mprintf

simple no-float 32-bit printf

Status

Does everything I need it to. Will fix bugs as I come across them.

How to use this in an embedded project

1. Copy mprint.h and mprint.c into your project
2. In mprint.c, replace all the calls to putchar() with the appropriate one for your platform. In embedded projects, this is commonly a function that outputs data over UART.
3. Once putchar() is replaced, the #include <stdio.h> line in mprintf.c should no longer be needed. Feel free to delete it.
4. If needed, adjust the newline encoding in print_newline().
5. Done!

How to measure the size of this project

1. copy these files into an embedded project.
2. compile the project.
3. measure the size of the mprintf.o object file using size -A.
4. the total size is found from summing all relevant sections together.

Details

Compiles down to 1554 bytes on arm-none-eabi-gcc with -Os optimizations. This can be made slightly smaller depending on which functions are actually called. mprintf is about 450 lines of code (per David A. Wheeler's SLOCCount).

Max RAM usage can be controlled by changing the printf() buffer size. Shrinking the buffer saves RAM at the cost of decreasing the maximum string length printf() can handle.

Supports b, c, d, i, p, s, u, X, x, and % conversion flags, minimum field widths, and 0- +# format flags.

Designed with Cortex-M microcontrollers in mind, but there's no microcontroller-specific code in the file.

I also included testing using Greatest from https://github.com/silentbicycle/greatest. There's a number of tests that compare mprintf against the standard printf.