1 files changed, 76 insertions, 0 deletions
diff --git a/math/aarch64/sve/sv_sincospi_common.h b/math/aarch64/sve/sv_sincospi_common.h
new file mode 100644
index 000000000000..672ebbc8e855
--- /dev/null
+++ b/math/aarch64/sve/sv_sincospi_common.h
@@ -0,0 +1,76 @@
+/*
+ * Core approximation for double-precision SVE sincospi
+ *
+ * Copyright (c) 2024, Arm Limited.
+ * SPDX-License-Identifier: MIT OR Apache-2.0 WITH LLVM-exception
+ */
+
+#include "sv_math.h"
+#include "sv_poly_f64.h"
+
+static const struct sv_sincospi_data
+{
+  double c0, c2, c4, c6, c8;
+  double c1, c3, c5, c7, c9;
+  double range_val;
+} sv_sincospi_data = {
+  /* Polynomial coefficients generated using Remez algorithm,
+     see sinpi.sollya for details.  */
+  .c0 = 0x1.921fb54442d184p1,
+  .c1 = -0x1.4abbce625be53p2,
+  .c2 = 0x1.466bc6775ab16p1,
+  .c3 = -0x1.32d2cce62dc33p-1,
+  .c4 = 0x1.507834891188ep-4,
+  .c5 = -0x1.e30750a28c88ep-8,
+  .c6 = 0x1.e8f48308acda4p-12,
+  .c7 = -0x1.6fc0032b3c29fp-16,
+  .c8 = 0x1.af86ae521260bp-21,
+  .c9 = -0x1.012a9870eeb7dp-25,
+  /* Exclusive upper bound for a signed integer.  */
+  .range_val = 0x1p63
+};
+
+/* Double-precision vector function allowing calculation of both sinpi and
+   cospi in one function call, using shared argument reduction and polynomials.
+    Worst-case error for sin is 3.09 ULP:
+    _ZGVsMxvl8l8_sincospi_sin(0x1.7a41deb4b21e1p+14) got 0x1.fd54d0b327cf1p-1
+						    want 0x1.fd54d0b327cf4p-1.
+   Worst-case error for cos is 3.16 ULP:
+    _ZGVsMxvl8l8_sincospi_cos(-0x1.11e3c7e284adep-5) got 0x1.fd2da484ff3ffp-1
+						    want 0x1.fd2da484ff402p-1.
+ */
+static inline svfloat64x2_t
+sv_sincospi_inline (svbool_t pg, svfloat64_t x,
+		    const struct sv_sincospi_data *d)
+{
+  const svbool_t pt = svptrue_b64 ();
+
+  /* r = x - rint(x).  */
+  /* pt hints unpredicated instruction.  */
+  svfloat64_t rx = svrinta_x (pg, x);
+  svfloat64_t sr = svsub_x (pt, x, rx);
+
+  /* cospi(x) = sinpi(0.5 - abs(x)) for values -1/2 .. 1/2.  */
+  svfloat64_t cr = svsubr_x (pg, svabs_x (pg, sr), 0.5);
+
+  /* Pairwise Horner approximation for y = sin(r * pi).  */
+  /* pt hints unpredicated instruction.  */
+  svfloat64_t sr2 = svmul_x (pt, sr, sr);
+  svfloat64_t cr2 = svmul_x (pt, cr, cr);
+  svfloat64_t sr4 = svmul_x (pt, sr2, sr2);
+  svfloat64_t cr4 = svmul_x (pt, cr2, cr2);
+
+  /* If rint(x) is odd, the sign of the result should be inverted for sinpi and
+    re-introduced for cospi. cmp filters rxs that saturate to max sint.  */
+  svbool_t cmp = svaclt (pg, x, d->range_val);
+  svuint64_t odd = svlsl_x (pt, svreinterpret_u64 (svcvt_s64_z (pg, rx)), 63);
+  sr = svreinterpret_f64 (sveor_x (pt, svreinterpret_u64 (sr), odd));
+  cr = svreinterpret_f64 (sveor_m (cmp, svreinterpret_u64 (cr), odd));
+
+  svfloat64_t sinpix = svmul_x (
+      pt, sv_lw_pw_horner_9_f64_x (pg, sr2, sr4, &(d->c0), &(d->c1)), sr);
+  svfloat64_t cospix = svmul_x (
+      pt, sv_lw_pw_horner_9_f64_x (pg, cr2, cr4, &(d->c0), &(d->c1)), cr);
+
+  return svcreate2 (sinpix, cospix);
+}