flatten lib/std/special and improve "pkg inside another" logic

stage2: change logic for detecting whether the main package is inside
the std package. Previously it relied on realpath() which is not portable.
This uses resolve() which is how imports already work.

 * stage2: fix cleanup bug when creating Module
 * flatten lib/std/special/* to lib/*
   - this was motivated by making main_pkg_is_inside_std false for
     compiler_rt & friends.
 * rename "mini libc" to "universal libc"

1 files changed, 461 insertions, 0 deletions

diff --git a/lib/compiler_rt/exp2.zig b/lib/compiler_rt/exp2.zig
new file mode 100644
index 0000000000..53432a831d
--- /dev/null
+++ b/lib/compiler_rt/exp2.zig
@@ -0,0 +1,461 @@
+// Ported from musl, which is licensed under the MIT license:
+// https://git.musl-libc.org/cgit/musl/tree/COPYRIGHT
+//
+// https://git.musl-libc.org/cgit/musl/tree/src/math/exp2f.c
+// https://git.musl-libc.org/cgit/musl/tree/src/math/exp2.c
+
+const std = @import("std");
+const math = std.math;
+const expect = std.testing.expect;
+
+pub fn __exp2h(x: f16) callconv(.C) f16 {
+    // TODO: more efficient implementation
+    return @floatCast(f16, exp2f(x));
+}
+
+pub fn exp2f(x: f32) callconv(.C) f32 {
+    const tblsiz = @intCast(u32, exp2ft.len);
+    const redux: f32 = 0x1.8p23 / @intToFloat(f32, tblsiz);
+    const P1: f32 = 0x1.62e430p-1;
+    const P2: f32 = 0x1.ebfbe0p-3;
+    const P3: f32 = 0x1.c6b348p-5;
+    const P4: f32 = 0x1.3b2c9cp-7;
+
+    var u = @bitCast(u32, x);
+    const ix = u & 0x7FFFFFFF;
+
+    // |x| > 126
+    if (ix > 0x42FC0000) {
+        // nan
+        if (ix > 0x7F800000) {
+            return x;
+        }
+        // x >= 128
+        if (u >= 0x43000000 and u < 0x80000000) {
+            return x * 0x1.0p127;
+        }
+        // x < -126
+        if (u >= 0x80000000) {
+            if (u >= 0xC3160000 or u & 0x000FFFF != 0) {
+                math.doNotOptimizeAway(-0x1.0p-149 / x);
+            }
+            // x <= -150
+            if (u >= 0x3160000) {
+                return 0;
+            }
+        }
+    }
+    // |x| <= 0x1p-25
+    else if (ix <= 0x33000000) {
+        return 1.0 + x;
+    }
+
+    // NOTE: musl relies on unsafe behaviours which are replicated below
+    // (addition/bit-shift overflow). Appears that this produces the
+    // intended result but should confirm how GCC/Clang handle this to ensure.
+
+    var uf = x + redux;
+    var i_0 = @bitCast(u32, uf);
+    i_0 +%= tblsiz / 2;
+
+    const k = i_0 / tblsiz;
+    const uk = @bitCast(f64, @as(u64, 0x3FF + k) << 52);
+    i_0 &= tblsiz - 1;
+    uf -= redux;
+
+    const z: f64 = x - uf;
+    var r: f64 = exp2ft[@intCast(usize, i_0)];
+    const t: f64 = r * z;
+    r = r + t * (P1 + z * P2) + t * (z * z) * (P3 + z * P4);
+    return @floatCast(f32, r * uk);
+}
+
+pub fn exp2(x: f64) callconv(.C) f64 {
+    const tblsiz: u32 = @intCast(u32, exp2dt.len / 2);
+    const redux: f64 = 0x1.8p52 / @intToFloat(f64, tblsiz);
+    const P1: f64 = 0x1.62e42fefa39efp-1;
+    const P2: f64 = 0x1.ebfbdff82c575p-3;
+    const P3: f64 = 0x1.c6b08d704a0a6p-5;
+    const P4: f64 = 0x1.3b2ab88f70400p-7;
+    const P5: f64 = 0x1.5d88003875c74p-10;
+
+    const ux = @bitCast(u64, x);
+    const ix = @intCast(u32, ux >> 32) & 0x7FFFFFFF;
+
+    // TODO: This should be handled beneath.
+    if (math.isNan(x)) {
+        return math.nan(f64);
+    }
+
+    // |x| >= 1022 or nan
+    if (ix >= 0x408FF000) {
+        // x >= 1024 or nan
+        if (ix >= 0x40900000 and ux >> 63 == 0) {
+            math.raiseOverflow();
+            return math.inf(f64);
+        }
+        // -inf or -nan
+        if (ix >= 0x7FF00000) {
+            return -1 / x;
+        }
+        // x <= -1022
+        if (ux >> 63 != 0) {
+            // underflow
+            if (x <= -1075 or x - 0x1.0p52 + 0x1.0p52 != x) {
+                math.doNotOptimizeAway(@floatCast(f32, -0x1.0p-149 / x));
+            }
+            if (x <= -1075) {
+                return 0;
+            }
+        }
+    }
+    // |x| < 0x1p-54
+    else if (ix < 0x3C900000) {
+        return 1.0 + x;
+    }
+
+    // NOTE: musl relies on unsafe behaviours which are replicated below
+    // (addition overflow, division truncation, casting). Appears that this
+    // produces the intended result but should confirm how GCC/Clang handle this
+    // to ensure.
+
+    // reduce x
+    var uf: f64 = x + redux;
+    // NOTE: musl performs an implicit 64-bit to 32-bit u32 truncation here
+    var i_0: u32 = @truncate(u32, @bitCast(u64, uf));
+    i_0 +%= tblsiz / 2;
+
+    const k: u32 = i_0 / tblsiz * tblsiz;
+    const ik: i32 = @divTrunc(@bitCast(i32, k), tblsiz);
+    i_0 %= tblsiz;
+    uf -= redux;
+
+    // r = exp2(y) = exp2t[i_0] * p(z - eps[i])
+    var z: f64 = x - uf;
+    const t: f64 = exp2dt[@intCast(usize, 2 * i_0)];
+    z -= exp2dt[@intCast(usize, 2 * i_0 + 1)];
+    const r: f64 = t + t * z * (P1 + z * (P2 + z * (P3 + z * (P4 + z * P5))));
+
+    return math.scalbn(r, ik);
+}
+
+pub fn __exp2x(x: f80) callconv(.C) f80 {
+    // TODO: more efficient implementation
+    return @floatCast(f80, exp2q(x));
+}
+
+pub fn exp2q(x: f128) callconv(.C) f128 {
+    // TODO: more correct implementation
+    return exp2(@floatCast(f64, x));
+}
+
+const exp2ft = [_]f64{
+    0x1.6a09e667f3bcdp-1,
+    0x1.7a11473eb0187p-1,
+    0x1.8ace5422aa0dbp-1,
+    0x1.9c49182a3f090p-1,
+    0x1.ae89f995ad3adp-1,
+    0x1.c199bdd85529cp-1,
+    0x1.d5818dcfba487p-1,
+    0x1.ea4afa2a490dap-1,
+    0x1.0000000000000p+0,
+    0x1.0b5586cf9890fp+0,
+    0x1.172b83c7d517bp+0,
+    0x1.2387a6e756238p+0,
+    0x1.306fe0a31b715p+0,
+    0x1.3dea64c123422p+0,
+    0x1.4bfdad5362a27p+0,
+    0x1.5ab07dd485429p+0,
+};
+
+const exp2dt = [_]f64{
+    //  exp2(z + eps)          eps
+    0x1.6a09e667f3d5dp-1, 0x1.9880p-44,
+    0x1.6b052fa751744p-1, 0x1.8000p-50,
+    0x1.6c012750bd9fep-1, -0x1.8780p-45,
+    0x1.6cfdcddd476bfp-1, 0x1.ec00p-46,
+    0x1.6dfb23c651a29p-1, -0x1.8000p-50,
+    0x1.6ef9298593ae3p-1, -0x1.c000p-52,
+    0x1.6ff7df9519386p-1, -0x1.fd80p-45,
+    0x1.70f7466f42da3p-1, -0x1.c880p-45,
+    0x1.71f75e8ec5fc3p-1, 0x1.3c00p-46,
+    0x1.72f8286eacf05p-1, -0x1.8300p-44,
+    0x1.73f9a48a58152p-1, -0x1.0c00p-47,
+    0x1.74fbd35d7ccfcp-1, 0x1.f880p-45,
+    0x1.75feb564267f1p-1, 0x1.3e00p-47,
+    0x1.77024b1ab6d48p-1, -0x1.7d00p-45,
+    0x1.780694fde5d38p-1, -0x1.d000p-50,
+    0x1.790b938ac1d00p-1, 0x1.3000p-49,
+    0x1.7a11473eb0178p-1, -0x1.d000p-49,
+    0x1.7b17b0976d060p-1, 0x1.0400p-45,
+    0x1.7c1ed0130c133p-1, 0x1.0000p-53,
+    0x1.7d26a62ff8636p-1, -0x1.6900p-45,
+    0x1.7e2f336cf4e3bp-1, -0x1.2e00p-47,
+    0x1.7f3878491c3e8p-1, -0x1.4580p-45,
+    0x1.80427543e1b4ep-1, 0x1.3000p-44,
+    0x1.814d2add1071ap-1, 0x1.f000p-47,
+    0x1.82589994ccd7ep-1, -0x1.1c00p-45,
+    0x1.8364c1eb942d0p-1, 0x1.9d00p-45,
+    0x1.8471a4623cab5p-1, 0x1.7100p-43,
+    0x1.857f4179f5bbcp-1, 0x1.2600p-45,
+    0x1.868d99b4491afp-1, -0x1.2c40p-44,
+    0x1.879cad931a395p-1, -0x1.3000p-45,
+    0x1.88ac7d98a65b8p-1, -0x1.a800p-45,
+    0x1.89bd0a4785800p-1, -0x1.d000p-49,
+    0x1.8ace5422aa223p-1, 0x1.3280p-44,
+    0x1.8be05bad619fap-1, 0x1.2b40p-43,
+    0x1.8cf3216b54383p-1, -0x1.ed00p-45,
+    0x1.8e06a5e08664cp-1, -0x1.0500p-45,
+    0x1.8f1ae99157807p-1, 0x1.8280p-45,
+    0x1.902fed0282c0ep-1, -0x1.cb00p-46,
+    0x1.9145b0b91ff96p-1, -0x1.5e00p-47,
+    0x1.925c353aa2ff9p-1, 0x1.5400p-48,
+    0x1.93737b0cdc64ap-1, 0x1.7200p-46,
+    0x1.948b82b5f98aep-1, -0x1.9000p-47,
+    0x1.95a44cbc852cbp-1, 0x1.5680p-45,
+    0x1.96bdd9a766f21p-1, -0x1.6d00p-44,
+    0x1.97d829fde4e2ap-1, -0x1.1000p-47,
+    0x1.98f33e47a23a3p-1, 0x1.d000p-45,
+    0x1.9a0f170ca0604p-1, -0x1.8a40p-44,
+    0x1.9b2bb4d53ff89p-1, 0x1.55c0p-44,
+    0x1.9c49182a3f15bp-1, 0x1.6b80p-45,
+    0x1.9d674194bb8c5p-1, -0x1.c000p-49,
+    0x1.9e86319e3238ep-1, 0x1.7d00p-46,
+    0x1.9fa5e8d07f302p-1, 0x1.6400p-46,
+    0x1.a0c667b5de54dp-1, -0x1.5000p-48,
+    0x1.a1e7aed8eb8f6p-1, 0x1.9e00p-47,
+    0x1.a309bec4a2e27p-1, 0x1.ad80p-45,
+    0x1.a42c980460a5dp-1, -0x1.af00p-46,
+    0x1.a5503b23e259bp-1, 0x1.b600p-47,
+    0x1.a674a8af46213p-1, 0x1.8880p-44,
+    0x1.a799e1330b3a7p-1, 0x1.1200p-46,
+    0x1.a8bfe53c12e8dp-1, 0x1.6c00p-47,
+    0x1.a9e6b5579fcd2p-1, -0x1.9b80p-45,
+    0x1.ab0e521356fb8p-1, 0x1.b700p-45,
+    0x1.ac36bbfd3f381p-1, 0x1.9000p-50,
+    0x1.ad5ff3a3c2780p-1, 0x1.4000p-49,
+    0x1.ae89f995ad2a3p-1, -0x1.c900p-45,
+    0x1.afb4ce622f367p-1, 0x1.6500p-46,
+    0x1.b0e07298db790p-1, 0x1.fd40p-45,
+    0x1.b20ce6c9a89a9p-1, 0x1.2700p-46,
+    0x1.b33a2b84f1a4bp-1, 0x1.d470p-43,
+    0x1.b468415b747e7p-1, -0x1.8380p-44,
+    0x1.b59728de5593ap-1, 0x1.8000p-54,
+    0x1.b6c6e29f1c56ap-1, 0x1.ad00p-47,
+    0x1.b7f76f2fb5e50p-1, 0x1.e800p-50,
+    0x1.b928cf22749b2p-1, -0x1.4c00p-47,
+    0x1.ba5b030a10603p-1, -0x1.d700p-47,
+    0x1.bb8e0b79a6f66p-1, 0x1.d900p-47,
+    0x1.bcc1e904bc1ffp-1, 0x1.2a00p-47,
+    0x1.bdf69c3f3a16fp-1, -0x1.f780p-46,
+    0x1.bf2c25bd71db8p-1, -0x1.0a00p-46,
+    0x1.c06286141b2e9p-1, -0x1.1400p-46,
+    0x1.c199bdd8552e0p-1, 0x1.be00p-47,
+    0x1.c2d1cd9fa64eep-1, -0x1.9400p-47,
+    0x1.c40ab5fffd02fp-1, -0x1.ed00p-47,
+    0x1.c544778fafd15p-1, 0x1.9660p-44,
+    0x1.c67f12e57d0cbp-1, -0x1.a100p-46,
+    0x1.c7ba88988c1b6p-1, -0x1.8458p-42,
+    0x1.c8f6d9406e733p-1, -0x1.a480p-46,
+    0x1.ca3405751c4dfp-1, 0x1.b000p-51,
+    0x1.cb720dcef9094p-1, 0x1.1400p-47,
+    0x1.ccb0f2e6d1689p-1, 0x1.0200p-48,
+    0x1.cdf0b555dc412p-1, 0x1.3600p-48,
+    0x1.cf3155b5bab3bp-1, -0x1.6900p-47,
+    0x1.d072d4a0789bcp-1, 0x1.9a00p-47,
+    0x1.d1b532b08c8fap-1, -0x1.5e00p-46,
+    0x1.d2f87080d8a85p-1, 0x1.d280p-46,
+    0x1.d43c8eacaa203p-1, 0x1.1a00p-47,
+    0x1.d5818dcfba491p-1, 0x1.f000p-50,
+    0x1.d6c76e862e6a1p-1, -0x1.3a00p-47,
+    0x1.d80e316c9834ep-1, -0x1.cd80p-47,
+    0x1.d955d71ff6090p-1, 0x1.4c00p-48,
+    0x1.da9e603db32aep-1, 0x1.f900p-48,
+    0x1.dbe7cd63a8325p-1, 0x1.9800p-49,
+    0x1.dd321f301b445p-1, -0x1.5200p-48,
+    0x1.de7d5641c05bfp-1, -0x1.d700p-46,
+    0x1.dfc97337b9aecp-1, -0x1.6140p-46,
+    0x1.e11676b197d5ep-1, 0x1.b480p-47,
+    0x1.e264614f5a3e7p-1, 0x1.0ce0p-43,
+    0x1.e3b333b16ee5cp-1, 0x1.c680p-47,
+    0x1.e502ee78b3fb4p-1, -0x1.9300p-47,
+    0x1.e653924676d68p-1, -0x1.5000p-49,
+    0x1.e7a51fbc74c44p-1, -0x1.7f80p-47,
+    0x1.e8f7977cdb726p-1, -0x1.3700p-48,
+    0x1.ea4afa2a490e8p-1, 0x1.5d00p-49,
+    0x1.eb9f4867ccae4p-1, 0x1.61a0p-46,
+    0x1.ecf482d8e680dp-1, 0x1.5500p-48,
+    0x1.ee4aaa2188514p-1, 0x1.6400p-51,
+    0x1.efa1bee615a13p-1, -0x1.e800p-49,
+    0x1.f0f9c1cb64106p-1, -0x1.a880p-48,
+    0x1.f252b376bb963p-1, -0x1.c900p-45,
+    0x1.f3ac948dd7275p-1, 0x1.a000p-53,
+    0x1.f50765b6e4524p-1, -0x1.4f00p-48,
+    0x1.f6632798844fdp-1, 0x1.a800p-51,
+    0x1.f7bfdad9cbe38p-1, 0x1.abc0p-48,
+    0x1.f91d802243c82p-1, -0x1.4600p-50,
+    0x1.fa7c1819e908ep-1, -0x1.b0c0p-47,
+    0x1.fbdba3692d511p-1, -0x1.0e00p-51,
+    0x1.fd3c22b8f7194p-1, -0x1.0de8p-46,
+    0x1.fe9d96b2a23eep-1, 0x1.e430p-49,
+    0x1.0000000000000p+0, 0x0.0000p+0,
+    0x1.00b1afa5abcbep+0, -0x1.3400p-52,
+    0x1.0163da9fb3303p+0, -0x1.2170p-46,
+    0x1.02168143b0282p+0, 0x1.a400p-52,
+    0x1.02c9a3e77806cp+0, 0x1.f980p-49,
+    0x1.037d42e11bbcap+0, -0x1.7400p-51,
+    0x1.04315e86e7f89p+0, 0x1.8300p-50,
+    0x1.04e5f72f65467p+0, -0x1.a3f0p-46,
+    0x1.059b0d315855ap+0, -0x1.2840p-47,
+    0x1.0650a0e3c1f95p+0, 0x1.1600p-48,
+    0x1.0706b29ddf71ap+0, 0x1.5240p-46,
+    0x1.07bd42b72a82dp+0, -0x1.9a00p-49,
+    0x1.0874518759bd0p+0, 0x1.6400p-49,
+    0x1.092bdf66607c8p+0, -0x1.0780p-47,
+    0x1.09e3ecac6f383p+0, -0x1.8000p-54,
+    0x1.0a9c79b1f3930p+0, 0x1.fa00p-48,
+    0x1.0b5586cf988fcp+0, -0x1.ac80p-48,
+    0x1.0c0f145e46c8ap+0, 0x1.9c00p-50,
+    0x1.0cc922b724816p+0, 0x1.5200p-47,
+    0x1.0d83b23395dd8p+0, -0x1.ad00p-48,
+    0x1.0e3ec32d3d1f3p+0, 0x1.bac0p-46,
+    0x1.0efa55fdfa9a6p+0, -0x1.4e80p-47,
+    0x1.0fb66affed2f0p+0, -0x1.d300p-47,
+    0x1.1073028d7234bp+0, 0x1.1500p-48,
+    0x1.11301d0125b5bp+0, 0x1.c000p-49,
+    0x1.11edbab5e2af9p+0, 0x1.6bc0p-46,
+    0x1.12abdc06c31d5p+0, 0x1.8400p-49,
+    0x1.136a814f2047dp+0, -0x1.ed00p-47,
+    0x1.1429aaea92de9p+0, 0x1.8e00p-49,
+    0x1.14e95934f3138p+0, 0x1.b400p-49,
+    0x1.15a98c8a58e71p+0, 0x1.5300p-47,
+    0x1.166a45471c3dfp+0, 0x1.3380p-47,
+    0x1.172b83c7d5211p+0, 0x1.8d40p-45,
+    0x1.17ed48695bb9fp+0, -0x1.5d00p-47,
+    0x1.18af9388c8d93p+0, -0x1.c880p-46,
+    0x1.1972658375d66p+0, 0x1.1f00p-46,
+    0x1.1a35beb6fcba7p+0, 0x1.0480p-46,
+    0x1.1af99f81387e3p+0, -0x1.7390p-43,
+    0x1.1bbe084045d54p+0, 0x1.4e40p-45,
+    0x1.1c82f95281c43p+0, -0x1.a200p-47,
+    0x1.1d4873168b9b2p+0, 0x1.3800p-49,
+    0x1.1e0e75eb44031p+0, 0x1.ac00p-49,
+    0x1.1ed5022fcd938p+0, 0x1.1900p-47,
+    0x1.1f9c18438cdf7p+0, -0x1.b780p-46,
+    0x1.2063b88628d8fp+0, 0x1.d940p-45,
+    0x1.212be3578a81ep+0, 0x1.8000p-50,
+    0x1.21f49917ddd41p+0, 0x1.b340p-45,
+    0x1.22bdda2791323p+0, 0x1.9f80p-46,
+    0x1.2387a6e7561e7p+0, -0x1.9c80p-46,
+    0x1.2451ffb821427p+0, 0x1.2300p-47,
+    0x1.251ce4fb2a602p+0, -0x1.3480p-46,
+    0x1.25e85711eceb0p+0, 0x1.2700p-46,
+    0x1.26b4565e27d16p+0, 0x1.1d00p-46,
+    0x1.2780e341de00fp+0, 0x1.1ee0p-44,
+    0x1.284dfe1f5633ep+0, -0x1.4c00p-46,
+    0x1.291ba7591bb30p+0, -0x1.3d80p-46,
+    0x1.29e9df51fdf09p+0, 0x1.8b00p-47,
+    0x1.2ab8a66d10e9bp+0, -0x1.27c0p-45,
+    0x1.2b87fd0dada3ap+0, 0x1.a340p-45,
+    0x1.2c57e39771af9p+0, -0x1.0800p-46,
+    0x1.2d285a6e402d9p+0, -0x1.ed00p-47,
+    0x1.2df961f641579p+0, -0x1.4200p-48,
+    0x1.2ecafa93e2ecfp+0, -0x1.4980p-45,
+    0x1.2f9d24abd8822p+0, -0x1.6300p-46,
+    0x1.306fe0a31b625p+0, -0x1.2360p-44,
+    0x1.31432edeea50bp+0, -0x1.0df8p-40,
+    0x1.32170fc4cd7b8p+0, -0x1.2480p-45,
+    0x1.32eb83ba8e9a2p+0, -0x1.5980p-45,
+    0x1.33c08b2641766p+0, 0x1.ed00p-46,
+    0x1.3496266e3fa27p+0, -0x1.c000p-50,
+    0x1.356c55f929f0fp+0, -0x1.0d80p-44,
+    0x1.36431a2de88b9p+0, 0x1.2c80p-45,
+    0x1.371a7373aaa39p+0, 0x1.0600p-45,
+    0x1.37f26231e74fep+0, -0x1.6600p-46,
+    0x1.38cae6d05d838p+0, -0x1.ae00p-47,
+    0x1.39a401b713ec3p+0, -0x1.4720p-43,
+    0x1.3a7db34e5a020p+0, 0x1.8200p-47,
+    0x1.3b57fbfec6e95p+0, 0x1.e800p-44,
+    0x1.3c32dc313a8f2p+0, 0x1.f800p-49,
+    0x1.3d0e544ede122p+0, -0x1.7a00p-46,
+    0x1.3dea64c1234bbp+0, 0x1.6300p-45,
+    0x1.3ec70df1c4eccp+0, -0x1.8a60p-43,
+    0x1.3fa4504ac7e8cp+0, -0x1.cdc0p-44,
+    0x1.40822c367a0bbp+0, 0x1.5b80p-45,
+    0x1.4160a21f72e95p+0, 0x1.ec00p-46,
+    0x1.423fb27094646p+0, -0x1.3600p-46,
+    0x1.431f5d950a920p+0, 0x1.3980p-45,
+    0x1.43ffa3f84b9ebp+0, 0x1.a000p-48,
+    0x1.44e0860618919p+0, -0x1.6c00p-48,
+    0x1.45c2042a7d201p+0, -0x1.bc00p-47,
+    0x1.46a41ed1d0016p+0, -0x1.2800p-46,
+    0x1.4786d668b3326p+0, 0x1.0e00p-44,
+    0x1.486a2b5c13c00p+0, -0x1.d400p-45,
+    0x1.494e1e192af04p+0, 0x1.c200p-47,
+    0x1.4a32af0d7d372p+0, -0x1.e500p-46,
+    0x1.4b17dea6db801p+0, 0x1.7800p-47,
+    0x1.4bfdad53629e1p+0, -0x1.3800p-46,
+    0x1.4ce41b817c132p+0, 0x1.0800p-47,
+    0x1.4dcb299fddddbp+0, 0x1.c700p-45,
+    0x1.4eb2d81d8ab96p+0, -0x1.ce00p-46,
+    0x1.4f9b2769d2d02p+0, 0x1.9200p-46,
+    0x1.508417f4531c1p+0, -0x1.8c00p-47,
+    0x1.516daa2cf662ap+0, -0x1.a000p-48,
+    0x1.5257de83f51eap+0, 0x1.a080p-43,
+    0x1.5342b569d4edap+0, -0x1.6d80p-45,
+    0x1.542e2f4f6ac1ap+0, -0x1.2440p-44,
+    0x1.551a4ca5d94dbp+0, 0x1.83c0p-43,
+    0x1.56070dde9116bp+0, 0x1.4b00p-45,
+    0x1.56f4736b529dep+0, 0x1.15a0p-43,
+    0x1.57e27dbe2c40ep+0, -0x1.9e00p-45,
+    0x1.58d12d497c76fp+0, -0x1.3080p-45,
+    0x1.59c0827ff0b4cp+0, 0x1.dec0p-43,
+    0x1.5ab07dd485427p+0, -0x1.4000p-51,
+    0x1.5ba11fba87af4p+0, 0x1.0080p-44,
+    0x1.5c9268a59460bp+0, -0x1.6c80p-45,
+    0x1.5d84590998e3fp+0, 0x1.69a0p-43,
+    0x1.5e76f15ad20e1p+0, -0x1.b400p-46,
+    0x1.5f6a320dcebcap+0, 0x1.7700p-46,
+    0x1.605e1b976dcb8p+0, 0x1.6f80p-45,
+    0x1.6152ae6cdf715p+0, 0x1.1000p-47,
+    0x1.6247eb03a5531p+0, -0x1.5d00p-46,
+    0x1.633dd1d1929b5p+0, -0x1.2d00p-46,
+    0x1.6434634ccc313p+0, -0x1.a800p-49,
+    0x1.652b9febc8efap+0, -0x1.8600p-45,
+    0x1.6623882553397p+0, 0x1.1fe0p-40,
+    0x1.671c1c708328ep+0, -0x1.7200p-44,
+    0x1.68155d44ca97ep+0, 0x1.6800p-49,
+    0x1.690f4b19e9471p+0, -0x1.9780p-45,
+};
+
+test "exp2_32" {
+    const epsilon = 0.000001;
+
+    try expect(exp2f(0.0) == 1.0);
+    try expect(math.approxEqAbs(f32, exp2f(0.2), 1.148698, epsilon));
+    try expect(math.approxEqAbs(f32, exp2f(0.8923), 1.856133, epsilon));
+    try expect(math.approxEqAbs(f32, exp2f(1.5), 2.828427, epsilon));
+    try expect(math.approxEqAbs(f32, exp2f(37.45), 187747237888, epsilon));
+    try expect(math.approxEqAbs(f32, exp2f(-1), 0.5, epsilon));
+}
+
+test "exp2_64" {
+    const epsilon = 0.000001;
+
+    try expect(exp2(0.0) == 1.0);
+    try expect(math.approxEqAbs(f64, exp2(0.2), 1.148698, epsilon));
+    try expect(math.approxEqAbs(f64, exp2(0.8923), 1.856133, epsilon));
+    try expect(math.approxEqAbs(f64, exp2(1.5), 2.828427, epsilon));
+    try expect(math.approxEqAbs(f64, exp2(-1), 0.5, epsilon));
+    try expect(math.approxEqAbs(f64, exp2(-0x1.a05cc754481d1p-2), 0x1.824056efc687cp-1, epsilon));
+}
+
+test "exp2_32.special" {
+    try expect(math.isPositiveInf(exp2f(math.inf(f32))));
+    try expect(math.isNan(exp2f(math.nan(f32))));
+}
+
+test "exp2_64.special" {
+    try expect(math.isPositiveInf(exp2(math.inf(f64))));
+    try expect(math.isNan(exp2(math.nan(f64))));
+}