/* 	This assembly file contains various support routines 
	that are used throughout the libraries.

	The Run Time Library for the C Language.

	Gordon A. Sterling	(617) 461 - 3076
	DSP Development Tools Engineering

	Created on 1/2/93
	Updated on 3/95 by AS - separated functions

*/

#include "lib_glob.h"
#include "str_glob.h"

.SEGMENT/CODE 	Code_Space_Name;
.FILE		RTL_FILENAME;

/* This routine determines the length of an input string that is located
   in program memory (___lib_strlenpm).							

   Calling Parameters
	R2 --> Input String
	dm_lnt = 0

   Return Registers
	pm_ptr --> End of String (NULL)
	R0 = Length of string

   Altered Registers
	R0, R2, pm_ptr

   Cycle Count
	length of string + 5

*/

.GLOBAL		___lib_strlenpm;

/* This can get a bit confusing because there is a two iteration delay	*/
/* before the loop exits, so we need to decrement the length by two.  We*/
/* do this by incrementing the starting pointer by one, and decrementing*/
/* the ending pointer by one before the math.  There is a final 	*/
/* of the ending point so that it actually points to the NULL character	*/
/* 									*/
/* This routine does not check for NULL input pointers.  If a NULL 	*/
/* pointer is sent as input to this routine, a negative number will be	*/
/* returned for the length.  Watch out!					*/

___lib_strlenpm:R0=PASS R2, pm_ptr=R2;		/* Hold string start	*/
		DO find_pm_end UNTIL EQ;	/* Loop until NULL	*/
find_pm_end:	   IF NE R2=PASS R2, R2=PM(pm_ptr,pm_1);
		MODIFY(pm_ptr, pm_M1);		/* Back up to NULL	*/
		RTS (DB), R0=R0+1;		/* Return to Caller	*/
		R2=pm_ptr;
		R0=R2-R0, MODIFY(pm_ptr, pm_M1);/* Compute length	*/

.ENDSEG;