/*
	   This C language subroutine manipulates semaphores 
	   used on the Z3 processor.

	   The Run Time Library for the C Language.

	   Alexander Soto
	   DSP Development Tools Engineering

	   Created on 6/4/92  by GAS
	   Updated on 8/94  by AS

	   #include <21060.h>			<Header>
	   int test_and_set_semaphore(void *semaphore, int test_value,
			     int set_value, int timeout);
		returns (-1 for timeout, 0 for passed, 1 for test failure)


	   int set_semaphore(void *semaphore, int set_value, \
			     int timeout);
		returns (-1 for timeout, 0 for passed)
	  
*/

#include "lib_glob.h"
#include "060_glob.h"

.SEGMENT/CODE	Code_Space_Name;
.FILE 		RTL_FILENAME;

.GLOBAL	    	_test_and_set_semaphore, _set_semaphore;


_test_and_set_semaphore: JUMP (PC, sem_core) (DB);
		reads(R2,1);			/* Read timeout value		*/
		R1=1;				/* Flag set to test		*/

_set_semaphore: R2=R12;				/* Read timeout value		*/
		R1=R1-R1, R12=R8;

sem_core:	R0=-2;				/* Decrement value is 2 b'cse	*/
						/* there are 2 cycles in loop.	*/
		R2=R2+R0, dm_ptr=R4;		/* Read semaphore address	*/
		IF LT R2=-R0;			/* If timeout <= 0, set to two	*/
		BIT SET MODE2 0x00000040;	/* Prepare for bus lock		*/

		DO timeout_check UNTIL LE;
		  IF NE R2=R2+R0;		/* Decrement time out		*/
timeout_check:	  IF BM R0=R0-R0, R2=dm_1;	/* We have control clear ret	*/

		IF NOT BM JUMP (PC, restore_state) (DB); /* Timed out		*/
		IF NOT BM R0=dm_M1;
		R1=PASS R1, FETCH_RETURN	/* Should I test value?		*/
		
		BIT CLR MODE1 0x00001000;	/* Shut off interrupts for now	*/
		R4=DM(dm_0,dm_ptr);		/* Get semaphore		*/
		IF NE COMP(R4,R8);		/* Test sem==test val, R0=1	*/
		IF NE R0=R2;			/* sem != test, R0=1		*/

set_value:	IF EQ DM(dm_0,dm_ptr)=R12; 	/* Set semaphor	if sem==test val*/
		BIT SET MODE1 0x00001000;	/* Restart interrupts		*/

restore_state:  RETURN (DB);
		BIT CLR MODE2 0x00000040;	/* Relinquish bus mastership	*/
		RFRAME;
		
.ENDSEG;