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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)
Code _can_ be self-documenting. It's a question of complexity compared to the expected knowledge of the reader.
A trivial example is a "hello world" app. If that isn't self-documenting, the reader should switch to doing something else.
The big problem is always to figure out what a suitable level of documentation is, since the world is never black _or_ white.
The big problem is always to figure out what a suitable level of documentation is, since the world is never black _or_ white. agree, to some extent; however, I would never complain that any code is too commented.
A trivial example is a "hello world" app. If that isn't self-documenting, the reader should switch to doing something else. This is the road to perdition, where does "self-documenting" end?. "hello world" is NOT "self-documenting"; however it is so simple that the lack of documentation does not limit the understanmdin of the process.
So, instead of the blasted untrue "self-documenting" can we agree on "so simple that documenting not needed"
Using that instead of the blasted "self-documenting" the OPs argument "commrnts not needed" falls flat.
Erik
I would never complain that any code is too commented.
I would. As the first of the ancient pharmacologists noted, dosage is what makes a poison. People will take sayings like "you can never have too much comment" literally, and you end up with a code/comment ratio of 1 percent or less --- one line of code per screenful of source. If you can't see more than three lines of actual code at a glance on a full-screen editor, then yes, that means the code is over-commented.