1 files changed, 94 insertions, 0 deletions
diff --git a/pl/math/sv_atan2f_3u.c b/pl/math/sv_atan2f_3u.c
new file mode 100644
index 0000000..f7674c4
--- /dev/null
+++ b/pl/math/sv_atan2f_3u.c
@@ -0,0 +1,94 @@
+/*
+ * Single-precision vector atan2f(x) function.
+ *
+ * Copyright (c) 2021-2023, Arm Limited.
+ * SPDX-License-Identifier: MIT OR Apache-2.0 WITH LLVM-exception
+ */
+
+#include "sv_math.h"
+#include "pl_sig.h"
+#include "pl_test.h"
+
+#if SV_SUPPORTED
+
+#include "sv_atanf_common.h"
+
+/* Useful constants.  */
+#define PiOver2 sv_f32 (0x1.921fb6p+0f)
+#define SignMask sv_u32 (0x80000000)
+
+/* Special cases i.e. 0, infinity, nan (fall back to scalar calls).  */
+static inline sv_f32_t
+specialcase (sv_f32_t y, sv_f32_t x, sv_f32_t ret, const svbool_t cmp)
+{
+  return sv_call2_f32 (atan2f, y, x, ret, cmp);
+}
+
+/* Returns a predicate indicating true if the input is the bit representation of
+   0, infinity or nan.  */
+static inline svbool_t
+zeroinfnan (sv_u32_t i, const svbool_t pg)
+{
+  return svcmpge_u32 (pg, svsub_n_u32_x (pg, svlsl_n_u32_x (pg, i, 1), 1),
+		      sv_u32 (2 * 0x7f800000lu - 1));
+}
+
+/* Fast implementation of SVE atan2f based on atan(x) ~ shift + z + z^3 * P(z^2)
+   with reduction to [0,1] using z=1/x and shift = pi/2.
+   Maximum observed error is 2.95 ULP:
+   __sv_atan2f(0x1.93836cp+6, 0x1.8cae1p+6) got 0x1.967f06p-1
+					   want 0x1.967f00p-1.  */
+sv_f32_t
+__sv_atan2f_x (sv_f32_t y, sv_f32_t x, const svbool_t pg)
+{
+  sv_u32_t ix = sv_as_u32_f32 (x);
+  sv_u32_t iy = sv_as_u32_f32 (y);
+
+  svbool_t cmp_x = zeroinfnan (ix, pg);
+  svbool_t cmp_y = zeroinfnan (iy, pg);
+  svbool_t cmp_xy = svorr_b_z (pg, cmp_x, cmp_y);
+
+  sv_u32_t sign_x = svand_u32_x (pg, ix, SignMask);
+  sv_u32_t sign_y = svand_u32_x (pg, iy, SignMask);
+  sv_u32_t sign_xy = sveor_u32_x (pg, sign_x, sign_y);
+
+  sv_f32_t ax = svabs_f32_x (pg, x);
+  sv_f32_t ay = svabs_f32_x (pg, y);
+
+  svbool_t pred_xlt0 = svcmplt_f32 (pg, x, sv_f32 (0.0));
+  svbool_t pred_aygtax = svcmpgt_f32 (pg, ay, ax);
+
+  /* Set up z for call to atan.  */
+  sv_f32_t n = svsel_f32 (pred_aygtax, svneg_f32_x (pg, ax), ay);
+  sv_f32_t d = svsel_f32 (pred_aygtax, ay, ax);
+  sv_f32_t z = svdiv_f32_x (pg, n, d);
+
+  /* Work out the correct shift.  */
+  sv_f32_t shift = svsel_f32 (pred_xlt0, sv_f32 (-2.0), sv_f32 (0.0));
+  shift = svsel_f32 (pred_aygtax, svadd_n_f32_x (pg, shift, 1.0), shift);
+  shift = svmul_f32_x (pg, shift, PiOver2);
+
+  sv_f32_t ret = __sv_atanf_common (pg, pg, z, z, shift);
+
+  /* Account for the sign of x and y.  */
+  ret = sv_as_f32_u32 (sveor_u32_x (pg, sv_as_u32_f32 (ret), sign_xy));
+
+  if (unlikely (svptest_any (pg, cmp_xy)))
+    {
+      return specialcase (y, x, ret, cmp_xy);
+    }
+
+  return ret;
+}
+
+PL_ALIAS (__sv_atan2f_x, _ZGVsMxvv_atan2f)
+
+/* Arity of 2 means no mathbench entry emitted. See test/mathbench_funcs.h.  */
+PL_SIG (SV, F, 2, atan2)
+PL_TEST_ULP (__sv_atan2f, 2.45)
+PL_TEST_INTERVAL (__sv_atan2f, -10.0, 10.0, 50000)
+PL_TEST_INTERVAL (__sv_atan2f, -1.0, 1.0, 40000)
+PL_TEST_INTERVAL (__sv_atan2f, 0.0, 1.0, 40000)
+PL_TEST_INTERVAL (__sv_atan2f, 1.0, 100.0, 40000)
+PL_TEST_INTERVAL (__sv_atan2f, 1e6, 1e32, 40000)
+#endif