一个小型虚拟机的实现代码

				#include				#include								#define U1 unsigned char								void printBinary(U1 nbr)				{					U1 i;					printf("[");					for(i=128;i>0;i=i/2)					{						if(nbr&i){ printf("1"); }						else{ printf("0"); }					}					printf("]");					return;				}/*end printBinary*/								/*-----------------------------------------------------------------*/								void printFloat(char *str)				{					float f;					U1 *uptr;					int i;									f = (float)atof(str);					uptr = (U1*)&f;									printf("FLOAT=%f\n",f);										printf("DEC [0]->[3]\t");					for(i=0;i					printf("\n");									printf("DEC [3]->[0]\t");					for(i=3;i>=0;i--){ printf("[%+4d]",uptr[i]); }					printf("\n");									printf("HEX [0]->[3]\t");					for(i=0;i					printf("\n");									for(i=0;i					{ 						printf("BIN [%u]\t",i);						printBinary(uptr[i]);						printf("\n");					}					printf("\n");									printf("FLOAT=%f\n",*((float*)uptr));									return;				}/*end printFloat*/								/*-----------------------------------------------------------------*/								void printDouble(char *str)				{					double d;					U1 *uptr;					int i;									d = atof(str);					uptr = (U1*)&d;									printf("DOUBLE=%f\n",d);										printf("DEC [0]->[7]\t");					for(i=0;i					printf("\n");									printf("DEC [7]->[0]\t");					for(i=7;i>=0;i--){ printf("[%+4d]",uptr[i]); }					printf("\n");									printf("HEX [0]->[7]\t");					for(i=0;i					printf("\n");									for(i=0;i					{ 						printf("BIN [%u]\t",i);						printBinary(uptr[i]);						printf("\n");					}					printf("\n");									printf("DOUBLE=%f\n",*((double*)uptr));					return;				}/*end printDouble*/								/*-----------------------------------------------------------------*/								void printInteger(char *str)				{					long long I;					float f;					U1 *uptr;					int i;									f = atof(str);					I = (long long)f;					uptr = (U1*)&I;									printf("S8=%lld\n",I);										printf("DEC [0]->[7]\t");					for(i=0;i					printf("\n");									printf("DEC [7]->[0]\t");					for(i=7;i>=0;i--){ printf("[%+4d]",uptr[i]); }					printf("\n");									printf("HEX [0]->[7]\t");					for(i=0;i					printf("\n");									for(i=0;i					{ 						printf("BIN [%u]\t",i);						printBinary(uptr[i]);						printf("\n");					}					printf("\n");									printf("S8=%lld\n",*((long long*)uptr));					return;				}/*end printInteger*/								/*-----------------------------------------------------------------*/								void printChar(char *str)				{					char u;					U1 *uptr;									u = str[0];					uptr = &u;									printf("CHAR=%c\n",u);									printf("DEC\t");					printf("[%-4d]",uptr[0]);					printf("\n");									printf("HEX\t");					printf("[%-4x]",uptr[0]); 					printf("\n");									printf("BIN\t");					printBinary(uptr[0]);					printf("\n");									printf("CHAR=%c\n",*uptr);					return;				}/*end printChar*/								/*-----------------------------------------------------------------*/								void printUsage()				{					printf("\n\tusage: bformat type  value\n\n");					printf("\tdisplays byte-wise decomposition of value\n\n");					printf("\ttype:\n");					printf("\td=double\n");					printf("\tf=float\n");					printf("\ti=integer\n");					printf("\tc=ASCII char\n");					return;				}/*end printUsage*/								/*-----------------------------------------------------------------*/								void main(int argc, char*arg[])				{					char opcode;					if((arg[1]==NULL)||(arg[2]==NULL))					{						printf("Not enough arguments\n");						printUsage();						return;					}					opcode = arg[1][0];					switch(opcode)					{						case 'f':{printFloat(arg[2]);}break;						case 'd':{printDouble(arg[2]);}break;						case 'i':{printInteger(arg[2]);}break;						case 'c':{printChar(arg[2]);}break;						default:						{							printf("Bad opcode");							printUsage();							return;						}					}					return;								}/*end main*/