i_swap.c

SkyEye是一个可以运行嵌入式操作系统的硬件仿真工具

/**********************************/
/*                                */
/*  Copyright 2000, David Grant   */
/*                                */
/*  see LICENSE for more details  */
/*                                */
/**********************************/

#include "coldfire.h"

/* Swap register halves (SWAP) instruction */

/* Format 
   
 15  14  13  12  11  10   9   8   7   6   5   4   3   2   1   0
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
| 0 | 1 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 |  Register |
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+

*/

int SWAPTime=1;


INSTRUCTION_2ARGS(SWAP,
	unsigned Code1,13,
	unsigned Register,3);

static void execute(void)
{
	struct _Address Destination;
	unsigned int DValue;
	unsigned int Tmp;
	SWAP_Instr Instr;
	Memory_RetrWordFromPC(&Instr.Code);

	if(!EA_GetFromPC(&Destination, 32, 0, Instr.Bits.Register)) return;
	EA_GetValue(&DValue, &Destination);
	Tmp = (DValue << 16) & 0xFFFF0000;
	Tmp += (DValue >> 16) & 0x0000FFFF;
	
	EA_PutValue(&Destination, Tmp);

	/* X - Not affected
	   N - Set if 32bits result is negative
	   Z - Set if 32bit result is zero
	   V - Always Cleared
	   C - Always Cleared
	*/
	SRBits->N= ((int)Tmp < 0) ? 1 : 0;
	SRBits->Z= (Tmp == 0) ? 1 : 0;
	SRBits->V=0;
	SRBits->C=0;

	cycle(SWAPTime);
	
	return;
}

static int disassemble(char *Instruction, char *Arg1, char *Arg2)
{
	SWAP_Instr Instr;
	Memory_RetrWordFromPC(&Instr.Code);

	sprintf(Instruction, "SWAP");

	Addressing_Print(32, 0, Instr.Bits.Register, Arg1);
	Arg2[0]=0;

	return 0;
}

int swap_5206_register(void)
{
	instruction_register(0x4840, 0xFFF8, &execute, &disassemble);
	return 1;
}