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/************************************************************************************
* arch/z80/src/z180/switch.h
* arch/z80/src/chip/switch.h
*
* 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.
*
************************************************************************************/
#ifndef __ARCH_Z80_SRC_Z180_SWITCH_H
#define __ARCH_Z80_SRC_Z180_SWITCH_H
/************************************************************************************
* Included Files
************************************************************************************/
#include <nuttx/sched.h>
#include <nuttx/arch.h>
#include <arch/io.h>
#include "z180_iomap.h"
#include "up_internal.h"
/************************************************************************************
* Pre-processor Definitions
************************************************************************************/
/* Macros for portability ***********************************************************
*
* Common logic in arch/z80/src/common is customized for the z180 context switching
* logic via the following macros.
*/
/* Initialize the IRQ state */
#define INIT_IRQCONTEXT() \
current_regs = NULL
/* IN_INTERRUPT returns true if the system is currently operating in the interrupt
* context. IN_INTERRUPT is the inline equivalent of up_interrupt_context().
*/
#define IN_INTERRUPT() \
(current_regs != NULL)
/* The following macro declares the variables need by IRQ_ENTER and IRQ_LEAVE.
* These variables are used to support nested interrupts.
*
* - savestate holds the previous value of current_state.
* - savecpr holds the previous value of current_cpr.
*
* NOTE: Nested interrupts are not supported in this implementation. If you want
* to implement nested interrupts, you would have to change the way that
* current_regs/cbr is handled. The savestate/savecbr variables would not work
* for that purpose as implemented here because only the outermost nested
* interrupt can result in a context switch (they can probabaly be deleted).
*/
#define DECL_SAVESTATE() \
FAR chipreg_t *savestate; \
uint8_t savecbr;
/* The following macro is used when the system enters interrupt handling logic.
* The entry values of current_regs and current_cbr and stored in local variables.
* Then current_regs and current_cbr are set to the values of the interrupted
* task.
*/
#define IRQ_ENTER(irq, regs) \
do \
{ \
savestate = (FAR chipreg_t *)current_regs; \
savecbr = current_cbr; \
current_regs = (regs); \
current_cbr = inp(Z180_MMU_CBR); \
} \
while (0)
/* The following macro is used when the system exits interrupt handling logic.
* The value of current_regs is restored. If we are not processing a nested
* interrupt (meaning that we going to return to the user task), then also
* set the MMU's CBR register.
*/
#define IRQ_LEAVE(irq) \
do \
{ \
current_regs = savestate; \
if (current_regs) \
{ \
current_cbr = savecbr; \
} \
else \
{ \
outp(Z180_MMU_CBR, savecbr); \
} \
} \
while (0)
/* The following macro is used to sample the interrupt state (as a opaque handle) */
#define IRQ_STATE() \
(current_regs)
/* Save the current IRQ context in the specified TCB */
#define SAVE_IRQCONTEXT(tcb) \
z180_copystate((tcb)->xcp.regs, (FAR chipreg_t*)current_regs)
/* Set the current IRQ context to the state specified in the TCB */
#define SET_IRQCONTEXT(tcb) \
do \
{ \
if ((tcb)->xcp.cbr) \
{ \
current_cbr = (tcb)->xcp.cbr->cbr; \
} \
z180_copystate((FAR chipreg_t*)current_regs, (tcb)->xcp.regs); \
} \
while (0)
/* Save the user context in the specified TCB. User context saves can be simpler
* because only those registers normally saved in a C called need be stored.
*/
#define SAVE_USERCONTEXT(tcb) \
z180_saveusercontext((tcb)->xcp.regs)
/* Restore the full context -- either a simple user state save or the full,
* IRQ state save.
*/
#define RESTORE_USERCONTEXT(tcb) \
do \
{ \
if ((tcb)->xcp.cbr) \
{ \
outp(Z180_MMU_CBR, (tcb)->xcp.cbr->cbr); \
} \
z180_restoreusercontext((tcb)->xcp.regs); \
} \
while (0)
/* Dump the current machine registers */
#define _REGISTER_DUMP() \
z180_registerdump()
/************************************************************************************
* Public Types
************************************************************************************/
/************************************************************************************
* Public Variables
************************************************************************************/
#ifndef __ASSEMBLY__
/* This holds a references to the current interrupt level register storage structure.
* If is non-NULL only during interrupt processing.
*/
extern 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.
*/
extern uint8_t current_cbr;
#endif
/************************************************************************************
* Public Function Prototypes
************************************************************************************/
#ifndef __ASSEMBLY__
#ifdef __cplusplus
extern "C"
{
#endif
/* Defined in z180_copystate.c */
void z180_copystate(FAR chipreg_t *dest, FAR const chipreg_t *src);
/* Defined in z180_saveusercontext.asm */
int z180_saveusercontext(FAR chipreg_t *regs);
/* Defined in z180_restoreusercontext.asm */
void z180_restoreusercontext(FAR chipreg_t *regs);
/* Defined in z180_sigsetup.c */
void z180_sigsetup(FAR struct tcb_s *tcb, sig_deliver_t sigdeliver, FAR chipreg_t *regs);
/* Defined in z180_registerdump.c */
void z180_registerdump(void);
#ifdef __cplusplus
}
#endif
#endif
#endif /* __ARCH_Z80_SRC_Z180_SWITCH_H */
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