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unsigned char sectors_per_cluster; unsigned int *pi; unsigned long *pl; pi = (unsigned int *)&raw_block[FAT_BYTES_PER_SECTOR]; partition.bytes_per_sector = *pi++; partition.sectors_per_cluster = *pi & 0xFF; pi = (unsigned int *)&raw_block[FAT_RESERVED_SECTORS]; reserved_sectors = *pi++; number_of_fats = *pi & 0xFF; pl = (unsigned long *)&raw_block[FAT_FAT_SIZE]; sectors_per_fat = *pl; partition.fat1_start_sector = partition.offset + reserved_sectors; partition.fat2_start_sector = partition.fat1_start_sector + sectors_per_fat; partition.root_dir_start_sector = partition.fat2_start_sector + sectors_per_fat; partition.last_free_chain = 0; fat_find_free_chain();} static unsigned long fat_calc_data_address(unsigned long cluster, unsigned char sector) {unsigned long offset; offset = ((cluster - 2) * partition.sectors_per_cluster); offset += partition.root_dir_start_sector; offset += sector; offset *= partition.bytes_per_sector; return offset;} static unsigned long fat_calc_chain_address(unsigned long index) {unsigned long offset; offset = partition.fat1_start_sector + (index >> 7); offset *= partition.bytes_per_sector; return offset;} void fat_load_root_directory(void) {unsigned long offset; offset = partition.root_dir_start_sector; offset *= partition.bytes_per_sector; mmc_read(offset); directory.parent_cluster = 0x00; directory.start_cluster = 0x02; directory.current_sector = 0x00; directory.current_cluster = 0x02; directory.current_direntry = (DIRENTRY *)FIRST_ENTRY_IN_ROOT;} static void fat_load_directory(unsigned long cluster, unsigned char sector, unsigned char new) {mmc_read(fat_calc_data_address(cluster, sector)); if (new) {directory.parent_cluster = directory.start_cluster; directory.start_cluster = cluster; directory.current_direntry = (DIRENTRY *)FIRST_ENTRY_IN_DIR;} directory.current_cluster = cluster; directory.current_sector = sector;} static void fat_read_next_sector_or_cluster(void) {if (directory.current_sector == (partition.sectors_per_cluster-1)) fat_load_directory(fat_next_chain(directory.current_cluster), 0, FALSE); else {directory.current_sector++; fat_load_directory(directory.current_cluster, directory.current_sector, FALSE);}} static DIRENTRY *fat_seek_directory(char *name, unsigned char find_free) {unsigned char i; DIRENTRY *p = (DIRENTRY *)START_OF_SECTOR; fat_load_directory(directory.start_cluster, 0, FALSE); i = 0; while(1) {i++; if (match_name(name, p->Name, 8)) if (p->Attribute & ATTRIB_SUBDIR) {if (!find_free) return p; else return 0;} if (!p->Name[0]) {if (!find_free) return 0; else return p;} p++; if (!(i % 0x10)) {i = 0; p = (DIRENTRY *)START_OF_SECTOR; fat_read_next_sector_or_cluster();}} return 0;} static DIRENTRY *fat_seek_file(char *name, unsigned char find_free) {unsigned char i; DIRENTRY *p = (DIRENTRY *)START_OF_SECTOR; fat_load_directory(directory.start_cluster, 0, FALSE); i = 0; while(1) {i++; if (match_name(name, p->Name, 11)) if (p->Attribute == ATTRIB_ARCHIVE) return p; if (!p->Name[0]) {if (!find_free) return 0; else return p;} p++; if (!(i % 0x10)) {i = 0; p = (DIRENTRY *)START_OF_SECTOR; fat_read_next_sector_or_cluster();}} return 0;} static unsigned long fat_find_free_chain(void) {unsigned long index = partition.last_free_chain; unsigned long *p; mmc_read(fat_calc_chain_address(index)); p = (unsigned long* )START_OF_SECTOR; p += (index & 0x7F); while(*p) {index++; p++; if (!(index % 0x80)) {mmc_read(fat_calc_chain_address(index)); p = (unsigned long* )START_OF_SECTOR;}} partition.last_free_chain = index; return index;} unsigned char fat_read_direntry(unsigned char first) {if (first) fat_load_directory(directory.start_cluster, 0, FALSE); else {if (directory.current_direntry == (DIRENTRY *)LAST_DIRENTRY) {fat_read_next_sector_or_cluster(); directory.current_direntry = (DIRENTRY *)START_OF_SECTOR;} else directory.current_direntry += 0x20; }} static unsigned long fat_next_chain(unsigned long from) {unsigned long *p; mmc_read(fat_calc_chain_address(from)); p = (unsigned long* )START_OF_SECTOR; p += (from & 0x7F); return *p;} void fat_mark_next_chain(unsigned long old, unsigned long new) {unsigned long *p; unsigned long offset; offset = fat_calc_chain_address(old); mmc_read(offset); p = (unsigned long* )START_OF_SECTOR; p += (old & 0x7F); *p = new; mmc_write(offset); offset = fat_calc_chain_address(new); mmc_read(offset); p = (unsigned long* )START_OF_SECTOR; p += (new & 0x7F); *p = 0x0FFFFFFF; mmc_write(offset);} void fat_chain_free(unsigned long index) {unsigned long *p; unsigned long temp = index; unsigned long offset; while (temp) {offset = fat_calc_chain_address(temp); mmc_read(offset); p = (unsigned long* )START_OF_SECTOR; p += (temp & 0x7F); temp = *p; *p = 0; mmc_write(offset); }} static void fat_clear_sector(unsigned long cluster, unsigned char sector) {mmc_clear(fat_calc_data_address(cluster, sector));} unsigned char fat_make_directory(char *name)
Some I wrote myself and some from somewhere else. "Did the 3rd-party code work when you got it?
Yes, but not properly.
How did you check that it was suitable for your tools and your hardware? eg, you make extensive use of int, long etc - are you sure that any assumptions about size, endianness, etc are valid?
The original code makes no such assumptions. I was told that it was platform and compiler neutral.
What have you done to isolate whether the "problems" are in the bits you've changed, or the original 3rd-party bits?
I put my bits into a separate file.
"Whet I write to a file it looks good"
Where does it "look good"? How are you checking it? What are your criteria for "looking good" - does that mean you've carefully checked in detail that it's all 100.0% correct, or you've just had a quick glance?
Yes. The call returns no error.
"when i read the file back its' f**ked up!"
That's not very descriptive, is it?
Pretty good description I though. Could also be decribed as scr**ed up or mu**ed up if you prefer.
How, exactly, is it "f**ked up"?
It doesnt do what it should. The read fails.
Where is it getting "f**ked up" - ie, are you low-level raw sector accesses working, or is it higher up the chain?
Interesting, I'll check on that one.
Can you read files that were created by other systems?
No, but the only other platform I use is Windows and I dont trust that. Do you?
"Simulators are for wimps!"
And only idiots refuse to use a tool that could help them when they're stuck! You're not getting anywhere without the simulator, so why not give it a try? Why make life difficult for yourself?
Id prefer to understand the code. Besides, how would I stimulate a memory card?
Q: Are you sure that the target is correct & working? A: Yes.
How are you sure? What testing have you done?
Erm, because the hardware guys said so. They tested it.
Simulators are for wimps!
If simulators are for wimps, then I would figure that asking for help in forums is also for wimps...
Have you done a raw dump of the written data, and manually checked that the data conforms to the expected format?
Following that logic ...
If all trees are green then it follows that all shoes are green, all cars are green and all g-strings are green.
Yes, but its complimercated and takes time!
Patience please.
"Yes, but its complimercated and takes time!"
So stop wasting your time making useless posts and get on with it!
SIR, YES SIR
id prefer to understand the code. Besides, how would I stimulate a memory card?
Can you read a file put on the memory card by a PC? Can your PC read a file you put on the memory card with a PC?
F**KUP says nothing. What do you read back Bad data? scrambled data? No data? Have you tried writing and reading a single byte? Does the file name appear on the card?
The chance that someone can just look at a few pages of code from an incomplete program and find a logic error are slim to none. AS you said none of use can run your code. the best anyone else can do is help you narrow don the problem.
Wohooo
Ive found the problem.
It was the function fat_traverse_entries that was starting at the wrong point.
No simulator used, just an understanding of the code required ;)
Anyone want some working FAT code?
Almak,
Not sure how you expected anyone to help you find the problem in fat_traverse_entries since you didn't include it in your listings.
But anyway, I guess congratulations are in order.
"Not sure how you expected anyone to help you find the problem in fat_traverse_entries since you didn't include it in your listings."
Based on that, I'd say that instead of us giving him congratulations, he give us an apology. What a waste of time!