38 lines
1.1 KiB
Zig
38 lines
1.1 KiB
Zig
//! Utilities for dealing with the `long double` type (`f80` or `f128`)
|
|
|
|
const std = @import("std");
|
|
|
|
pub const U80 = std.meta.Int(.unsigned, 80);
|
|
|
|
/// Returns the sign + exponent bits of a `long double`
|
|
pub fn signExponent(x: anytype) u16 {
|
|
const T = @TypeOf(x);
|
|
switch (T) {
|
|
f80 => {
|
|
const bits: U80 = @bitCast(x);
|
|
return @intCast(bits >> 64);
|
|
},
|
|
f128 => {
|
|
const bits: u128 = @bitCast(x);
|
|
return @intCast(bits >> 112);
|
|
},
|
|
else => @compileError("`signExponent` supports only `f80` and `f128`, got: " ++ @typeName(T)),
|
|
}
|
|
}
|
|
|
|
/// Takes the top 16 bits of a `long double`'s mantissa
|
|
pub fn mantissaTop(x: anytype) u16 {
|
|
const T = @TypeOf(x);
|
|
switch (T) {
|
|
f80 => {
|
|
const bits: U80 = @bitCast(x);
|
|
return @intCast((bits >> 48) & 0xFFFF);
|
|
},
|
|
f128 => {
|
|
const bits: u128 = @bitCast(x);
|
|
return @intCast((bits >> 96) & 0xFFFF);
|
|
},
|
|
else => @compileError("`mantissaTop` supports only `f80` and `f128`, got: " ++ @typeName(T)),
|
|
}
|
|
}
|