STM32 Links

STM32 Wiki

https://en.wikipedia.org/wiki/STM32

STM32F Cortex M0 manual

http://www.st.com/resource/en/reference_manual/dm00031936.pdf

Cortex Microcontroller Software Interface Standard (CMSIS)

https://www.arm.com/products/processors/cortex-m/cortex-microcontroller-software-interface-standard.php

GNU Binutils

GNU Assembler

https://sourceware.org/binutils/docs/as/