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 -- You received this message because you are subscribed to the Google Groups "jallib" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/jallib?hl=en.
