cycle.c

SkyEye是一个可以运行嵌入式操作系统的硬件仿真工具

/**********************************/
/*                                */
/*  Copyright 2003, David Grant   */
/*                                */
/*  see LICENSE for more details  */
/*                                */
/**********************************/

/* August 2000: Matt Minnis 
 * March 2003: David Grant -- Rewrote everything for speed */


#include <stdio.h>

#include "coldfire.h"

void cycle(unsigned int number)
{
	extern struct _board_data board_data;
	if(number < 1) return; /* ignore 0 and -1 times since they are invalid */
	board_data.cycle_count += number;
	return;
}

/* Lookup table for getting the right offset in the timing tables
 * in each instruction */
static short cycle_EA_lookup[] = { 0, 0, 1, 2, 3, 4, 5, 6, 6, 4, 5, 7 };

int cycle_EA(short reg, short mode)
{
	if(mode == 7) return cycle_EA_lookup[reg+7];
	return cycle_EA_lookup[mode];
}

#ifdef explanation_of_what_the_above_routine_is_doing
int MoveCycle_EA (int Register, int Mode)    (These two are the same)
int Cycle_EA (int Register, int Mode)
{    
	switch (Mode)	/* Return value 0-7 for destination addressing. */
	{
    	case 0:  return sDRD;  /* Dy */
    	case 1:  return sDRD;  /* Ay */
    	case 2:  return sARI;  /* (Ay) */
    	case 3:  return sARIPO;  /* (Ay)+ */
    	case 4:  return sARIPR;  /* -(Ay) */
    	case 5:  return sARID;  /* (d16,Ay) */
    	case 6:  return sARIIB;  /* (d8,An,Xi) */
    	case 7: switch (Register) 
        	{
                	case 0:  return sAS; /* word addressing */
                      	case 1:  return sAS; /* long addressing */
                     	case 2:  return sARID; /* (d16,PC) */
                      	case 3:  return sARIIB; /* (d8,PC,Xi) */
                      	case 4:  return sIM; /* (d8,PC,Xi) */
                }
                break;
    	
	}
	/* This can cause a segfault, this returns an offset, returning -1 is bad (DG) */
	return -1;  /* Shouldn't get here */
}
#endif