Double compare
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#include <stdio.h>
#include <stdint.h>
#include <stdbool.h>
#include <stdlib.h>
typedef int64_t s64;
typedef uint64_t u64;
typedef int64_t s8;
typedef double f64;
typedef bool b8;
u64 f64Tos64(f64 a)
{
s64 Result = *((s64 *)&a);
return Result;
}
f64 s64Tof64(s64 a)
{
f64 Result = *((f64 *)&a);
return Result;
}
b8 Compare(f64 in_a, f64 in_b, s8 Shift)
{
s64 a = f64Tos64(in_a);
s64 b = f64Tos64(in_b);
// Verify:
// How exponet reacts.
// Compare on exponet first?
// Assert shift is no higher than mantissa.
return labs(a-b) <= (2 << Shift);
}
int main()
{
f64 a = 0.30000000000001; // Equal
// f64 a = 0.3000000000001; // Not Equal
f64 b = 0.3;
printf("%f\n",a);
printf("%lx\n",f64Tos64(a));
printf("%f\n",b);
printf("%lx\n",f64Tos64(b));
printf("%li\n",f64Tos64(3.0) - f64Tos64(0.3));
printf("-0.0 - 0.0: %li\n",f64Tos64(-0.0) - f64Tos64(0.0)); // Problems :(
printf("%li\n",Compare(f64Tos64(-0.0), f64Tos64(0.0), 8));
if(Compare(b,a,8))
{
printf("yay?\n");
}
else
{
printf("nay\n");
}
return 0;
}
C
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