libopencm3
A free/libre/open-source firmware library for various ARM Cortex-M3 microcontrollers.
LM3S
Here is a list of all modules:
[detail level 12]
 RCC DefinesDefined Constants and Types for the LM3S Reset and Clock Control
 User interrupt service routines (ISR) prototypes for LM3S series
 LM3SLibraries for TI Stellaris LM3S series
 General Purpose I/OLM3S General Purpose I/O
 RCC ControllerLM3S RCC Controller
 LM3S DefinesDefined Constants and Types for the LM3S series
 System ControlDefined Constants and Types for the LM3S System Control
 General Purpose I/O DefinesDefined Constants and Types for the LM3S General Purpose I/O
 DebuggingMacros and functions to aid in debugging
 NVIC Defineslibopencm3 Cortex Nested Vectored Interrupt Controller
 User interrupts for LM3S series
 Cortex M0/M3/M4 System InterruptsIRQ numbers -3 and -6 to -9 are reserved
 SysTick Defineslibopencm3 Defined Constants and Types for the Cortex SysTick
 Clock source selection
 User interrupt service routines (ISR) defaults for LM3S series
 NVIClibopencm3 Cortex Nested Vectored Interrupt Controller
 SysTicklibopencm3 Cortex System Tick Timer