1 files changed, 62 insertions, 0 deletions
diff --git a/pl/math/v_atanhf_3u1.c b/pl/math/v_atanhf_3u1.c
new file mode 100644
index 0000000..cd30696
--- /dev/null
+++ b/pl/math/v_atanhf_3u1.c
@@ -0,0 +1,62 @@
+/*
+ * Single-precision vector atanh(x) function.
+ *
+ * Copyright (c) 2022-2023, Arm Limited.
+ * SPDX-License-Identifier: MIT OR Apache-2.0 WITH LLVM-exception
+ */
+
+#include "v_math.h"
+#include "mathlib.h"
+#include "pl_sig.h"
+#include "pl_test.h"
+
+#if V_SUPPORTED
+
+#include "v_log1pf_inline.h"
+
+#define AbsMask 0x7fffffff
+#define Half 0x3f000000
+#define One 0x3f800000
+#define TinyBound 0x39800000 /* 0x1p-12, below which atanhf(x) rounds to x. */
+
+/* Approximation for vector single-precision atanh(x) using modified log1p.
+   The maximum error is 3.08 ULP:
+   __v_atanhf(0x1.ff215p-5) got 0x1.ffcb7cp-5
+			   want 0x1.ffcb82p-5.  */
+VPCS_ATTR v_f32_t V_NAME (atanhf) (v_f32_t x)
+{
+  v_u32_t ix = v_as_u32_f32 (x);
+  v_f32_t halfsign
+    = v_as_f32_u32 (v_bsl_u32 (v_u32 (AbsMask), v_u32 (Half), ix));
+  v_u32_t iax = ix & AbsMask;
+
+  v_f32_t ax = v_as_f32_u32 (iax);
+
+#if WANT_SIMD_EXCEPT
+  v_u32_t special = v_cond_u32 ((iax >= One) | (iax <= TinyBound));
+  /* Side-step special cases by setting those lanes to 0, which will trigger no
+     exceptions. These will be fixed up later.  */
+  if (unlikely (v_any_u32 (special)))
+    ax = v_sel_f32 (special, v_f32 (0), ax);
+#else
+  v_u32_t special = v_cond_u32 (iax >= One);
+#endif
+
+  v_f32_t y = halfsign * log1pf_inline ((2 * ax) / (1 - ax));
+
+  if (unlikely (v_any_u32 (special)))
+    return v_call_f32 (atanhf, x, y, special);
+  return y;
+}
+VPCS_ALIAS
+
+PL_SIG (V, F, 1, atanh, -1.0, 1.0)
+PL_TEST_ULP (V_NAME (atanhf), 2.59)
+PL_TEST_EXPECT_FENV (V_NAME (atanhf), WANT_SIMD_EXCEPT)
+PL_TEST_INTERVAL_C (V_NAME (atanhf), 0, 0x1p-12, 500, 0)
+PL_TEST_INTERVAL_C (V_NAME (atanhf), 0x1p-12, 1, 200000, 0)
+PL_TEST_INTERVAL_C (V_NAME (atanhf), 1, inf, 1000, 0)
+PL_TEST_INTERVAL_C (V_NAME (atanhf), -0, -0x1p-12, 500, 0)
+PL_TEST_INTERVAL_C (V_NAME (atanhf), -0x1p-12, -1, 200000, 0)
+PL_TEST_INTERVAL_C (V_NAME (atanhf), -1, -inf, 1000, 0)
+#endif