Files
retrobsd/src/cmd/mathtest/mathtest.c
2014-04-19 10:31:25 +01:00

50 lines
1.0 KiB
C

// Pito 12/2013
#include <stdio.h>
#include <math.h>
// print out double (IEEE 64bit) variable in HEX
// ie. 9.0 is 4022000000000000
// more on http://babbage.cs.qc.cuny.edu/IEEE-754/
void print64x( double x ) {
const unsigned char* p;
int j;
p = (unsigned char *) &x;
printf("%02X", p[7]);
printf("%02X", p[6]);
printf("%02X", p[5]);
printf("%02X", p[4]);
printf("%02X", p[3]);
printf("%02X", p[2]);
printf("%02X", p[1]);
printf("%02X", p[0]);
}
void print32x( float x ) {
const char* p;
int j;
p = (char *) &x;
for( j=0; j< sizeof(x); j++) {
printf("%02X", p[(sizeof(x)-1)-j]&0xFF);
}
}
int main() {
volatile double num1 = 1.2499999999999998193580478994e-10;
volatile double num2 = 2.16000000000000081281633984229e-10;
volatile double res = 0;
res = num1 + num2;
// print64x(num1);
// printf(" + ");
// print64x(num2);
// printf(" = ");
// print64x(res);
// printf("\n");
printf("%1.15e + %1.15e = %1.15e\n", num1, num2, res);
return 0;
}