;
; pru0_datout.asmsrc: PRU0 loop to copy XFR to GPIO out
;
; Copyright (c) 2018, Joerg Hoppe
; j_hoppe@t-online.de, www.retrocmp.com
;
; Permission is hereby granted, free of charge, to any person obtaining a
; copy of this software and associated documentation files (the "Software"),
; to deal in the Software without restriction, including without limitation
; the rights to use, copy, modify, merge, publish, distribute, sublicense,
; and/or sell copies of the Software, and to permit persons to whom the
; Software is furnished to do so, subject to the following conditions:
;
; The above copyright notice and this permission notice shall be included in
; all copies or substantial portions of the Software.
;
; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
; IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
; FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
; JOERG HOPPE BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
; IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
; CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
;
;
; 12-nov-2018  JH      entered beta phase
;
;
; Assembler function, which endlessly reads r14 from XFR area
; and copies to output pins DATOUT
; needs 15ns to loop
;
; to be declared in C as
; extern "C" {
;    void pru0_dataout(void) ;
; }
; See Compiler 2.2 Guide, Chapter 6.6

	.global	pru0_dataout

	; a 32bit parameter is received in r14
	; 10 ns delay
pru0_dataout:
	; do nothing at first
	; Device ID 14 = "other PRU"
	xin 	14,&r14,4
	mov	r30,r14
	jmp	pru0_dataout  	; never returns