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/****************************************************************************
* arch/z80/src/z180/z180_irq.c
*
* Copyright (C) 2012 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* 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 <stdint.h>
#include <nuttx/arch.h>
#include <nuttx/irq.h>
#include <arch/io.h>
#include "switch.h"
#include "z180_iomap.h"
#include "up_internal.h"
/****************************************************************************
* Private Definitions
****************************************************************************/
/****************************************************************************
* Public Data
****************************************************************************/
/* This holds a references to the current interrupt level register storage
* structure. If is non-NULL only during interrupt processing.
*/
volatile chipreg_t *current_regs;
/* This holds the value of the MMU's CBR register. This value is set to the
* interrupted tasks's CBR on interrupt entry, changed to the new task's CBR if
* an interrrupt level context switch occurs, and restored on interrupt exit. In
* this way, the CBR is always correct on interrupt exit.
*/
uint8_t current_cbr;
/* The interrupt vector table is exported by z180_vectors.asm or
* z180_romvectors.asm with the name up_vectors:
*/
extern uintptr_t up_vectors[16];
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: z180_seti
*
* Description:
* Input byte from port p
*
****************************************************************************/
static void z180_seti(uint8_t value) __naked
{
__asm
ld a, 4(ix) ;value
ld l, a
__endasm;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: irqsave
*
* Description:
* Disable all interrupts; return previous interrupt state
*
****************************************************************************/
irqstate_t irqsave(void) __naked
{
__asm
ld a, i ; AF Parity bit holds interrupt state
di ; Interrupts are disabled
push af ; Return AF in HL
pop hl ;
ret ;
__endasm;
}
/****************************************************************************
* Name: irqrestore
*
* Description:
* Restore previous interrupt state
*
****************************************************************************/
void irqrestore(irqstate_t flags) __naked
{
__asm
di ; Assume disabled
pop hl ; HL = return address
pop af ; AF Parity bit holds interrupt state
jp po, statedisable
ei
statedisable:
push af ; Restore stack
push hl ;
ret ; and return
__endasm;
}
/****************************************************************************
* Name: up_irqinitialize
*
* Description:
* Initialize and enable interrupts
*
****************************************************************************/
void up_irqinitialize(void)
{
uint16_t vectaddr = (uint16_t)up_vectors;
uint8_t regval;
/* Initialize the I and IL registers so that the interrupt vector table
* is used.
*/
regval = (uint8_t)(vectaddr >> 8);
z180_seti(regval);
regval = (uint8_t)(vectaddr & IL_MASK);
outp(Z180_INT_IL, regval);
/* Disable external interrupts */
outp(Z180_INT_ITC, 0);
/* And finally, enable interrupts (including the timer) */
#ifndef CONFIG_SUPPRESS_INTERRUPTS
irqrestore(Z180_C_FLAG);
#endif
}
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