1 files changed, 83 insertions, 0 deletions
diff --git a/contrib/arm-optimized-routines/math/aarch64/sve/sv_log_inline.h b/contrib/arm-optimized-routines/math/aarch64/sve/sv_log_inline.h
new file mode 100644
index 000000000000..a1b169a0b727
--- /dev/null
+++ b/contrib/arm-optimized-routines/math/aarch64/sve/sv_log_inline.h
@@ -0,0 +1,83 @@
+/*
+ * Double-precision vector log(x) function - inline version
+ *
+ * Copyright (c) 2024, Arm Limited.
+ * SPDX-License-Identifier: MIT OR Apache-2.0 WITH LLVM-exception
+ */
+
+#include "sv_math.h"
+#include "math_config.h"
+
+#ifndef SV_LOG_INLINE_POLY_ORDER
+#  error Cannot use inline log helper without specifying poly order (options are 4 or 5)
+#endif
+
+#if SV_LOG_INLINE_POLY_ORDER == 4
+#  define POLY                                                                \
+    {                                                                         \
+      -0x1.ffffffffcbad3p-2, 0x1.555555578ed68p-2, -0x1.0000d3a1e7055p-2,     \
+	  0x1.999392d02a63ep-3                                                \
+    }
+#elif SV_LOG_INLINE_POLY_ORDER == 5
+#  define POLY                                                                \
+    {                                                                         \
+      -0x1.ffffffffffff7p-2, 0x1.55555555170d4p-2, -0x1.0000000399c27p-2,     \
+	  0x1.999b2e90e94cap-3, -0x1.554e550bd501ep-3                         \
+    }
+#else
+#  error Can only choose order 4 or 5 for log poly
+#endif
+
+struct sv_log_inline_data
+{
+  double poly[SV_LOG_INLINE_POLY_ORDER];
+  double ln2;
+  uint64_t off, sign_exp_mask;
+};
+
+#define SV_LOG_CONSTANTS                                                      \
+  {                                                                           \
+    .poly = POLY, .ln2 = 0x1.62e42fefa39efp-1,                                \
+    .sign_exp_mask = 0xfff0000000000000, .off = 0x3fe6900900000000            \
+  }
+
+#define P(i) sv_f64 (d->poly[i])
+#define N (1 << V_LOG_TABLE_BITS)
+
+static inline svfloat64_t
+sv_log_inline (svbool_t pg, svfloat64_t x, const struct sv_log_inline_data *d)
+{
+  svuint64_t ix = svreinterpret_u64 (x);
+
+  /* x = 2^k z; where z is in range [Off,2*Off) and exact.
+     The range is split into N subintervals.
+     The ith subinterval contains z and c is near its center.  */
+  svuint64_t tmp = svsub_x (pg, ix, d->off);
+  /* Calculate table index = (tmp >> (52 - V_LOG_TABLE_BITS)) % N.
+     The actual value of i is double this due to table layout.  */
+  svuint64_t i
+      = svand_x (pg, svlsr_x (pg, tmp, (51 - V_LOG_TABLE_BITS)), (N - 1) << 1);
+  svint64_t k
+      = svasr_x (pg, svreinterpret_s64 (tmp), 52); /* Arithmetic shift.  */
+  svuint64_t iz = svsub_x (pg, ix, svand_x (pg, tmp, 0xfffULL << 52));
+  svfloat64_t z = svreinterpret_f64 (iz);
+
+  /* Lookup in 2 global lists (length N).  */
+  svfloat64_t invc = svld1_gather_index (pg, &__v_log_data.table[0].invc, i);
+  svfloat64_t logc = svld1_gather_index (pg, &__v_log_data.table[0].logc, i);
+
+  /* log(x) = log1p(z/c-1) + log(c) + k*Ln2.  */
+  svfloat64_t r = svmad_x (pg, invc, z, -1);
+  svfloat64_t kd = svcvt_f64_x (pg, k);
+  /* hi = r + log(c) + k*Ln2.  */
+  svfloat64_t hi = svmla_x (pg, svadd_x (pg, logc, r), kd, __v_log_data.ln2);
+  /* y = r2*(A0 + r*A1 + r2*(A2 + r*A3 + r2*A4)) + hi.  */
+  svfloat64_t r2 = svmul_x (pg, r, r);
+  svfloat64_t y = svmla_x (pg, P (2), r, P (3));
+  svfloat64_t p = svmla_x (pg, P (0), r, P (1));
+#if SV_LOG_INLINE_POLY_ORDER == 5
+  y = svmla_x (pg, P (4), r2);
+#endif
+  y = svmla_x (pg, p, r2, y);
+  return svmla_x (pg, hi, r2, y);
+}