| Author |
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rasega
Guest
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 Posted:
Mon Nov 28, 2005 3:42 pm Post subject:
Re: Debugging assembly |
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Thanks All,
I've RTFM and solved many problems (one of the problems was that I
didn't have the manual !!)...now searching for the complete list of the
assembler error codes ... |
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Dave Hansen
Guest
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| Posted:
Mon Nov 28, 2005 5:15 pm Post subject:
Re: Debugging assembly |
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On Mon, 28 Nov 2005 08:19:06 +0000 in comp.arch.embedded, Paul Burke
<paul@scazon.com> wrote:
[...]
| Quote: | No, I've worked with embedded systems for 25 years now, and whereas I
had to learn the assembler in the earlier days, everything is in C now.
It's still not totally portable, because of the closeness to the
hardware and its vagaries, but I'm supporting four processors at the
moment, and most of the time I couldn't care which is which.
You only really need assembler if you've underestimated the processor
capacity, or you have to support someone else's system, or you're
writing the compiler.
|
You've had a very sheltered 25 years. Most (99% or more) of the code
I write is in C or C++. But there are things you can do in assembly
that you can't do any other way, or at least, not in C. For example,
at a PPOE, I needed to write a pseudo-reset routine that would place
all processor registers in the reset state (but leave certain
peripherals untouched) before jumping to the reset vector.
Regards,
-=Dave
-=Dave
--
Change is inevitable, progress is not. |
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Paul Keinanen
Guest
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| Posted:
Tue Nov 29, 2005 1:15 am Post subject:
Re: Debugging assembly |
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On Mon, 28 Nov 2005 08:19:06 +0000, Paul Burke <paul@scazon.com>
wrote:
| Quote: | Paul Keinanen wrote:
While assembly might not be a cost effective tool for implementing
large (more than a few kilobytes) systems, understanding of
assembly/disassembly at least at a rudimentary level is essential for
working with embedded systems.
No, I've worked with embedded systems for 25 years now, and whereas I
had to learn the assembler in the earlier days, everything is in C now.
It's still not totally portable, because of the closeness to the
hardware and its vagaries, but I'm supporting four processors at the
moment, and most of the time I couldn't care which is which.
You only really need assembler if you've underestimated the processor
capacity, or you have to support someone else's system, or you're
writing the compiler.
|
I noticed in the 1970's that I could not consistently beat the RSX-11
Fortran IV+ compiler by manually translating the modules one by one
into assembly. Of course if I used e.g. global register assignment,
which the compiler did not know anything about, I could write much
better code.
Anyhow, a person working with embedded systems should have a clear
view of what each C/C++ construction will cost in terms of code space
and execution time. Writing an ISR routine entry/exit code as well as
any debugging would still require some understanding of the assembly
language for that platform.
Paul |
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rasega
Guest
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| Posted:
Tue Nov 29, 2005 5:15 pm Post subject:
Re: Debugging assembly |
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Where to find the complete list of "assembly error codes" that the
assembler reports in the .lst file ??
(error 235, error 250, ... ) |
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rasega
Guest
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| Posted:
Tue Nov 29, 2005 5:15 pm Post subject:
Re: Debugging assembly |
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| Ehmmm |
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Grant Edwards
Guest
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| Posted:
Tue Nov 29, 2005 5:16 pm Post subject:
Re: Debugging assembly |
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On 2005-11-29, rasega <richi.rasega@gmail.com> wrote:
| Quote: | Where to find the complete list of "assembly error codes" that the
assembler reports in the .lst file ??
(error 235, error 250, ... )
|
In the manual for the assembler.
--
Grant Edwards grante Yow! I'm ZIPPY the PINHEAD
at and I'm totally committed
visi.com to the festive mode. |
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rasega
Guest
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| Posted:
Wed Nov 30, 2005 9:15 am Post subject:
Re: Debugging assembly |
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Well,
it seems that the errors reported in the manual are of a form different
from what my assembler gives me back !!
In the manual I find error codes like this : Error Axxxx
What do I receive back is : Error xxx
Then I can't find the errors I'm searching for... :-( |
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Guest
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| Posted:
Wed Nov 30, 2005 5:15 pm Post subject:
Re: Debugging assembly |
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rasega wrote:
| Quote: | OH my god, I found a little table in the pcbug manual :
235 Symbol: undefined symbol
250 Data: displacement too large (normally branch)
I suppose the first (235) is due to the second (250) error,
how to correct errors like this ??
The jump can't be long as far as my code needs !!
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No, the second is more likely to be due to the first. You need to
define your symbols, chances are that you have missplet it somewhere. |
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rasega
Guest
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| Posted:
Wed Nov 30, 2005 5:15 pm Post subject:
Re: Debugging assembly |
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I'm tryin' to modify the code without using long jumps...hoping in a
good solution !!
Thank You |
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Paul Burke
Guest
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| Posted:
Wed Nov 30, 2005 5:15 pm Post subject:
Re: Debugging assembly |
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rasega wrote:
| Quote: | OH my god, I found a little table in the pcbug manual :
235 Symbol: undefined symbol
250 Data: displacement too large (normally branch)
I suppose the first (235) is due to the second (250) error,
how to correct errors like this ??
The jump can't be long as far as my code needs !!
|
Strategy 1:
Use an absolute jump. If it's a conditional jump that's causing the
problem, invert the test, and jump round the long jump which follows
immediately, e.g. (no particular assembler)
...
jz MilesAway
...
becomes
...
jnz Nearby
ljmp MilesAway
Nearby ...
Strategy 2: don't write code that uses long jumps anyway.
Paul Burke |
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rasega
Guest
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| Posted:
Wed Nov 30, 2005 5:15 pm Post subject:
Re: Debugging assembly |
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OH my god, I found a little table in the pcbug manual :
235 Symbol: undefined symbol
250 Data: displacement too large (normally branch)
I suppose the first (235) is due to the second (250) error,
how to correct errors like this ??
The jump can't be long as far as my code needs !! |
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Alex Colvin
Guest
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| Posted:
Wed Nov 30, 2005 8:54 pm Post subject:
Re: Debugging assembly |
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| Quote: | OH my god, I found a little table in the pcbug manual :
235 Symbol: undefined symbol
250 Data: displacement too large (normally branch)
I suppose the first (235) is due to the second (250) error,
how to correct errors like this ??
The jump can't be long as far as my code needs !!
|
maybe the other way - the symbol is undefined. the assembler bravely tries
to continue, using the value 0, which happens to be too far away?
--
mac the naïf |
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rasega
Guest
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| Posted:
Fri Dec 02, 2005 4:25 pm Post subject:
Re: Debugging assembly |
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Well, thank you everybody the answer was :
the labels are not accepted declared like this :
"label :"
by my assembler, than I've to do this :
"label EQU *"
Why ?? I don't know :-( |
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Jim Granville
Guest
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| Posted:
Sat Dec 03, 2005 12:39 am Post subject:
Re: Debugging assembly |
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rasega wrote:
| Quote: | Well, thank you everybody the answer was :
the labels are not accepted declared like this :
"label :"
by my assembler, than I've to do this :
"label EQU *"
Why ?? I don't know :-(
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Did you try this (in Column1) ?
Label: |
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rasega
Guest
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| Posted:
Mon Dec 05, 2005 9:15 am Post subject:
Re: Debugging assembly |
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Now I'm trying to "upload" the program on eeprom using JBUG11 but it
prompts the error :
"Argument(s) overlap excluded range"
What the problem should be ??
1) The program is bigger than available space
2) Some code try to write in protected register or memory ??
3) What else ?? |
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