1 files changed, 75 insertions, 0 deletions
diff --git a/sysdeps/aarch64/fpu/exp2f_sve.c b/sysdeps/aarch64/fpu/exp2f_sve.c
new file mode 100644
index 0000000000..88d10daefc
--- /dev/null
+++ b/sysdeps/aarch64/fpu/exp2f_sve.c
@@ -0,0 +1,75 @@
+/* Single-precision vector (SVE) exp2 function
+
+   Copyright (C) 2023 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include "sv_math.h"
+#include "poly_sve_f32.h"
+
+static const struct data
+{
+  float poly[5];
+  float shift, thres;
+} data = {
+  /* Coefficients copied from the polynomial in AdvSIMD variant, reversed for
+     compatibility with polynomial helpers.  */
+  .poly = { 0x1.62e422p-1f, 0x1.ebf9bcp-3f, 0x1.c6bd32p-5f, 0x1.3ce9e4p-7f,
+	    0x1.59977ap-10f },
+  /* 1.5*2^17 + 127.  */
+  .shift = 0x1.903f8p17f,
+  /* Roughly 87.3. For x < -Thres, the result is subnormal and not handled
+     correctly by FEXPA.  */
+  .thres = 0x1.5d5e2ap+6f,
+};
+
+static svfloat32_t NOINLINE
+special_case (svfloat32_t x, svfloat32_t y, svbool_t special)
+{
+  return sv_call_f32 (exp2f, x, y, special);
+}
+
+/* Single-precision SVE exp2f routine. Implements the same algorithm
+   as AdvSIMD exp2f.
+   Worst case error is 1.04 ULPs.
+   SV_NAME_F1 (exp2)(0x1.943b9p-1) got 0x1.ba7eb2p+0
+				  want 0x1.ba7ebp+0.  */
+svfloat32_t SV_NAME_F1 (exp2) (svfloat32_t x, const svbool_t pg)
+{
+  const struct data *d = ptr_barrier (&data);
+  /* exp2(x) = 2^n (1 + poly(r)), with 1 + poly(r) in [1/sqrt(2),sqrt(2)]
+    x = n + r, with r in [-1/2, 1/2].  */
+  svfloat32_t shift = sv_f32 (d->shift);
+  svfloat32_t z = svadd_x (pg, x, shift);
+  svfloat32_t n = svsub_x (pg, z, shift);
+  svfloat32_t r = svsub_x (pg, x, n);
+
+  svbool_t special = svacgt (pg, x, d->thres);
+  svfloat32_t scale = svexpa (svreinterpret_u32 (z));
+
+  /* Polynomial evaluation: poly(r) ~ exp2(r)-1.
+     Evaluate polynomial use hybrid scheme - offset ESTRIN by 1 for
+     coefficients 1 to 4, and apply most significant coefficient directly.  */
+  svfloat32_t r2 = svmul_x (pg, r, r);
+  svfloat32_t p14 = sv_pairwise_poly_3_f32_x (pg, r, r2, d->poly + 1);
+  svfloat32_t p0 = svmul_x (pg, r, d->poly[0]);
+  svfloat32_t poly = svmla_x (pg, p0, r2, p14);
+
+  if (__glibc_unlikely (svptest_any (pg, special)))
+    return special_case (x, svmla_x (pg, scale, scale, poly), special);
+
+  return svmla_x (pg, scale, scale, poly);
+}