cpu_init.c

日本著名的的嵌入式实时操作系统T-Kernel的源码及用户手册。

/*
 *----------------------------------------------------------------------
 *    T-Kernel
 *
 *    Copyright (C) 2004 by Ken Sakamura. All rights reserved.
 *    T-Kernel is distributed under the T-License.
 *----------------------------------------------------------------------
 *
 *    Version:   1.01.00
 *    Released by T-Engine Forum(http://www.t-engine.org) at 2004/6/28.
 *
 *----------------------------------------------------------------------
 */

/*
 *	cpu_init.c (M32104)
 *	CPU-Dependent Initialization/Finalization
 */

#include "kernel.h"
#include "task.h"
#include "cpu_insn.h"

/* For saving monitor exception handler */
EXPORT MONHDR	SaveMonHdr;

/* available coprocessor */
EXPORT ATR	available_cop;

/*
 * CPU-dependant initialization
 */
EXPORT ER cpu_initialize( void )
{
IMPORT void dispatch_entry( void );	/* Dispatcher call */
IMPORT void call_entry( void );		/* System call */
IMPORT void _tk_ret_int( void );	/* 'tk_ret_int()' only call */
IMPORT void call_dbgspt( void );	/* Debugger support call */

	/* Save monitor exception handler */
	SaveMonHdr.default_hdr = SCArea->intvec[VECNO_DEFAULT];
	SaveMonHdr.monitor_hdr = SCArea->intvec[VECNO_MONITOR];
	SaveMonHdr.break_hdr   = SCArea->intvec[VECNO_BREAK];
	SaveMonHdr.icu2_hdr    = SCArea->intvec[VECNO_ICU2];
	SaveMonHdr.int5_hdr    = SCArea->intvec[VECNO_INT5];

	/* No available coprocessor */
	available_cop = TA_NULL;

	/* Register exception handler used on OS */
	define_inthdr(EIT_TRAP(TRAP_SVC),      call_entry);
	define_inthdr(EIT_TRAP(TRAP_RETINT),   _tk_ret_int);
	define_inthdr(EIT_TRAP(TRAP_DISPATCH), dispatch_entry);
#if USE_DBGSPT
	define_inthdr(EIT_TRAP(TRAP_DEBUG),    call_dbgspt);
#endif

	return E_OK;
}

/*
 * CPU-dependant finalization
 */
EXPORT void cpu_shutdown( void )
{
	/* Restore saved monitor exception handler */
	SCArea->intvec[VECNO_DEFAULT] = SaveMonHdr.default_hdr;
	SCArea->intvec[VECNO_MONITOR] = SaveMonHdr.monitor_hdr;
	SCArea->intvec[VECNO_BREAK]   = SaveMonHdr.break_hdr;
	SCArea->intvec[VECNO_ICU2]    = SaveMonHdr.icu2_hdr;
	SCArea->intvec[VECNO_INT5]    = SaveMonHdr.int5_hdr;
}

/* ------------------------------------------------------------------------- */

/*
 * Task exception handler startup reservation
 */
EXPORT void request_tex( TCB *tcb )
{
	/* Cannot set to the task operating at protected level 0 */
	if ( tcb->isysmode == 0 ) {
		tcb->reqdct = 0x80;
	}
}

/*
 * Task exception handler startup setting
 */
EXPORT FP setup_texhdr( INT *p_texcd )
{
	FP	texhdr;
	INT	texcd;
	UINT	m;

	/* Called in interrupt disable state */

	ctxtsk->reqdct = 0;  /* Free DCT */

	/* Get exception code */
	m = 0x00000001;
	for ( texcd = 0; texcd <= 31; texcd++ ) {
		if ( (ctxtsk->exectex & m) != 0 ) break;
		m <<= 1;
	}

	/* Exception does not occur /Exception is freed */
	if ( texcd > 31 ) return NULL;

	ctxtsk->exectex = 0;
	ctxtsk->pendtex &= ~m;
	ctxtsk->texflg |= ( texcd == 0 )? TEX0_RUNNING: TEX1_RUNNING;
	texhdr = ctxtsk->texhdr;

	ENABLE_INTERRUPT;

	*p_texcd = texcd;

	return texhdr;
}