Files
addr2line
adler
adler32
ahash
aho_corasick
angle
approx
backtrace
bitflags
blender
bytemuck
byteorder
case
cast_trait
cfg_if
chrono
color
color_quant
const_fn
crc32fast
crossbeam
crossbeam_channel
crossbeam_deque
crossbeam_epoch
crossbeam_queue
crossbeam_skiplist
crossbeam_utils
darling
darling_core
darling_macro
dds
deflate
densevec
derive_builder
derive_builder_core
dot
downcast_rs
dual_quat
either
erased_serde
failure
failure_derive
fixedbitset
float_cmp
fnv
freeimage
freeimage_sys
freetype
freetype_gl_sys
freetype_sys
freetypegl
futures
futures_channel
futures_core
futures_executor
futures_io
futures_macro
futures_sink
futures_task
futures_util
async_await
future
io
lock
sink
stream
task
fxhash
generational_arena
generic_array
getrandom
gif
gimli
glfw
glfw_sys
glin
glin_derive
glsl
half
harfbuzz
harfbuzz_ft_sys
harfbuzz_sys
hashbrown
human_sort
ident_case
image
indexmap
instant
itertools
itoa
jpeg_decoder
lazy_static
libc
libm
lock_api
log
lut_parser
matrixmultiply
memchr
memoffset
meshopt
miniz_oxide
monotonic_clock
mopa
mutiny_derive
na
nalgebra
base
geometry
linalg
ncollide3d
bounding_volume
interpolation
partitioning
pipeline
procedural
query
algorithms
closest_points
contact
distance
nonlinear_time_of_impact
point
proximity
ray
time_of_impact
visitors
shape
transformation
utils
nom
num_complex
num_cpus
num_integer
num_iter
num_rational
num_traits
numext_constructor
numext_fixed_uint
numext_fixed_uint_core
numext_fixed_uint_hack
object
once_cell
parking_lot
parking_lot_core
pathfinding
pennereq
petgraph
pin_project_lite
pin_utils
png
polygon2
ppv_lite86
proc_macro2
proc_macro_crate
proc_macro_hack
proc_macro_nested
quote
rand
rand_chacha
rand_core
rand_distr
raw_window_handle
rawpointer
rayon
rayon_core
rect_packer
regex
regex_syntax
retain_mut
rin
rin_app
rin_blender
rin_core
rin_gl
rin_graphics
rin_gui
rin_material
rin_math
rin_postpo
rin_scene
rin_util
rin_window
rinblender
rinecs
rinecs_derive
rinecs_derive_utils
ringui_derive
rustc_demangle
rusty_pool
ryu
scopeguard
seitan
seitan_derive
semver
semver_parser
serde
serde_derive
serde_json
shaderdata_derive
simba
slab
slice_of_array
slotmap
smallvec
std140_data
streaming_iterator
strsim
syn
synstructure
thiserror
thiserror_impl
thread_local
tiff
time
toml
typenum
unchecked_unwrap
unicode_xid
vec2
vec3
weezl
x11
zlib_sys
 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
/* origin: FreeBSD /usr/src/lib/msun/src/e_asinf.c */
/*
 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
 */
/*
 * ====================================================
 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
 *
 * Developed at SunPro, a Sun Microsystems, Inc. business.
 * Permission to use, copy, modify, and distribute this
 * software is freely granted, provided that this notice
 * is preserved.
 * ====================================================
 */

use super::fabsf::fabsf;
use super::sqrt::sqrt;

const PIO2: f64 = 1.570796326794896558e+00;

/* coefficients for R(x^2) */
const P_S0: f32 = 1.6666586697e-01;
const P_S1: f32 = -4.2743422091e-02;
const P_S2: f32 = -8.6563630030e-03;
const Q_S1: f32 = -7.0662963390e-01;

fn r(z: f32) -> f32 {
    let p = z * (P_S0 + z * (P_S1 + z * P_S2));
    let q = 1. + z * Q_S1;
    p / q
}

/// Arcsine (f32)
///
/// Computes the inverse sine (arc sine) of the argument `x`.
/// Arguments to asin must be in the range -1 to 1.
/// Returns values in radians, in the range of -pi/2 to pi/2.
#[cfg_attr(all(test, assert_no_panic), no_panic::no_panic)]
pub fn asinf(mut x: f32) -> f32 {
    let x1p_120 = f64::from_bits(0x3870000000000000); // 0x1p-120 === 2 ^ (-120)

    let hx = x.to_bits();
    let ix = hx & 0x7fffffff;

    if ix >= 0x3f800000 {
        /* |x| >= 1 */
        if ix == 0x3f800000 {
            /* |x| == 1 */
            return ((x as f64) * PIO2 + x1p_120) as f32; /* asin(+-1) = +-pi/2 with inexact */
        }
        return 0. / (x - x); /* asin(|x|>1) is NaN */
    }

    if ix < 0x3f000000 {
        /* |x| < 0.5 */
        /* if 0x1p-126 <= |x| < 0x1p-12, avoid raising underflow */
        if (ix < 0x39800000) && (ix >= 0x00800000) {
            return x;
        }
        return x + x * r(x * x);
    }

    /* 1 > |x| >= 0.5 */
    let z = (1. - fabsf(x)) * 0.5;
    let s = sqrt(z as f64);
    x = (PIO2 - 2. * (s + s * (r(z) as f64))) as f32;
    if (hx >> 31) != 0 {
        -x
    } else {
        x
    }
}