zig/std/math/isnormal.zig
Marc Tiehuis 4c16f9a3c3 Add math library
This covers the majority of the functions as covered by the C99
specification for a math library.

Code is adapted primarily from musl libc, with the pow and standard
trigonometric functions adapted from the Go stdlib.

Changes:

 - Remove assert expose in index and import as needed.
 - Add float log function and merge with existing base 2 integer
   implementation.

See https://github.com/tiehuis/zig-fmath.
See #374.
2017-06-16 20:32:31 +12:00

27 lines
703 B
Zig

const math = @import("index.zig");
const assert = @import("../debug.zig").assert;
pub fn isNormal(x: var) -> bool {
const T = @typeOf(x);
switch (T) {
f32 => {
const bits = @bitCast(u32, x);
(bits + 0x00800000) & 0x7FFFFFFF >= 0x01000000
},
f64 => {
const bits = @bitCast(u64, x);
(bits + (1 << 52)) & (@maxValue(u64) >> 1) >= (1 << 53)
},
else => {
@compileError("isNormal not implemented for " ++ @typeName(T));
},
}
}
test "isNormal" {
assert(!isNormal(math.nan(f32)));
assert(!isNormal(math.nan(f64)));
assert(isNormal(f32(1.0)));
assert(isNormal(f64(1.0)));
}