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author | patacongo <patacongo@42af7a65-404d-4744-a932-0658087f49c3> | 2007-04-28 19:39:18 +0000 |
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committer | patacongo <patacongo@42af7a65-404d-4744-a932-0658087f49c3> | 2007-04-28 19:39:18 +0000 |
commit | cfa89740728582ffd77b868c732c45cef8c20ea9 (patch) | |
tree | 14e026aaf0cc6b424581434e0986f367d69adfc7 /nuttx/arch/arm/src/dm320/dm320_lowputc.S | |
parent | 02755ff439dd361643294af1c10937845d848f69 (diff) | |
download | px4-nuttx-cfa89740728582ffd77b868c732c45cef8c20ea9.tar.gz px4-nuttx-cfa89740728582ffd77b868c732c45cef8c20ea9.tar.bz2 px4-nuttx-cfa89740728582ffd77b868c732c45cef8c20ea9.zip |
Common ARM support
git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@187 42af7a65-404d-4744-a932-0658087f49c3
Diffstat (limited to 'nuttx/arch/arm/src/dm320/dm320_lowputc.S')
-rw-r--r-- | nuttx/arch/arm/src/dm320/dm320_lowputc.S | 127 |
1 files changed, 127 insertions, 0 deletions
diff --git a/nuttx/arch/arm/src/dm320/dm320_lowputc.S b/nuttx/arch/arm/src/dm320/dm320_lowputc.S new file mode 100644 index 000000000..c27918262 --- /dev/null +++ b/nuttx/arch/arm/src/dm320/dm320_lowputc.S @@ -0,0 +1,127 @@ +/************************************************************************** + * dm320/dm320_lowputc.S + * + * Copyright (C) 2007 Gregory Nutt. All rights reserved. + * Author: Gregory Nutt <spudmonkey@racsa.co.cr> + * + * 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 Gregory Nutt 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 "up_internal.h" +#include "up_arch.h" + +/************************************************************************** + * Private 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 */ + +#ifdef CONFIG_UART0_SERIAL_CONSOLE + ldr r2, =DM320_UART0_REGISTER_BASE /* r2=UART0 base */ +#else + ldr r2, =DM320_UART1_REGISTER_BASE /* r2=UART1 base */ +#endif + + /* Poll the TX fifo trigger level bit of the UART_SSR + * register. When the bit is non-zero, the TX FIFO is no + * longer full + */ + +1: ldrh r1, [r2, #UART_SR] + tst r1, #UART_SR_TFTI + beq 1b + + /* Send the character by writing it into the UART_DTRR + * register. + */ + + strh r0, [r2, #UART_DTRR] + + /* Wait for the tranmsit regiser to be emptied. This is + * detemined when TX register empty bit of the SR is zero. + */ + +2: ldrh r1, [r2, #UART_SR] + tst r1, #UART_SR_TREF + bne 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 + |