#include <reg51.h>
float numb;
char digit; 
char xdata mas[8];
char m=1;
char mm;
int i = 0;
void Int00(void) interrupt 0 
{
char x=P3;
switch (x)
{ case 0x7b: digit='1'; break;
case 0x79: digit='2'; break;
case 0x78: digit='3'; break;
case 0xbb: digit='4'; break;
case 0xb9: digit='5'; break;
case 0xb8: digit='6'; break;
case 0xdb: digit='7'; break;
case 0xd9: digit='8'; break;
case 0xd8: digit='9'; break;
case 0xeb: digit='0'; break;
case 0xe9: digit=','; break;
case 0xe8: digit='e'; break;
default: digit=0xff;
}
if(digit==',') {mm=m; mas[i++]=digit;
digit=0xff;}
if(digit=='e')
{ digit=0xff ; numb/=mm; }
if (digit!=0xff)
{ mas[i++]=digit; 
m*=10;
numb=numb*10+(digit&0x0f);
}

while(~INT0); 

}
main ()
{
EX0=1; 
IT0=1; 
EA=1;
while (1);
}