cpu.c

一个小型化的嵌入式实时操作系统源代码

/*
; -------------------------------------------------------------------
; File: cpu.c
;
; SPARCLite-specific stuff for the uC/OS Real-time multitasking kernel
;
; Written by Brad Denniston ([e-mail]) Sept 1998
; Based on MIPS port by Phil Bunce
; -------------------------------------------------------------------
*/
#include	"ucos.h"
#include 	"cpu.h"
#include	"bsp.h"

uint	debval1;
uint	debval2;
uint	debval3;
uint	debval4;

/* REMOVE */ uint OSIntNesting = 0;	/* defined in os.c */

PFV IRQVector[] = 
{
	0,	/* 0 */
	0,	/* 1 */
	0,	/* 2 */
	0,	/* 3 */
	0,	/* 4 */
	0,	/* 5 */
	0,	/* 6 */
	0,	/* 7 */
	0,	/* 8 */
	0,	/* 9 */
	0,	/* 10 */
	OSTimeTick,	/* 11 */
	0,	/* 12 */
	0,	/* 13 */
	0,	/* 14 */
	0	/* 15 */
};

/*
; -------------------------------------------------------------------
; CPUInit - set the processor up. This calls BSPInit.
; -------------------------------------------------------------------
*/
void
CPUInit()
{
	int		interrupt_number;

	BSPInit(); 

	/* Set up one interrupt handler for all hardware interrupts */
#if 0
  	for(interrupt_number = 1; interrupt_number < 16; interrupt_number++ )
	{
      	exceptionHandler( interrupt_number + 16, IRQTrap );
	}
#else
	interrupt_number = 11;
    exceptionHandler( interrupt_number + 16, IRQTrap );
#endif
}

/*
; -------------------------------------------------------------------
; Interrupt service routine dispatcher.
;
; This is the IRQ handler called by IRQTrap when hardware interrupts occur.
; InterruptNumber - 1 thru 15 are legal. 11 is the timer. 
; Note: When this is called, higher level interrupts may occur causing nesting
;
; Return:
;		1 (any non-zero) if context switch needed
; -------------------------------------------------------------------
*/
int
CPUDispatchIRQ( uint InterruptNumber )
{
char	ch;

	/* increment nesting counter */
	OSIntNesting++;

	/* call registered interrupt handler */
	if (InterruptNumber > 0 && InterruptNumber < 16 && IRQVector[InterruptNumber])
	{		
		(*(IRQVector[InterruptNumber]))();
	}
	return( OSIntExit() ); 
} /* DispatchIRQ */
 

/*
; -------------------------------------------------------------------
;  PFV IRQInstall - Install and enable a new Interrupt Service Routine.
;
; int IRQNum - interrupt request number
; PFV ISRFun - new interrupt handler
;
; Return:
;     The old interrupt service routine address.
; -------------------------------------------------------------------
*/
PFV
IRQInstall( int IRQNumber, PFV ISRFunction )
{
	PFV OldISR;
 
	/* Sanity check */
	if (IRQNumber < 1 || IRQNumber >= 15)
		return((PFV)0);
 
	/* Get old ISR function */
	OldISR = IRQVector[IRQNumber];
 
	/* Replace with new ISR function */
	IRQVector[IRQNumber] = ISRFunction;
 
#if 0
	/* Enable the interrupt */ BRAD - TBD
	IRQIntEnable( IRQNumber );
#endif
 
	return( OldISR );
} /* IRQInstall */

/*
; -------------------------------------------------------------------
; GetTbr - assembly language routine to get value of tbr
;	Leafless function - no register context switch
; -------------------------------------------------------------------
*/
asm("
	.text
	.align 8
	.global _GetTbr
_GetTbr:
	retl
	mov		%tbr, %o0
");

/*
; -------------------------------------------------------------------
; Getfp - assembly language routine to get value of fp 
;	Leafless function - no register context switch
; -------------------------------------------------------------------
*/
asm("
	.text
	.align 8
	.global _Getfp
_Getfp:
	retl
	mov		%fp, %o0
");

/*
; -------------------------------------------------------------------
; GetPsr - assembly language routine to get value of psr
;	Leafless function - no register context switch
; -------------------------------------------------------------------
*/
asm("
	.text
	.align 8
	.global _GetPsr
_GetPsr:
	retl
	mov		%psr, %o0
");

/*
; -------------------------------------------------------------------
;  uint *BuildNewStack(uint *stk,PTV task,void *pdata)
; This will be the first register window. 
; Must set %pc, %psr and %sp.
; Values of other registers does not matter. 
; Put pointer to task name into the return value (%o0).
; -------------------------------------------------------------------
*/
uint *BuildNewStack(uint *stk,PTV task,void *pdata)
{
	uint	*frame_pointer;

	frame_pointer = stk;
	stk -= DEFAULT_STACK_FRAME;		/* reserve space on stack for reg win */

	/* (stk +35..+31) %psr, %wim, %y, %tbr  */
	/* use current %psr and %tbr */
	*(stk + 35) = GetPsr();		/* TRAPS ENABLED */
	/* %y don't care, %wim will be computed at startup */
	*(stk + 32) = GetTbr();


	/* (stk +31..+24) %o7..%o0 */
	*(stk + 31) = (uint)task - 8;	/* %o7 - Task entry point for retl */
	*(stk + 30) = (uint)(stk);		/* %o6 - Task stack address */
									/* %o5..%o1 - don't care */
	*(stk + 24) = (uint)pdata;		/* %o0 - stack name into return value */

	/* (stk +23..+16) %g7..%g0 */
									/* %g7..%g0 - don't care */	

	/* (stk +8..+15) %i7..%i0 */
	*(stk + 15) = 0;				/* %i7 - RETURN ADDRESS??? - need task killer */
	*(stk + 14) = (uint)frame_pointer;	/* %i6 - use initial stack pointer */
	*(stk + 8) = (uint)pdata;		/* %i0 - pass pointer to task name */

	/* (stk +7..+0) %l7..%l0 */
									/* %l7..%l0 - don't care */	

	return(stk);
}

/*
; -------------------------------------------------------------------
; itoa - converts integer to a string, 32 characters max
; -------------------------------------------------------------------
*/
void
itoa (
	uint 	value,
	char	*buffer,
	uint	base
	)
{
	char	*pbuf, *ptmp;
	char	tmp[32];
	char	least_sig_digit;

	ptmp = tmp;
	if( value == 0 )
		*ptmp++ = '0';
	else while( value > 0 )
	{
		least_sig_digit = (char)(value - (value/base * base));
		value = value / base;
		*ptmp++ = least_sig_digit + 0x30;
	}
	pbuf = buffer;
	while( ptmp > tmp )
		*pbuf++ = *--ptmp;
	*pbuf = 0;
}


/*
; -------------------------------------------------------------------
; putstr
; -------------------------------------------------------------------
*/
void
putstr( char *buf )
{
	while( *buf )
		putchar( *buf++ );
}