mirror of
https://github.com/FliegendeWurst/ieee754-interpreter.git
synced 2024-11-08 08:20:36 +00:00
Denormalized floats
This commit is contained in:
parent
e32878d723
commit
0a8e357d3d
19
src/main.rs
19
src/main.rs
@ -41,8 +41,7 @@ fn interpret_single(float: u32) -> f32 {
|
||||
|
||||
if characteristic == 0 {
|
||||
if mantissa != 0 {
|
||||
eprintln!("can't process denormalized floats (yet)");
|
||||
return 0.0;
|
||||
// denormalized value, handled below
|
||||
} else {
|
||||
return sign * 0.0;
|
||||
}
|
||||
@ -54,24 +53,30 @@ fn interpret_single(float: u32) -> f32 {
|
||||
}
|
||||
}
|
||||
|
||||
let mut power = 2.0f32.powi(characteristic as i32 - 127);
|
||||
let mut value = sign * power;
|
||||
let mut power = if characteristic != 0 { 2.0f32.powi(characteristic as i32 - 127) } else { 2.0f32.powi(-126) };
|
||||
let mut value = if characteristic != 0 { power } else { 0.0 };
|
||||
for idx in 0..23 {
|
||||
let digit = (mantissa >> (22 - idx)) & 1;
|
||||
power /= 2.0;
|
||||
if digit == 1 {
|
||||
value += sign * power;
|
||||
value += power;
|
||||
}
|
||||
}
|
||||
value
|
||||
value.copysign(sign)
|
||||
}
|
||||
|
||||
#[test]
|
||||
fn interpret_single_test() {
|
||||
let tests = [
|
||||
(0b1100_0000_1110_1000_0000_0000_0000_0000, -7.25),
|
||||
(0b1011_1111_0101_0000_0000_0000_0000_0000, -0.8125)
|
||||
(0b1011_1111_0101_0000_0000_0000_0000_0000, -0.8125),
|
||||
// denormalized float
|
||||
(0b0000_0000_0100_0000_0000_0000_0000_0000, 0.000000000000000000000000000000000000005877472),
|
||||
];
|
||||
// some sanity checks around subnormals
|
||||
assert_eq!(2.0f32.powi(-127), tests[2].1);
|
||||
assert_ne!(tests[2].1 / 2.0, 0.0);
|
||||
assert_eq!(2.0f32.powi(-127) / 2.0, tests[2].1 / 2.0);
|
||||
for test in &tests {
|
||||
assert_eq!(interpret_single(test.0), test.1);
|
||||
}
|
||||
|
Loading…
Reference in New Issue
Block a user