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/************************************************************
* up_head.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/irq.h>
#include "up_internal.h"
.module up_head
.optsdcc -mmcs51 --model-large
/************************************************************
* Private Data
************************************************************/
.area REG_BANK_0 (REL,OVR,DATA)
.ds 8
/************************************************************
* Public Data
************************************************************/
.globl _g_irqtos
/************************************************************
* Public Functions
************************************************************/
.globl _irq_dispatch
/************************************************************
* Program entry points
************************************************************/
/* Program entry is through PROGRAM_BASE. This is just a
* branch to our start up logic.
*/
.area CODE1 (ABS)
.org PROGRAM_BASE
ljmp start
/* These are indirect interrupt vectors. Logic in PAULMON2,
* captures the interrupt vectors (near address 0x0000) and
* re-routes them through the following entry points.
*
* Each of these saves acc and ie then passes the IRQ number
* to higher level logic in a
*/
.org PM2_VECTOR_EXTINT0
push acc
mov a, #EXT_INT0_IRQ
ljmp _up_interrupt
.org PM2_VECTOR_TIMER0
push acc
mov a, #TIMER0_IRQ
ljmp _up_interrupt
.org PM2_VECTOR_EXTINT1
push acc
mov a, #EXT_INT1_IRQ
ljmp _up_interrupt
.org PM2_VECTOR_TIMER1
push acc
mov a, #TIMER1_IRQ
ljmp _up_interrupt
.org PM2_VECTOR_UART
push acc
mov a, #UART_IRQ
ljmp _up_interrupt
.org PM2_VECTOR_TIMER2
push acc
mov a, #TIMER2_IRQ
ljmp _up_interrupt
/************************************************************
* Name: start
*
* Description:
* This is the initial entry point into NuttX
*
************************************************************/
start:
mov sp, #(STACK_BASE-1)
ljmp _os_start
/************************************************************
* Name: up_interrupt
*
* Description:
* All interrupts vector to this point with:
*
* (1) acc on the stack and
* (2) the IRQ number in the accumulator
*
************************************************************/
_up_interrupt:
ar2 = 0x02
ar3 = 0x03
ar4 = 0x04
ar5 = 0x05
ar6 = 0x06
ar7 = 0x07
ar0 = 0x00
ar1 = 0x01
/* ACC already on the stack; push IE. Then disable interrupts */
push ie
clr ea
/* Now push the remaining registers with interrupt disabled */
push dpl
push dph
push b
push ar2
push ar3
push ar4
push ar5
push ar6
push ar7
push ar0
push ar1
push psw
clr psw
push _bp
/* Mark that we are in an interrupt */
mov dptr, #_g_irqtos
movx @dptr, a
/* Now call void irq_dispatch(int irq, FAR void *context)
*
* First, create the first argument as (int)irqno
*/
mov dpl, a
clr dph
/* Create the second argument (void *context) on the stack */
push sp
clr a
push acc
/* Then dispatch the IRQ. On return, the stack is off by
* by two because the above two pushes, but we fix that by
* reloading sp from g_irqtos below.
*/
lcall _irq_dispatch
/* Get the stackpointer. This might be the stack pointer that
* we increment above or it might be the stack pointer of a
* new task if the a context switch happened during the
* interrupt handling.
*/
mov dptr, #_g_irqtos
movx a, @dptr
mov sp, a
/* Indicate that we are no longer in an interrupt */
clr a
movx @dptr, a
/* Then return from the interrupt */
pop _bp
pop psw
pop ar1
pop ar0
pop ar7
pop ar6
pop ar5
pop ar4
pop ar3
pop ar2
pop b
pop dph
pop dpl
/* Restore the interrupt state per the stored IE value */
pop acc
jb acc.7, 00001$
clr ie.7
sjmp 00002$
00001$:
setb ie.7
00002$:
/* Finally pop off the ACC, which was the first register saved. */
pop acc
reti
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