nes-proj/cpu/cc2538/dev/nvic.c
Benoît Thébaudeau 19fd7a3551 Use additive offsets
OR-ing an offset to a base address instead of adding it is dangerous
because it can only work if the base address is aligned enough for the
offset.

Moreover, if the base address or the offset has a value unknown at
compile time, then the assembly instructions dedicated to 'base +
offset' addressing on most CPUs can't be emitted by the compiler because
this would require the alignment of the base address against the offset
to be known in order to optimize 'base | offset' into 'base + offset'.
In that case, the compiler has to emit more instructions in order to
compute 'base | offset' on most CPUs, e.g. on ARM, which means larger
binary size and slower execution.

Hence, replace all occurrences of 'base | offset' with 'base + offset'.
This must become a coding rule.

Here are the results for the cc2538-demo example:
 - Compilation of uart_init():
    * before:
        REG(regs->base | UART_CC) = 0;
        200b78:	f446 637c 	orr.w	r3, r6, #4032	; 0xfc0
        200b7c:	f043 0308 	orr.w	r3, r3, #8
        200b80:	2200      	movs	r2, #0
        200b82:	601a      	str	r2, [r3, #0]

    * now:
        REG(regs->base + UART_CC) = 0;
        200b7a:	2300      	movs	r3, #0
        200b7c:	f8c4 3fc8 	str.w	r3, [r4, #4040]	; 0xfc8

 - Size of the .text section:
    * before:	0x4c7c
    * now:	0x4c28
    * saved:	84 bytes

Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau.dev@gmail.com>
2015-03-28 17:28:15 +01:00

112 lines
3.8 KiB
C

/*
* Copyright (c) 2012, Texas Instruments Incorporated - http://www.ti.com/
* All rights reserved.
*
* 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 of the copyright holder 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 HOLDER 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.
*/
/**
* \addtogroup cc2538-nvic
* @{
*
* \file
* Driver for the cc2538 NVIC
* All interrupt-related functionality is implemented here
*/
#include "contiki.h"
#include "dev/nvic.h"
#include "dev/scb.h"
#include "reg.h"
#include <stdint.h>
static uint32_t *interrupt_enable;
static uint32_t *interrupt_disable;
static uint32_t *interrupt_pend;
static uint32_t *interrupt_unpend;
/*---------------------------------------------------------------------------*/
void
nvic_init()
{
interrupt_enable = (uint32_t *)NVIC_EN0;
interrupt_disable = (uint32_t *)NVIC_DIS0;
interrupt_pend = (uint32_t *)NVIC_PEND0;
interrupt_unpend = (uint32_t *)NVIC_UNPEND0;
/* Provide our interrupt table to the NVIC */
REG(SCB_VTABLE) = (NVIC_CONF_VTABLE_BASE + NVIC_CONF_VTABLE_OFFSET);
}
/*---------------------------------------------------------------------------*/
void
nvic_interrupt_enable(uint32_t intr)
{
/* Writes of 0 are ignored, which is why we can simply use = */
interrupt_enable[intr >> 5] = 1 << (intr & 0x1F);
}
/*---------------------------------------------------------------------------*/
void
nvic_interrupt_disable(uint32_t intr)
{
/* Writes of 0 are ignored, which is why we can simply use = */
interrupt_disable[intr >> 5] = 1 << (intr & 0x1F);
}
/*---------------------------------------------------------------------------*/
void
nvic_interrupt_en_restore(uint32_t intr, uint8_t v)
{
if(v != 1) {
return;
}
interrupt_enable[intr >> 5] = 1 << (intr & 0x1F);
}
/*---------------------------------------------------------------------------*/
uint8_t
nvic_interrupt_en_save(uint32_t intr)
{
uint8_t rv = ((interrupt_enable[intr >> 5] & (1 << (intr & 0x1F)))
> NVIC_INTERRUPT_DISABLED);
nvic_interrupt_disable(intr);
return rv;
}
/*---------------------------------------------------------------------------*/
void
nvic_interrupt_pend(uint32_t intr)
{
/* Writes of 0 are ignored, which is why we can simply use = */
interrupt_pend[intr >> 5] = 1 << (intr & 0x1F);
}
/*---------------------------------------------------------------------------*/
void
nvic_interrupt_unpend(uint32_t intr)
{
/* Writes of 0 are ignored, which is why we can simply use = */
interrupt_unpend[intr >> 5] = 1 << (intr & 0x1F);
}
/** @} */