// raise15.asm
//
//  This code should be the first thing called from main if
//   you want to to have interrupts work with the
//   SRV1 firmware.  It raises an IVG15 interrupt, then it
//   reenters main.  This makes the firmware code run
//   within the context of a level 15 interrupt which is the
//   the lowest priority interrupt of the BlackFin.  All other
//   interrupts can interrupt a level 15 interrupt service
//   routine.
//
//   main.c must have:
//   1)  a global defined

//         int raise15called = 0;

//   2)  The very first thing done in main() must be
//       a check of the global with a call to _raise15
//       to make sure it is only called once:
//
//	       if(raise15called == 0){
//		    raise15called = 1;
//		    _raise15();
//          }
//
//   Also,
//   makefile must have raise15.asm added to the list of ASMSRCS
//
//   srv1.x must have raise15.o(.text) added to the list of objects in
//     the .l1code section

.text;

#include <defBF537.h>

#include "config.h"
#include "asmmacros.h"

.global __raise15;

__raise15:
	P0.L = LO(EVT15);    // Point to IVG15 in Event Vector Table
	P0.H = HI(EVT15);

	P1.L = jmp_main;    // Point to start of User code
	P1.H = jmp_main;
	[P0] = P1;          // Place the address of start code in IVG15 of EVT
	r0 = 0x8000(z);     // enable irq 15 only
	sti r0;             // set mask

	raise 15;           // Invoke IVG15 interrupt
	P0.L = wait_here;
	P0.H = wait_here;
	reti = P0;          // RETI loaded with return address
	rti;                // Return from Reset Event

	wait_here :         // Wait here till IVG15 interrupt is serviced
	jump wait_here;

	jmp_main:           // IVG15 interrupt vectored here
	[--sp] = reti;      // pushing RETI allows interrupts to occur inside all main routines

	p0.l = _main;       // get location of main
	p0.h = _main;

	r0.l = end;
	r0.h = end;

	rets = r0;          // return address for main()'s RTS

	jump (p0);		    // jump to main

	end:;
	idle;
	jump end;
__raise15.end: