What do you mean, PMP ?

Seb

2011/5/9 funlw65(Vasi) <[email protected]>

> Can you give to PMP a try? The next version will be awesome!
>
> Vasi
>
> On May 9, 12:55 pm, Sebastien Lelong <[email protected]>
> wrote:
> > Hi guys,
> >
> > Minix is a big lib, minix can't compile without -no-variable-reuse. Since
> > compiler can't handle this amount of code (it takes hours to compile,
> maybe
> > days, actually I didn't wait for complete compilation, it's just too
> > long...), I tried to reuse variable myself, within the code. Following is
> a
> > blinded example with fat32.jal library, another big one.
> >
> > First, results before optimization:
> >
> > jallib compile -no-variable-reuse sample/18f4550_fat32_sd_card.jal
> > jal 2.4o (compiled May  8 2011)
> > generating p-code
> > 6309 tokens, 357042 chars; 8703 lines; 16 files
> > generating PIC code pass 1
> > generating PIC code pass 2
> > writing result
> > Code area: 19364 of 32768 used (bytes)
> > Data area: 1542 of 1952 used
> > Software stack available: 410 bytes
> > Hardware stack depth 10 of 31
> > 0 errors, 0 warnings
> >
> > Now, let's dig one procedure, "randomly" picked:  fat32_file_entry_data.
> It
> > declares, within its body, the following variables (I just read it,
> > extracting "var ...").
> >
> > var byte sector_after_entry_location
> > var word sector_entry_number
> > var byte char_pos = 0
> > var byte number_of_entries
> > var byte step3
> > var word sector_entry_number2 = sector_entry_number * 32
> > var byte long_name_step = FAT32_FILE_NAME_SIZE - 13
> > var byte sector_step = 0
> > var byte first_char
> > var byte step3
> > var byte step
> > var byte _cluster_address[4] at fat32_file_cluster_address
> > var byte _file_size[4] at fat32_file_size
> > var byte _cluster_address[4] at fat32_file_cluster_address
> >
> > These variables are declared either at body's root, or within "for", "if"
> > block. Some can't be reuse, but, *maybe*, some can actually be reused,
> > because their content is only used within a limited, predefined timeline.
> > Let's first move all these declaration at the top of body. Compiling
> reveals
> > the following duplicates: step3, _cluster_address, and _file_size.
> Removing
> > duplicates gives the following output:
> >
> > Code area: 19424 of 32768 used (bytes)
> > Data area: 1540 of 1952 used
> >
> > Why program memory grew that way ?? I can't explain... Let's continue.
> step
> > and step3 are using within for loops, not at the same time. We can remove
> > step3 and use step instead:
> >
> > Code area: 19530 of 32768 used (bytes)
> > Data area: 1539 of 1952 used
> >
> > 19530 bytes !!! Why ? One byte RAM saved...
> > (is that about banking ?)
> >
> > Oh well... I rewrote that mail 10 times as I actually discovered the
> results
> > :) I'm stopping here, and starting to understand why my Minix lib is so
> big.
> > I indeed used a lot of "alias" in order to try to reuse variables
> > "manually", and save RAM, and it does but the amazingly growing number of
> > program bytes is quite scary...
> >
> > Cheers,
> > Seb
>
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>


-- 
Sébastien Lelong
http://www.sirloon.net
http://sirbot.org

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