Hydrogen/Core51 is a Keil C51 None-Preemptive OS. CORE written by Pure C (well..almost Pure, has 10 lines inline ASM).
CORE minimal resource
**Size about 2.3~5K ROM, 20+ Byte RAM. it is depends modules your chosen.
**CORE also TAKE TIMER0 to tick for real-timing, and need xdata for HEAP
CORE Support
**dynamic Create/Terminate Thread(TASK)
**Synchronize Object (Event / Semaphore / Critical Section), Thread(TASK) Naturally GIVES UP CPU by WaitFor these Synchronize Object...