: 11 Jul 2009
Posts: 118
Location: California, USA
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| Posted: Fri Feb 05, 2010 12:00 am |
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Some times we do not see things when they are in front of us, I can only assume PCM was looking for a pointer as to what we should be looking for.
Case in point, this code drove me nuts looking for my error:
if (fltMode == MODE_FAA) { procFAA(); )
even though it was in front of me, I didnt see it, so imagine that line mixed with other code.
I understand you had a question, but you did not post what you thought was wrong with it.
I am not trying to stir things up, I like it here. sometimes we just need more information.
_________________
Michael Bradley
www.mculabs.com
Open Drivers and Projects |
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Gavin Pinto
Joined: 18 Oct 2009
Posts: 27
Location: Australia
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| Posted: Fri Feb 05, 2010 12:17 am |
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| mbradley wrote: | Some times we do not see things when they are in front of us, I can only assume PCM was looking for a pointer as to what we should be looking for.
Case in point, this code drove me nuts looking for my error:
if (fltMode == MODE_FAA) { procFAA(); )
even though it was in front of me, I didnt see it, so imagine that line mixed with other code.
I understand you had a question, but you did not post what you thought was wrong with it.
I am not trying to stir things up, I like it here. sometimes we just need more information. |
Well the simple code I posted above has more errors. Since it is meant to be a tutorial I hope someone helps verify what I found.
_________________
Clear Logic
Last edited by Gavin Pinto on Fri Feb 05, 2010 3:14 am; edited 1 time in total |
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Gavin Pinto
Joined: 18 Oct 2009
Posts: 27
Location: Australia
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| Posted: Fri Feb 05, 2010 2:48 am |
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| mbradley wrote: | Some times we do not see things when they are in front of us, I can only assume PCM was looking for a pointer as to what we should be looking for.
Case in point, this code drove me nuts looking for my error:
if (fltMode == MODE_FAA) { procFAA(); )
I am not trying to stir things up, I like it here. sometimes we just need more information. |
The wrong brace (closing bracket) you used is easy to spot from miles away. We all make these mistakes. So I am not talking about that. Basically I am looking for good examples to cut and paste that test the new compiler features.
Also interested what they do at the lower level. Still waiting for responses to what other problems you notice with the code I posted.
_________________
Clear Logic
Last edited by Gavin Pinto on Fri Feb 05, 2010 3:07 am; edited 1 time in total |
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Wayne_
Joined: 10 Oct 2007
Posts: 681
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| Re: Errors in the CCS Webpage code |
| Posted: Fri Feb 05, 2010 3:07 am |
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| Gavin Pinto wrote: | I believe there are a few errors in code below. So please verify my findings so I will send feedback to CCS official support later to correct the oversight.
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If you had said what your findings were then you may have got some feedback. As it stands it looks like you are asking us to do your home work or for some reason are testing us!
e.g. Here is some code I have written, it has errors, can you find them ?
I didn't actually understand what you were doing until I visited that link. Your explanation is not very good. |
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Gavin Pinto
Joined: 18 Oct 2009
Posts: 27
Location: Australia
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| Re: Errors in the CCS Webpage code |
| Posted: Fri Feb 05, 2010 3:10 am |
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| Wayne_ wrote: | | Gavin Pinto wrote: | I believe there are a few errors in code below. So please verify my findings so I will send feedback to CCS official support later to correct the oversight.
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If you had said what your findings were then you may have got some feedback. As it stands it looks like you are asking us to do your home work or for some reason are testing us!
e.g. Here is some code I have written, it has errors, can you find them ?
I didn't actually understand what you were doing until I visited that link. Your explanation is not very good. |
No not testing you. I already tried to compile the code and came up with errors. Just wish you could also test to verify my findings. That's all.
and if you are interested in the features the code tries to demonstrate.
if not interested than ignore this post.
_________________
Clear Logic |
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Wayne_
Joined: 10 Oct 2007
Posts: 681
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| Re: Errors in the CCS Webpage code |
| Posted: Fri Feb 05, 2010 3:14 am |
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| Gavin Pinto wrote: | | Wayne_ wrote: | | Gavin Pinto wrote: | I believe there are a few errors in code below. So please verify my findings so I will send feedback to CCS official support later to correct the oversight.
|
If you had said what your findings were then you may have got some feedback. As it stands it looks like you are asking us to do your home work or for some reason are testing us!
e.g. Here is some code I have written, it has errors, can you find them ?
I didn't actually understand what you were doing until I visited that link. Your explanation is not very good. |
No not testing you. I already tried to compile the code and came up with errors. Just wish you could also test to verify my findings. That's all. |
We still don't know what your findings are other than "it came up with errors", you also stated that compilation wasn't required yet you compiled it and found errors. Different versions of compiler may return different errors so PCMs post is relevant.
Later you post that you thought the while should be a for and looking at it this seems to be correct but you also state there are other errors. What were they and are they relevant to your compiler version ? |
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Gavin Pinto
Joined: 18 Oct 2009
Posts: 27
Location: Australia
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| Re: Errors in the CCS Webpage code |
| Posted: Sun Feb 07, 2010 9:55 pm |
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| Quote: |
Later you post that you thought the while should be a for and looking at it this seems to be correct but you also state there are other errors. What were they and are they relevant to your compiler version ? |
Well
i< (sizeof(strings) / sizeof(constant char*)) is incorrect
_________________
Clear Logic |
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Wayne_
Joined: 10 Oct 2007
Posts: 681
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| Posted: Mon Feb 08, 2010 3:12 am |
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I would say the line is correct but it does not compile in my version of the compiler:-
CCS PCM C Compiler, Version 4.058
If I remove the const type from the lilne it compiles OK.
for (i = 0; i < (sizeof(strings) / sizeof(char *)); i++)
I don't know if it works correctly, not setup to test it. the size of a const char * may be different to a char *. I doubt it though as the .lst file shows the correct value of 4.
.................... i = sizeof(strings) / sizeof(char *);
*
00AB: MOVLW 04
00AC: MOVWF 27 |
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Gavin Pinto
Joined: 18 Oct 2009
Posts: 27
Location: Australia
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| Posted: Mon Feb 08, 2010 5:07 pm |
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| Wayne_ wrote: | I would say the line is correct but it does not compile in my version of the compiler:-
CCS PCM C Compiler, Version 4.058
If I remove the const type from the lilne it compiles OK.
for (i = 0; i < (sizeof(strings) / sizeof(char *)); i++)
I don't know if it works correctly, not setup to test it. the size of a const char * may be different to a char *. I doubt it though as the .lst file shows the correct value of 4.
.................... i = sizeof(strings) / sizeof(char *);
*
00AB: MOVLW 04
00AC: MOVWF 27 |
Firstly sizeof(char *) evaluates to 2
sizeof(strings) evaluates to 4
4/2=2
sizeof(ptr) evaluates to 4 if pointer is declared as char rom *ptr;
now 4/4 =1
char rom *ptr;
rom char * ptr; //ptr is stored in RAM, is a pointer to ROM
rom char rom * ptr; //ptr is stored in RAM, is a pointer to ROM
char rom * ptr; //ptr is stored in RAM, is a pointer to ROM
now compare to following
const char* ptr1; // Ptr1 is a pointer to read-only RAM and is 2 bytes
char const* ptr1; //Ptr1 is a pointer to read-only RAM and is 2 bytes
Compiler version used 4.104 PCH
device is PIC18F8722
_________________
Clear Logic
Last edited by Gavin Pinto on Tue Feb 09, 2010 4:51 pm; edited 1 time in total |
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Wayne_
Joined: 10 Oct 2007
Posts: 681
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| Posted: Tue Feb 09, 2010 3:23 am |
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Well, my compiler works differently to yours.
Sizeof(strings) = 8; // This is a pointer array. Each index contains a pointer to the string which is sizeof(char *) 2 bytes. so strings is 8 bytes in size.
sizeof(char *) = 2;
From the lst file
| Code: |
.................... a = sizeof(strings);
*
00AB: MOVLW 08
00AC: MOVWF 27
.................... b = sizeof(char *);
00AD: MOVLW 02
00AE: MOVWF 28
.................... i = sizeof(strings) / sizeof(char *);
00AF: MOVLW 04
00B0: MOVWF 29
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The fomula
i = sizeof(strings) / sizeof(char *); returns 4 which is the number of null terminated strings in the pointer array strings. Which is correct.
Show me your .lst code where
"sizeof(strings) evaluates to 4"
Or did you work it out some other way ? |
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