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Hi all,
I'm looking for some memory optimization.
at one stage I build my project and it shows my memory mapping as
Program Size: data=22.0 xdata=3506 const=5803 code=16419
ERROR: L107: ADDRESS SPACE OVERFLOW CONST ?CO?MAIN 0000BEH
ERROR: L120: CONTENT BELONGS TO ERRONEOUS SEGMENT ?CO?MAIN
Now if I remove few lines from my code it reduces 18 BYTES as
Program Size: data=22.0 xdata=3506 const=5803 code=16401
Flash used: 22204 of 32768 bytes (67.8 %).
SRAM used: 3506 of 4096 bytes (85.6 %).
It means no change in memory other than code memory so why the error is overflow from const memory.
and if we consider about code memory then yet 10546 BYTES are free to use.
Is there any relation with no. of components used in topdesign and the flash memory we can use.
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PSoC 3
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Beforfe Imagecraft Pro was released I experiened a 40% code reduction
using HiTech, which is no longer offered/supported (other than other
users, psocdeveloper.com).
I did extensive code reduction on a 29466 to fit my application, and the
below is what I did to achieve this.
These helped me in a similar experience -
1 - If any float math minimize the number of lines you do divides, if possible convert
to multiplies. Convert float to integer math where possible. Pay attention to factoring
of expressions, possible operation reduction, hence code reduction may result.
2 - Lines with function calls, minimize f(g()) compound typed expressions.
3 - Make sure you only use a variable type no larger than needed.
4 - Use unsigned variables wherever possible.
5 - Watchout for structures with mixed const and ram pointers within them,
some compilers choke on this.
6 - If you are heavy on Flash, light on RAM use, convert routines to RAM based
wherever possible.
7 - Try test cases of looping structures, to see what affects code size generation.
8 - Examine .lst file for code that looks wacky in bytes used, understand what
compiler did, and consider rewrite.
9 - Use inline ASM where .lst file C generation looks excessive.
10 - Look at module reuse, sharing, dual purpose, to eliminate # modules
needed, like counters/timers....Also look at data sheets of modules that could
serve function needed, and compare ROM/RAM requirements needed. Optimize
global HW, like clocks VC1/2/3/Sleep, to eliminate need for other timer/counters.
Use register routing control to "share" module from one task to another, one pin
to another.
11 - Extended library, functions within them are written to be perfectly general,
hence larger code size, you may be able to write one with less code needed for
your specific requirements that result in smaller code size.
12 – Look for approximations to compute transcendental functions if used.
13 - Although no longer supported by HiTech or Cypress, the HiTech Pro compiler
yielded on first try ~ 40% code reduction in my design when I first converted
to it. Then the prior comments yielded another 4 K later in design as I was up
against 32 K Flash limitation.
14 - Some compilers have a setting to optimize code size or speed, the latter
prone to larger code size. Also look at compiler vendors web site for ap notes
and suggestions on optimization, compilers from different vendors behave and
optimize differently.
15 - const data, strings, etc.., look for ability to reuse common string mnemonics,
text.
16 - Pointer usage can lessen code size, see url's below. Look for function calls
passing longs as value vs pointer, convert to latter. Compiler has to copy all these,
if not referenced. Do not pass longs or floats as values, keep always in mind native machine size.
17 - Most compilers will optimize when indexes, pointers, a power of 2, or divides,
divide becomes a shift.
18 - Look at how linker distributed code and data segments, sometimes you can discover
a poor decision by linker and force code/data into certain psects using pragma constructs,
thereby minimizing wasted ROM space.
19 – When you debug generally you want to turn off optimization, as compiler/linker will
remove code and make jumps that do not make “sense” but are the result of optimization.
When you are up to Flash boundary you may not be able to turn it off, otherwise
application will not load. Keep this in mind, that your debug strategy may have to change.
I also found if using ICE Cube that debugger may no longer report “watch” variables, this
occurred at ~ 31.5K bytes. In either case you may want to comment out large code sections
to effectively debug.
20 – f() calls take overhead, if you only call a f() once you might eliminate it as a f() call and
place code inline.
21 – Look for f() opportunities, wherever you are coding and repeating similar operations.
This is obvious, but sometimes missed.
22 – Check compiler on macros, to see if they are being optimized or just being used inline
using more code space vs a f() call solution.
23 – Examine compiler/linker parameter control. For example in HiTech there is the AUTOBANK
setting that controls where local variables are stored, in my case setting to 1 lowered code size by
~ 250 bytes. READ the MANUAL !
24 – Use inline variable declarations, vs pre declaration (compiler dependent) -
Note note supported in Imagcraft
This void dosomething ( void ) {
for ( unsigned char I = 0;…..
}
Not This void dosomething ( void ) {
Unsigned char I = 0;
for ( I = 0;…..
}
Some help -
http://www.codeproject.com/Articles/6154/Writing-Efficient-C-and-C-Code-Optimization
http://www.eventhelix.com/realtimemantra/basics/optimizingcandcppcode.htm
http://www.azillionmonkeys.com/qed/optimize.html
By using these techniques I was able to regain ~ 4K Bytes of code space in a 32K design, which
I promptly then used up again 😞
Regards, Dana.
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I think the issue is with the Keil compiler for PSoC3 not PSoC1, but some of your suggestions is still valid.
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I didn't have the spec on hand, but that seems to be at the lower end of the flash address which seems to be around the interupt vector area.
May be upload your code here so people can check as well
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Constant data (such as string constants) go to flash, like code does. So if flash memory size is not sufficient to place both, it seems to report that the const data cannot be placed. But either reducing the code size or the data size will help you here.
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0BEH is around the end of the jump vector. And I think the default starting address of code is at 100h.
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My error on Imagecraft/HiTech post, however many of the suggestions apply.
Additionally try simple tests to see what Keil will do in terms of code density.
If you are up against FLASH size barrier you will be surprised how simple
changes to code can produce modest, but importent savings in code size.
Especially using pointers for non native variable sizes.
Regards, Dana.
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Upload your project, so people can check. That is the faster way to solve your issue.
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Hello H L,
I have attached my project here. and my application is not completed yet, so lot much is there to add.
But I wish to know meaning of your statement in deep [0BEH is around the end of the jump vector. And I think the default starting address of code is at 100h. ]. Please tell me where I can get its detail description?
and Thanks to all for replying.
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I tried again to upload
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My project is not uploading. It is in .zip
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When attaching files don't use Chrome. Use IE or Firefox.
Regarding your question: you can look at the Technical Reference Manual (TRM), there shiould be a memory map in there. And there you can see which stuff is in certain memory locations. But I guess it doesn't really matter, since the linker just complains that the code is too large.
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I am trying it in firefox
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Try IE, it should work.
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I tried a compile, but am getting error due to bootloader dependancy, so
cannot get your orginal error issue. I did this in 2.2 as I noticed you are
not using Creator 3.0.
Looking over code I see some loing usage, but not using pointers to them.
Both in f() calls and inline code. 8051 longs are not native, so extra code is
used to handle them. Moving/copying/stack push reduction greatly aided by
use of pointers on longs.
Regards, Dana.