Read 80-bit Extended Floating Point Numbers from buffers
MIT License
Read 80-bit Extended Floating Point Numbers from buffers
It turns out that there does not appear to be any way to read the extended precision floating point format in Javascript, aka "long doubles".
Until now, anyway.
Get this library with
$ npm install float80
>>> const {Float80} = require('float80')
>>> f = Float80.fromBytes([0x3f, 0xff, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00])
>>> f.toString()
1
>>> f.asNumber()
<BigNumber: [String: 1]>
The number parsed by Float80 is stored in a BigNumber instance, and exposed by the asNumber
function.
Here is a trivial C program that you can use to view how 80-bit floats are represented:
#include <stdio.h>
union {
long double value;
unsigned char bytes[10];
} dc;
int main(int argc, char ** argv) {
int i;
while(1) {
printf("Enter long double: ");
scanf("%Lf", &dc.value);
for (i = 0; i < 10; ++i) {
printf("%02x ", dc.bytes[9 - i]);
}
printf("\n");
}
}
The weird 48-bit float parsing is available in Float48
class.
Same API as Float80
.
MIT