3 Replies Latest reply on Jul 8, 2013 5:50 AM by ki.leung

    memory mapping

    nilesh.tekale
              hello everybody, i,m using psoc3 and i would like to know how can i reduce the memory used by xdata, const, code memory for my project. in my .map file START STOP LENGTH ALIGN RELOC MEMORY CLASS SEGMENT NAME ========================================================================= 001688H 001B6DH 0004E6H BYTE UNIT CODE ?PR?_SEND_READER_CARD?MAIN 001B6EH 001F3CH 0003CFH BYTE UNIT CODE ?PR?_COMMAND_RECIEVED?MAIN actually SEND_READER_CARD is a function i'm calling from main. It has only 2 ints & a string of 30 chars of his own. if to reduce length what should i do? Is there any another trick ?   
        • 1. Re: memory mapping
          user_1377889

          Have a look at optimization techniques for PSoC3 here

             

          Bob

          • 2. Re: memory mapping
            user_14586677

            Some stuff I used on another architecture, most will work for PSOC 3, but

               

            lists like this are compiler dependent, so try them out in a sample build.

               

             

               

             

               
                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) -   
               
                    
               
                                 This                        void dosomething ( void  ) {   
               
                    
               
                                                                                 for ( unsigned char I = 0;…..   
               
                                                                 }   
               
                    
               
                                 Not This               void dosomething ( void  ) {   
               
                    
               
                                                                 Unsigned char I = 0;   
               
                    
               
                                                                                 for ( I = 0;…..   
               
                                                                 }   
               
                    
               
                Some help -   
               
                    
                   
                    
                   
                    
                   
                    
               
                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.   
               
                    
               

             

               

             

               

            Regards, Dana.

            • 3. Re: memory mapping
              ki.leung

               you can also go to KEIL web site and read their application notes for 8051 which is the same CPU for PSoC3.