Zilog ZUSBOPTS - Manual (Page 191)

UM017105-0511 Language Extensions
Zilog Developer Studio II – ZNEO™
User Manual
163
these functions and restores the machine state at the end of these functions. Also, the com-
piler uses the
iret instruction to return from these functions.
For example:
void interrupt isr_timer0(void)
{
}
or
#pragma interrupt
void isr_timer0(void)
{
}
Interrupt Vector Setup
The compiler provides an intrinsic function SET_VECTOR for interrupt vector setup.
SET_VECTOR can be used to specify the address of an interrupt handler for an interrupt
vector. Because the interrupt vectors of the ZNEO microcontroller are usually in ROM,
they cannot be modified at run time. The
SET_VECTOR function works by switching to a
special segment and placing the address of the interrupt handler in the vector table. No
executable code is generated for this statement.
The following example represents the SET_VECTOR intrinsic function prototype:
intrinsic void SET_VECTOR(int vectnum,void (*hndlr)(void));
An example of the use of SET_VECTOR is:
#include
extern void interrupt isr_timer0(void);
void main(void)
{
SET_VECTOR(TIMER0, isr_timer0);
}