CuRT : Compat Unicellular Real-Time operating system.

Features

• Preemptive Multi-threading
• Priority-base Round-Robin Scheduling
• Thread Management
• Semaphore Management Support
• IPC: mailbox, message queue

Licensing

Revised BSD License. Please check the file LICENSE.txt for details.

Supported Hardware

• Marvell/Intel Xscale PXA25x platforms
• Emulated ARM PXA environment by QEMU

Building and Testing

• ARM Toolchain from CodeSourcery: Sourcery G++
• Download "arm-linux" toolchain and set up the required path.
• Prepare QEMU as ARM system emulator (version >= 0.9.1)
• Execute the following commands to build CuRT and sample application

  $ make && cd app/shell

• Install built CuRT image into NAND flash:

  $ ./prepare-flash

• Launch CuRT via QEMU:

  $ ./run-connex

• Type "help" to get information from shell

  $ help

Internals

• Thread state:

  • RUNNING
  • READY
  • EVENT_WAIT
  • BLOCK
  • DELAY
  • TERMINATE

• Scheduling policy The scheduler is called in the following two cases:

  • SCHED_TIME_EXPIRE : when thread's time_quantum value is 0.
  • SCHED_THREAD_REQUEST : Request the execution for higher priority thread.

defined in prio_exist_flag

 		----------------------------------------------------------------
 		|0|1|0|0|0|0|0|0|0|0|1|0|0|0|0|0|0|0|0|0|1|0|0|0|0|0|0|0|0|0|0|1|
 		----------------------------------------------------------------
    		|                 |                   |                     |
    		|                 |                   |                     |
		ready_list[1]     ready_list[11]    ready_list[21]         ready_list[31]
                                                                      |
                                                                  Idle thread