2015-07-24 21:26:39 +02:00
|
|
|
/**************************************************************************
|
|
|
|
|
* moxart/moxart_lowputc.S
|
|
|
|
|
*
|
2015-07-29 21:52:23 +02:00
|
|
|
* Copyright (C) 2015 Gregory Nutt. All rights reserved.
|
|
|
|
|
* Author: Anton D. Kachalov <mouse@mayc.ru>
|
2015-07-24 21:26:39 +02:00
|
|
|
*
|
|
|
|
|
* Redistribution and use in source and binary forms, with or without
|
|
|
|
|
* modification, are permitted provided that the following conditions
|
|
|
|
|
* are met:
|
|
|
|
|
*
|
|
|
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
|
|
|
* notice, this list of conditions and the following disclaimer.
|
|
|
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
|
|
|
* notice, this list of conditions and the following disclaimer in
|
|
|
|
|
* the documentation and/or other materials provided with the
|
|
|
|
|
* distribution.
|
|
|
|
|
* 3. Neither the name NuttX nor the names of its contributors may be
|
|
|
|
|
* used to endorse or promote products derived from this software
|
|
|
|
|
* without specific prior written permission.
|
|
|
|
|
*
|
|
|
|
|
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
|
|
|
|
|
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
|
|
|
|
|
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
|
|
|
|
|
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
|
|
|
|
|
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
|
|
|
|
|
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
|
|
|
|
|
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
|
|
|
|
|
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
|
|
|
|
|
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
|
|
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
|
|
|
|
|
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
|
|
|
|
|
* POSSIBILITY OF SUCH DAMAGE.
|
|
|
|
|
*
|
|
|
|
|
**************************************************************************/
|
|
|
|
|
|
|
|
|
|
/**************************************************************************
|
|
|
|
|
* Included Files
|
|
|
|
|
**************************************************************************/
|
|
|
|
|
|
|
|
|
|
#include <nuttx/config.h>
|
|
|
|
|
|
|
|
|
|
#include "chip.h"
|
|
|
|
|
#include "up_arch.h"
|
|
|
|
|
#include "up_internal.h"
|
|
|
|
|
|
|
|
|
|
/**************************************************************************
|
|
|
|
|
* Pre-processor Definitions
|
|
|
|
|
**************************************************************************/
|
|
|
|
|
|
|
|
|
|
/**************************************************************************
|
|
|
|
|
* Private Types
|
|
|
|
|
**************************************************************************/
|
|
|
|
|
|
|
|
|
|
/**************************************************************************
|
|
|
|
|
* Private Function Prototypes
|
|
|
|
|
**************************************************************************/
|
|
|
|
|
|
|
|
|
|
/**************************************************************************
|
|
|
|
|
* Global Variables
|
|
|
|
|
**************************************************************************/
|
|
|
|
|
|
|
|
|
|
/**************************************************************************
|
|
|
|
|
* Private Variables
|
|
|
|
|
**************************************************************************/
|
|
|
|
|
|
|
|
|
|
/**************************************************************************
|
|
|
|
|
* Private Functions
|
|
|
|
|
**************************************************************************/
|
|
|
|
|
|
|
|
|
|
/**************************************************************************
|
|
|
|
|
* Public Functions
|
|
|
|
|
**************************************************************************/
|
|
|
|
|
|
|
|
|
|
/**************************************************************************
|
|
|
|
|
* Name: up_lowputc
|
|
|
|
|
**************************************************************************/
|
|
|
|
|
|
|
|
|
|
/* This assembly language version has the advantage that it can does not
|
|
|
|
|
* require a C stack and uses only r0-r1. Hence it can be used during
|
|
|
|
|
* early boot phases.
|
|
|
|
|
*/
|
|
|
|
|
|
|
|
|
|
.text
|
|
|
|
|
.global up_lowputc
|
|
|
|
|
.type up_lowputc, function
|
|
|
|
|
up_lowputc:
|
|
|
|
|
/* On entry, r0 holds the character to be printed */
|
|
|
|
|
|
|
|
|
|
ldr r2, =UART0_BASE /* r2=UART0 base */
|
|
|
|
|
|
|
|
|
|
/* Poll bit 0 of the UART_SSR register. When the bit
|
|
|
|
|
* is clear, the TX FIFO is no longer full
|
|
|
|
|
*/
|
|
|
|
|
|
|
|
|
|
1: ldrb r1, [r2, #UART_LSR]
|
|
|
|
|
tst r1, #UART_LSR_THRE
|
|
|
|
|
beq 1b
|
|
|
|
|
|
|
|
|
|
/* Send the character by writing it into the UART_THR
|
|
|
|
|
* register.
|
|
|
|
|
*/
|
|
|
|
|
|
|
|
|
|
strb r0, [r2, #UART_THR]
|
|
|
|
|
|
|
|
|
|
/* Wait for the tranmsit holding regiser (THR) to be
|
|
|
|
|
* emptied. This is detemined when bit 6 of the LSR
|
|
|
|
|
* is set.
|
|
|
|
|
*/
|
|
|
|
|
|
|
|
|
|
2: ldrb r1, [r2, #UART_LSR]
|
|
|
|
|
tst r1, #UART_LSR_THRE
|
|
|
|
|
beq 2b
|
|
|
|
|
|
|
|
|
|
/* If the character that we just sent was a linefeed,
|
|
|
|
|
* then send a carriage return as well.
|
|
|
|
|
*/
|
|
|
|
|
|
|
|
|
|
teq r0, #'\n'
|
|
|
|
|
moveq r0, #'\r'
|
|
|
|
|
beq 1b
|
|
|
|
|
|
|
|
|
|
/* And return */
|
|
|
|
|
|
|
|
|
|
mov pc, lr
|
