nes-proj/cpu
Andre Guedes e28f400e0c x86: Introduce interrupt.h
This patch introduces the interrupt.h header file which provides some
helper macros to set a interrupt handler and disable/enable maskable
hardware interrupts.

Since there is no easy way to write an Interrupt Service Routines
(ISR) in C (for further information on this, see [1]), we introduce
the SET_INTERRUPT_HANDLER helper macro.

The macro does two things:
1) Defines an assembly trampolin to a C function that will, indeed,
   handle the interrupt.
2) Sets the corresponding interrupt gate descriptor in IDT.

The macro usage is pretty straightforward. The macro is defined as
SET_INTERRUPT_HANDLER(num, has_error_code, handler) where:
@num:             Interrupt number (0-255)
@has_error_code:  0 if processor doesn't push error code onto the
                  stack. Otherwise, set this argument to 1.
@handler:         Pointer to function that should be called once the
                  interrupt is raised. In case has_error_code == 0
                  the function prototype should be the following:
                  void handler(void)
                  Otherwise, it should be:
                  void handler(struct interrupt_context context)

For instance, let's say we want to set a handler for a device interrupt
(for example, interrupt number 101). Remember, hardware interrupts don't
have error code. So we should have something like this:

void interrupt_handler(void)
{
        /* Handling code here */
}

void my_device_init(void)
{
        ...

        SET_INTERRUPT_HANDLER(101, 0, interrupt_handler);

        ...
}

Now, let's say we want to set an interrupt handler for Page Fault
(interrupt number 14). Some exceptions, such as Page Fault, pushes an
error code onto the stack and may require registers values in order
to be properly be handled. Thus, the code should look like this:

void pagefault_handler(struct interrupt_context context)
{
        /* Handling code here */
}

void init_memory(void)
{
        ...

        SET_INTERRUPT_HANDLER(14, 1, pagefault_handler);

        ...
}

For further information about exceptions and error code, refer to Intel
Combined Manual, Vol. 3, Sections 6.3 and 6.13.

Finally, we don't define any API to unregister interrupt handlers since
we believe that it wouldn't be useful at all, at least at this moment.
Considering Contiki's context, interrupt handler registration is pretty
"static" and defined at compile-time by platform code (or the device
drivers used by the platform).

[1] http://wiki.osdev.org/Interrupt_Service_Routines
2015-12-21 08:06:14 -02:00
..
6502 Removed CC_FASTCALL. 2015-11-01 18:10:17 +01:00
arm Merge pull request #1344 from tsparber/fix-doxygen 2015-11-30 22:07:15 +01:00
avr Merge pull request #1344 from tsparber/fix-doxygen 2015-11-30 22:07:15 +01:00
cc26xx-cc13xx Merge pull request #1133 from bkozak-scanimetrics/cc-gcc 2015-12-05 00:39:59 +01:00
cc253x Removed CC_FASTCALL. 2015-11-01 18:10:17 +01:00
cc2430 Removed CC_FASTCALL. 2015-11-01 18:10:17 +01:00
cc2538 Implement generic Newlib syscalls 2015-12-16 19:50:49 +01:00
mc1322x Merge pull request #1344 from tsparber/fix-doxygen 2015-11-30 22:07:15 +01:00
msp430 Adding definitions required for TSCH to the sky and z1 platforms 2015-12-04 15:21:53 +01:00
native Merge pull request #1293 from simonduq/pr/fix-warnings 2015-11-10 08:49:11 +01:00
pic32 [cpu/pic32] Removed excess end group 2014-11-10 23:53:33 +01:00
rl78 The -pedantic and -stdc flags trigger a few too many warnings 2015-10-20 10:11:35 +02:00
stm32w108 Merge pull request #1344 from tsparber/fix-doxygen 2015-11-30 22:07:15 +01:00
x86 x86: Introduce interrupt.h 2015-12-21 08:06:14 -02:00