= GIET-VM documentation =

[[PageOutline]]

== __A) [wiki:mapping_info Mapping_Info data structure]__ ==

== __B) [wiki:peripherals_drivers Peripherals Drivers]__ ==

== __C) [wiki:common_functions Shared kernel functions]__ ==

== __Y) [wiki:boot_loader Boot-loader]__ ==

The ''boot_init'' function makes the initialisation in two steps:
 
The first step is sequencially executed by proc[0][0][0], while other processors are in wait state:
 * Physical memory allocators initialisation : ''boot_pmem_init()''
 * Page table initialisation : ''boot_ptabs_init()''
 * Proc[0][0][0] MMU activation
 * Private vobjs initialisation : ''boot_vobjs_init()''
 * Schedulers initialisation : ''boot_schedulers init()''
 * Peripherals initialisation : ''boot_peripherals_init()''
 * Kernel & application code loading : ''boot_elf_load()''
 * Start all other processors
The second step is executed in parallel by all processors:
 * CP0_SCHED register initialisation
 * MMU Activation 
 * Status Register Initialisation (to use the GIET_VM exception handler).
 * Jump to ''kernel_init()'' 

== __W) Kernel functions__ ==

The GIET acronym stands for ''Gestionnaire Interruptions, Exceptions & Trappes''.

This section describe the kernel functions, supporting Interrupts, Exceptions and Traps (i.e. syscalls).

 === [wiki:kernel_interrupts  Interrupt Handler] ===

 === [wiki:kernel_exceptions  Exception Handler] ===

 === [wiki:kernel_syscalls  Syscall Handler] === 

 === [wiki:kernel_context Context Switch Handler] ===

== __Z) User level libraries__ ==

This section describes the user libraries :

 === [wiki:library_stdio Stdio library] ===

This library contains all system calls allowing an application
to access a protected ressource (peripheral register, or protected processor register). 
Each function in this library contains at least one SYSCALL instruction to enter the kernel mode.

=== [wiki:library_stdlib  Stdlib user library] ===

This library contains various utility functions that do not use system calls.

=== [wiki:library_mwmr  MWMR user library] ===

This library defines a communication middleware
supporting channelised communications in a multi-tasks parallel application.
This middleware does not use system calls.

=== [wiki:library_barrier Barrier user library] ===

This library contains functions used to synchronize
severals tasks in a multi-task parallel application. Most of these functions
do not use system calls.

=== [wiki:library_locks  Spin_lock user library] ===

This library contains functions used to provide
exclusive access to a shared ressource in a multi-task parallel application. 
These functions do not use system calls.

=== [wiki:library_malloc  Malloc user library] ===

This library contains functions allowing an user application
to dynamically allocate virtual memory from the application heap.
When the target architecture is clusterized (several physical banks), the heap
is physically distributed on the clusters, and there is actually on allocator per cluster.