pl/math: Add scalar asinhf

asinhf depends on logf, which has been copied over from the main math
directory. The only modification was to change the name logf to
optr_aor_log_f32 to resolve any ambiguity with libm.

Worst-case error is about 3.4 ULP, at very large input. There are 4
intervals with slightly different error behaviour, as follows:

Interval              Worst-case accuracy (ulp)
|x| < 2^-12           0
|x| < 1               1.3
|x| < sqrt(FLT_MAX)   2.0
|x| < infinity        3.4

1 files changed, 29 insertions, 0 deletions

diff --git a/pl/math/tools/asinhf.sollya b/pl/math/tools/asinhf.sollya
new file mode 100644
index 0000000..cbe7d62
--- /dev/null
+++ b/pl/math/tools/asinhf.sollya
@@ -0,0 +1,29 @@
+// polynomial for approximating asinh(x)
+//
+// Copyright (c) 2022, Arm Limited.
+// SPDX-License-Identifier: MIT OR Apache-2.0 WITH LLVM-exception
+
+deg = 9;
+
+a = 0x1.0p-12;
+b = 1.0;
+
+f = proc(y) {
+  return asinh(x);
+};
+
+approx = proc(poly, d) {
+  return remez(1 - poly(x)/f(x), deg-d, [a;b], x^d/f(x), 1e-10);
+};
+
+poly = x;
+for i from 2 to deg do {
+  p = roundcoefficients(approx(poly,i), [|SG ...|]);
+  poly = poly + x^i*coeff(p,0);
+};
+
+display = hexadecimal;
+print("rel error:", accurateinfnorm(1-poly(x)/f(x), [a;b], 30));
+print("in [",a,b,"]");
+print("coeffs:");
+for i from 2 to deg do coeff(poly,i);