nes-proj/cpu/arm/at91sam7s/interrupt-utils.h

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2009-07-11 14:22:45 +00:00
/*
* Defines and Macros for Interrupt-Service-Routines
* collected and partly created by
* Martin Thomas <mthomas@rhrk.uni-kl.de>
*
* Copyright 2005 M. Thomas
* No guarantees, warrantees, or promises, implied or otherwise.
* May be used for hobby or commercial purposes provided copyright
* notice remains intact.
*/
#ifndef interrupt_utils_
#define interrupt_utils_
/*
The following defines are usefull for
interrupt service routine declarations.
*/
/*
RAMFUNC
Attribute which defines a function to be located
in memory section .fastrun and called via "long calls".
See linker-skript and startup-code to see how the
.fastrun-section is handled.
The definition is not only useful for ISRs but since
ISRs should be executed fast the macro is defined in
this header.
*/
#define RAMFUNC __attribute__ ((long_call, section (".fastrun")))
/*
INTFUNC
standard attribute for arm-elf-gcc which marks
a function as ISR (for the VIC). Since gcc seems
to produce wrong code if this attribute is used in
thumb/thumb-interwork the attribute should only be
used for "pure ARM-mode" binaries.
*/
#define INTFUNC __attribute__ ((interrupt("IRQ")))
/*
NACKEDFUNC
gcc will not add any code to a function declared
"nacked". The user has to take care to save registers
and add the needed code for ISR functions. Some
macros for this tasks are provided below.
*/
#define NACKEDFUNC __attribute__((naked))
/******************************************************************************
*
* MACRO Name: ISR_STORE()
*
* Description:
* This MACRO is used upon entry to an ISR with interrupt nesting.
* Should be used together with ISR_ENABLE_NEST(). The MACRO
* performs the following steps:
*
* 1 - Save the non-banked registers r0-r12 and lr onto the IRQ stack.
*
*****************************************************************************/
#define ISR_STORE() asm volatile( \
"STMDB SP!,{R0-R12,LR}\n" )
/******************************************************************************
*
* MACRO Name: ISR_RESTORE()
*
* Description:
* This MACRO is used upon exit from an ISR with interrupt nesting.
* Should be used together with ISR_DISABLE_NEST(). The MACRO
* performs the following steps:
*
* 1 - Load the non-banked registers r0-r12 and lr from the IRQ stack.
* 2 - Adjusts resume adress
*
*****************************************************************************/
#define ISR_RESTORE() asm volatile( \
"LDMIA SP!,{R0-R12,LR}\n" \
"SUBS R15,R14,#0x0004\n" )
/******************************************************************************
*
* MACRO Name: ISR_ENABLE_NEST()
*
* Description:
* This MACRO is used upon entry from an ISR with interrupt nesting.
* Should be used after ISR_STORE.
*
*****************************************************************************/
#define ISR_ENABLE_NEST() asm volatile( \
"MRS LR, SPSR \n" \
"STMFD SP!, {LR} \n" \
"MSR CPSR_c, #0x1f \n" \
"STMFD SP!, {LR} " )
/******************************************************************************
*
* MACRO Name: ISR_DISABLE_NEST()
*
* Description:
* This MACRO is used upon entry from an ISR with interrupt nesting.
* Should be used before ISR_RESTORE.
*
*****************************************************************************/
#define ISR_DISABLE_NEST() asm volatile( \
"LDMFD SP!, {LR} \n" \
"MSR CPSR_c, #0x92 \n" \
"LDMFD SP!, {LR} \n" \
"MSR SPSR_cxsf, LR \n" )
/*
* The following marcos are from the file "armVIC.h" by:
*
* Copyright 2004, R O SoftWare
* No guarantees, warrantees, or promises, implied or otherwise.
* May be used for hobby or commercial purposes provided copyright
* notice remains intact.
*
*/
/******************************************************************************
*
* MACRO Name: ISR_ENTRY()
*
* Description:
* This MACRO is used upon entry to an ISR. The current version of
* the gcc compiler for ARM does not produce correct code for
* interrupt routines to operate properly with THUMB code. The MACRO
* performs the following steps:
*
* 1 - Adjust address at which execution should resume after servicing
* ISR to compensate for IRQ entry
* 2 - Save the non-banked registers r0-r12 and lr onto the IRQ stack.
* 3 - Get the status of the interrupted program is in SPSR.
* 4 - Push it onto the IRQ stack as well.
*
*****************************************************************************/
#define ISR_ENTRY() asm volatile(" sub lr, lr,#4\n" \
" stmfd sp!,{r0-r12,lr}\n" \
" mrs r1, spsr\n" \
" stmfd sp!,{r1}")
/******************************************************************************
*
* MACRO Name: ISR_EXIT()
*
* Description:
* This MACRO is used to exit an ISR. The current version of the gcc
* compiler for ARM does not produce correct code for interrupt
* routines to operate properly with THUMB code. The MACRO performs
* the following steps:
*
* 1 - Recover SPSR value from stack
* 2 - and restore its value
* 3 - Pop the return address & the saved general registers from
* the IRQ stack & return
*
*****************************************************************************/
#define ISR_EXIT() asm volatile(" ldmfd sp!,{r1}\n" \
" msr spsr_c,r1\n" \
" ldmfd sp!,{r0-r12,pc}^")
/******************************************************************************
*
* Function Name: disableIRQ()
*
* Description:
* This function sets the IRQ disable bit in the status register
*
* Calling Sequence:
* void
*
* Returns:
* previous value of CPSR
*
*****************************************************************************/
unsigned disableIRQ(void);
/******************************************************************************
*
* Function Name: enableIRQ()
*
* Description:
* This function clears the IRQ disable bit in the status register
*
* Calling Sequence:
* void
*
* Returns:
* previous value of CPSR
*
*****************************************************************************/
unsigned enableIRQ(void);
/******************************************************************************
*
* Function Name: restoreIRQ()
*
* Description:
* This function restores the IRQ disable bit in the status register
* to the value contained within passed oldCPSR
*
* Calling Sequence:
* void
*
* Returns:
* previous value of CPSR
*
*****************************************************************************/
unsigned restoreIRQ(unsigned oldCPSR);
/******************************************************************************
*
* Function Name: disableFIQ()
*
* Description:
* This function sets the FIQ disable bit in the status register
*
* Calling Sequence:
* void
*
* Returns:
* previous value of CPSR
*
*****************************************************************************/
unsigned disableFIQ(void);
/******************************************************************************
*
* Function Name: enableFIQ()
*
* Description:
* This function clears the FIQ disable bit in the status register
*
* Calling Sequence:
* void
*
* Returns:
* previous value of CPSR
*
*****************************************************************************/
unsigned enableFIQ(void);
/******************************************************************************
*
* Function Name: restoreFIQ()
*
* Description:
* This function restores the FIQ disable bit in the status register
* to the value contained within passed oldCPSR
*
* Calling Sequence:
* void
*
* Returns:
* previous value of CPSR
*
*****************************************************************************/
unsigned restoreFIQ(unsigned oldCPSR);
#endif