1``` 2. 3├── arch --- Code of the kernel instruction architecture layer 4│ ├── arm --- ARM32 architecture 5│ │ ├── arm9 --- ARM9 architecture 6│ │ │ └── gcc --- Implementation of the GCC toolchain 7│ │ ├── cortex-m3 --- Cortex-m3 architecture 8│ │ │ └── keil --- Implementation of the keil toolchain 9│ │ ├── cortex-m33 --- Cortex-m33 architecture 10│ │ │ │── gcc --- Implementation of the GCC toolchain 11│ │ │ │ │── NTZ --- Cortex-m33 Non-TrustZone architecture 12│ │ │ │ └── TZ --- Cortex-m33 TrustZone architecture 13│ │ │ └── iar --- Implementation of the IAR toolchain 14│ │ │ │── NTZ --- Cortex-m33 Non-TrustZone architecture 15│ │ │ └── TZ --- Cortex-m33 TrustZone architecture 16│ │ └── cortex-m4 --- Cortex-m4 architecture 17│ │ │ │── gcc --- Implementation of the GCC toolchain 18│ │ │ └── iar --- Implementation of the IAR toolchain 19│ │ └── cortex-m7 --- Cortex-m7 architecture 20│ │ │── gcc --- Implementation of the GCC toolchain 21│ │ └── iar --- Implementation of the IAR toolchain 22│ ├── csky --- csky architecture 23│ │ └── v2 --- csky v2 architecture 24│ │ └── gcc --- Implementation of the GCC toolchain 25│ ├── xtensa --- xtensa architecture 26│ │ └── lx6 --- xtensa lx6 architecture 27│ │ └── gcc --- Implementation of the GCC toolchain 28│ ├── risc-v --- Risc-v architecture 29│ │ ├── nuclei --- Nuclei architecture 30│ │ │ └── gcc --- Implementation of the GCC toolchain 31│ │ └── riscv32 --- Riscv32 architecture 32│ │ └── gcc --- Implementation of the GCC toolchain 33│ └── include 34│ ├── los_arch.h --- Arch initialization 35│ ├── los_atomic.h --- Atomic operations 36│ ├── los_context.h --- Context switch 37│ ├── los_interrupt.h --- Interrupts 38│ ├── los_mpu.h --- Memory protection unit operations 39│ └── los_timer.h --- Timer operations 40├── components --- Components available for porting and header files exposed externally 41│ ├── backtrace --- Backtrace support 42│ ├── cppsupport --- C++ support 43│ ├── cpup --- CPU percent (CPUP) 44│ ├── dynlink --- Dynamic loading and linking 45│ ├── exchook --- Exception hooks 46│ ├── fs --- File systems 47│ ├── lmk --- Low memory killer functions 48│ ├── lms --- Lite memory sanitizer functions 49│ ├── net --- Networking functions 50│ ├── power --- Power management 51│ ├── security --- Security isolation 52│ ├── shell --- Shell function 53│ ├── signal --- Signal support 54│ ├── fs --- File systems 55│ └── trace --- Trace tool 56├── drivers --- driver Kconfig 57├── kal --- Kernel Abstraction Layer, APIs exposed externally, including CMSIS APIs and part of POSIX APIs 58│ ├── cmsis --- CMSIS 59│ └── posix --- POSIX 60├── kernel --- Code for defining the minimum kernel function set 61│ ├── include 62│ │ ├── los_config.h --- Configuration parameters 63│ │ ├── los_event.h --- Events management 64│ │ ├── los_membox.h --- Membox management 65│ │ ├── los_memory.h --- Heap memory management 66│ │ ├── los_mux.h --- Mutex 67│ │ ├── los_queue.h --- Queue 68│ │ ├── los_sched.h --- Scheduler 69│ │ ├── los_sem.h --- Semaphores 70│ │ ├── los_sortlink.h --- Sort link 71│ │ ├── los_swtmr.h --- Timer 72│ │ ├── los_task.h --- Tasks 73│ │ └── los_tick.h --- Tick 74│ └── src 75├── testsuites --- Kernel testsuites 76├── tools --- Kernel tools 77└── utils 78 ├── internal 79 ├── BUILD.gn --- Gn build config file 80 ├── los_compiler.h --- Compiler configuration 81 ├── los_debug.c --- Debugging facilities 82 ├── los_debug.h 83 ├── los_error.c --- Errors codes and definitions 84 ├── los_error.h 85 ├── los_hook.c --- Hook function facilities 86 ├── los_hook.h 87 ├── los_list.h --- Doubly linked list 88 └── los_reg.h --- Register macros 89``` 90 91