= Kernel Utilities =

The [source:soft/giet_vm/giet_common/utils.c utils.c] and [source:soft/giet_vm/giet_common/utils.h util.h] files define useful kernel functions, that are used both by the boot_loader and by the kernel. 
They are prefixed by ''_'' to remind that they can only be executed by a processor in kernel mode.

 * They are used by the boot-loader in the ''static'' phase, to build the page tables and initialize the schedulers and the peripherals.
 * They are also used by the kernel in the ''dynamic'' phase, to handle events such as interrupts, exceptions and syscalls. 

[[PageOutline]]

 == __1) CP0 registers access functions__ ==

 === unsigned int _get_sched( void ) ===
Returns the virtual address of the scheduler stored in the SCHED register for the processor running the calling task. 

 === unsigned int _get_epc( void ) ===
Returns the value stored in the EPC register for the processor running the calling task.  

 === unsigned int _get_cr( void ) ===
Returns the value stored in the CR register for the processor running the calling task. 

 === unsigned int _get_sr( void ) ===
Returns the value stored in the SR register for the processor running the calling task. 

 === unsigned int _get_bvar( void ) ===
Returns the value stored in the BVAR register, for the processor running the calling task. 

 === unsigned int _get_procid( void ) ===
Returns the global processor identifier stored in the EBASE register for the processor running the calling task. 

 === void _set_sched( unsigned int value ) ===
Writes ''value'' in the SCHED register, for the processor running the calling task. 

 === void _set_sr( unsigned int value ) ===
Writes ''value'' in the SR register, for the processor running the calling task. 

 === void _it_disable( unsigned int* save_sr_ptr ) ===
Disables interrupts for the processor running the calling task and save the SR value at address ''save_sr_ptr''.

 === void _it_restore( unsigned int* save_sr_ptr ) ===
Writes the value pointed by ''save_sr_ptr'' into the SR register, for the processor running the calling task.



 These functions can be used to access the MIPS32 protected registers

 == __2) Physical addressing functions__ ==

 ===

 === Miscelaneous functions ===