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Hello all, Please, could somebody tell me, why CodeWarrior doesn't using code memory space for const data (just like Keil C51 for example). I'm meaning direct access to PFLASH for const data. There are two possibilities now: 1) Cost data are placed in data RAM and its initialization values in program FLASH (so they allocates space in both XRAM and PFLASH) 2) Const data are placed in data flash (pretty well but data flash can be desired for other purposes in some applications) Best Regards, Richard Kis <mailto: |
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'Const data' question
Started by ●July 24, 2002
Reply by ●July 24, 20022002-07-24
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As you have noticed, DSP56800 tools have improved with each release.
Older versions of CodeWarrior didn't distinguish between const and initialized data, and wasted memory by allocating both X flash and X RAM. Latest CodeWarrior added new feature, which allowed allocation of const data in X Flash only. I believe primary reason for putting const data into X Flash (as appose to P Flash) is due to the nature of DSP56800/800E architecture. This is Harvard architecture, which separates program and data to optimize the performance. On the other hand, there are many developers who utilize P memory for const data (and initialized data) to save some X space. However, this could be a new compiler/linker flag, that user can set if he wants to put const data into P memory. I would recommend for you to go to Metrowerks website, and request a new feature for this product. This will be reviewed and potentially included in the future releases of CodeWarrior. Leonard N. Elevich Motorola DSPD -----Original Message----- From: Richard Kis [mailto:] Sent: Wednesday, July 24, 2002 12:10 AM To: Subject: [motoroladsp] 'Const data' question Hello all, Please, could somebody tell me, why CodeWarrior doesn't using code memory space for const data (just like Keil C51 for example). I'm meaning direct access to PFLASH for const data. There are two possibilities now: 1) Cost data are placed in data RAM and its initialization values in program FLASH (so they allocates space in both XRAM and PFLASH) 2) Const data are placed in data flash (pretty well but data flash can be desired for other purposes in some applications) Best Regards, Richard Kis <mailto: _____________________________________ Note: If you do a simple "reply" with your email client, only the author of this message will receive your answer. You need to do a "reply all" if you want your answer to be distributed to the entire group. _____________________________________ About this discussion group: To Join: To Post: To Leave: Archives: http://www.yahoogroups.com/group/motoroladsp More Groups: http://www.dsprelated.com/groups.php3 ">http://docs.yahoo.com/info/terms/ |
