一个小型虚拟机的实现代码
源代码在线查看： numfmt.c
#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)
{
__int64 I;
U1 *uptr;
int i;
I = _atoi64(str);
uptr = (U1*)&I;
printf("S8=%I64d\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=%I64d\n",*((__int64*)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 printWideChar(char *str)
{
__int64 I;
wchar_t wc;
U1 *uptr;
I = _atoi64(str);
wc = (wchar_t)I;
uptr = (U1*)&wc;
wprintf(L"CHAR=%c\n",wc);
printf("DEC [0][1]\t");
printf("[%-4d]",uptr[0]);
printf("[%-4d]",uptr[1]);
printf("\n");
printf("HEX [0][1]\t");
printf("[%-4x]",uptr[0]);
printf("[%-4x]",uptr[1]);
printf("\n");
printf("BIN [0][1]\t");
printBinary(uptr[0]);
printBinary(uptr[1]);
printf("\n");
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");
printf("\tw=16-bit char\n\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;
case 'w':{printWideChar(arg[2]);}break;
default:
{
printf("Bad opcode");
printUsage();
return;
}
}
return;
}/*end main*/
