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diff --git a/doc/coding_rules.txt b/doc/coding_rules.txt new file mode 100644 index 0000000..e5c11f0 --- /dev/null +++ b/doc/coding_rules.txt @@ -0,0 +1,120 @@ +CODING STYLE FOR THIS PROJECT +============================= + +In order to have a consistent codebase, there are the following rules on +writing code in C (and assembly). For the most part they are similar to the +Linux kernel coding rules by Torvalds. + +PROGRAM LOGIC +------------- +I expect a certain level of common sense from people so I won't mention the +super-basic stuff. But I would like to point out a few thing I WON'T accept +(unless there is a valid reason and an explanation of why). First, I believe +that code has to be aesthetically pleasing to watch and with a clear logic +flow so: + + - Avoid deeply nested code and recursive black magic + + - No special cases: generally the code of a function should behave the + same with any argument. Avoid horrible exceptions for magic values + + - No extreme modularization: do not write code that is extremely + encapsulated with dozens of helper functions to control every signal + that runs through the damn motherboard + +EDITOR (SPACES > TABS) +---------------------- +You can use your favourite editor but spaces are better than tabs, no +discussion. For this project every source file must have an indent of 4 +spaces. Since 80 characters is the standard terminal width, the code has to be +hard wrapped at 80, 78 or 72 characters. Also there shouldn't be any markup on +the source code for your editor, not even in the comments; just the code. + + - use spaces, 1 indent - 4 spaces + - hard wrap at 80 / 78 / 72 characters + - no markup for folds or any other editor specific feature + + +C CODE INDENT AND BRACES +------------------------ +I personally prefer the K&R coding style because it was used in 'The C +Programming Language' book from Dennis Ritchie which is the 'standard' for +learning C. But I also like Linus' kernel coding rules, so sometimes I might +use some of his rules. Anyway, you can look them up if you want to or just +look at the following example that sums most of the important stuff. + + - K&R braces and function prototypes + - snake_case for variables and function names + - pointer asterisk in front of the variable ( ex: int *p; ) + +Here's a short example that uses most of the stuff: + + #include <stdio.h> + #include <stdlib.h> + + #define MY_DEVICE_MEMORY_ADDR 0x5020 + + #define MY_DEVICE_FLAG_RDY 1 + #define MY_DEVICE_FLAG_ERR 2 + + // same for unions + struct my_device + { + volatile uint8_t buffer; + volatile uint8_t flags; + } *_my_dev = (struct my_device *) MY_DEVICE_MEMORY_ADDR; + + + int my_device_write(uint8_t *data, size_t size); + + /* This is the main function + * and this is a multiline comment to explain something if needed + */ + int main(int argc, char *argv[]) + { + int i; + int j = 0; + uint8_t data[2] = { 0xFF, 0xAB }; + const char *string = "My magic string"; + + while (j < 100) { + j++; + } + + printf("%s\n", string); + + if (some_condition) { + // inline comment + } else { + my_device_write(data, 2); + } + + switch (i) { + case 0: + some_function(); + break; + + case 1: + // ... + break; + + default: + // ... + } + } + + int my_device_write(uint8_t *data, size_t size) + { + int i; + + for (i = 0; i < size; i++) { + _my_dev.buffer = data; + while (!(_my_dev.flags & (1<<MY_DEVICE_FLAG_RDY))); + + if (_my_dev.flags & (1<<MY_DEVICE_FLAG_ERR)) { + return -1; + } + } + + return i; + } |