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-rw-r--r--math/aarch64/sve/sv_sincosf_common.h81
1 files changed, 81 insertions, 0 deletions
diff --git a/math/aarch64/sve/sv_sincosf_common.h b/math/aarch64/sve/sv_sincosf_common.h
new file mode 100644
index 000000000000..bda89ed24680
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+++ b/math/aarch64/sve/sv_sincosf_common.h
@@ -0,0 +1,81 @@
+/*
+ * Core approximation for single-precision vector sincos
+ *
+ * Copyright (c) 2023-2024, Arm Limited.
+ * SPDX-License-Identifier: MIT OR Apache-2.0 WITH LLVM-exception
+ */
+
+#include "sv_math.h"
+
+const static struct sv_sincosf_data
+{
+ float poly_sin[3], poly_cos[3], pio2[3], inv_pio2, shift, range_val;
+} sv_sincosf_data = {
+ .poly_sin = { /* Generated using Remez, odd coeffs only, in [-pi/4, pi/4]. */
+ -0x1.555546p-3, 0x1.11076p-7, -0x1.994eb4p-13 },
+ .poly_cos = { /* Generated using Remez, even coeffs only, in [-pi/4, pi/4]. */
+ 0x1.55554ap-5, -0x1.6c0c1ap-10, 0x1.99e0eep-16 },
+ .pio2 = { 0x1.921fb6p+0f, -0x1.777a5cp-25f, -0x1.ee59dap-50f },
+ .inv_pio2 = 0x1.45f306p-1f,
+ .shift = 0x1.8p23,
+ .range_val = 0x1p20
+};
+
+static inline svbool_t
+check_ge_rangeval (svbool_t pg, svfloat32_t x, const struct sv_sincosf_data *d)
+{
+ svbool_t in_bounds = svaclt (pg, x, d->range_val);
+ return svnot_z (pg, in_bounds);
+}
+
+/* Single-precision vector function allowing calculation of both sin and cos in
+ one function call, using shared argument reduction and separate low-order
+ polynomials.
+ Worst-case error for sin is 1.67 ULP:
+ sv_sincosf_sin(0x1.c704c4p+19) got 0x1.fff698p-5 want 0x1.fff69cp-5
+ Worst-case error for cos is 1.81 ULP:
+ sv_sincosf_cos(0x1.e506fp+19) got -0x1.ffec6ep-6 want -0x1.ffec72p-6. */
+static inline svfloat32x2_t
+sv_sincosf_inline (svbool_t pg, svfloat32_t x, const struct sv_sincosf_data *d)
+{
+ /* n = rint ( x / (pi/2) ). */
+ svfloat32_t q = svmla_x (pg, sv_f32 (d->shift), x, d->inv_pio2);
+ q = svsub_x (pg, q, d->shift);
+ svint32_t n = svcvt_s32_x (pg, q);
+
+ /* Reduce x such that r is in [ -pi/4, pi/4 ]. */
+ svfloat32_t r = x;
+ r = svmls_x (pg, r, q, d->pio2[0]);
+ r = svmls_x (pg, r, q, d->pio2[1]);
+ r = svmls_x (pg, r, q, d->pio2[2]);
+
+ /* Approximate sin(r) ~= r + r^3 * poly_sin(r^2). */
+ svfloat32_t r2 = svmul_x (pg, r, r), r3 = svmul_x (pg, r, r2);
+ svfloat32_t s = svmla_x (pg, sv_f32 (d->poly_sin[1]), r2, d->poly_sin[2]);
+ s = svmad_x (pg, r2, s, d->poly_sin[0]);
+ s = svmla_x (pg, r, r3, s);
+
+ /* Approximate cos(r) ~= 1 - (r^2)/2 + r^4 * poly_cos(r^2). */
+ svfloat32_t r4 = svmul_x (pg, r2, r2);
+ svfloat32_t p = svmla_x (pg, sv_f32 (d->poly_cos[1]), r2, d->poly_cos[2]);
+ svfloat32_t c = svmad_x (pg, sv_f32 (d->poly_cos[0]), r2, -0.5);
+ c = svmla_x (pg, c, r4, p);
+ c = svmad_x (pg, r2, c, 1);
+
+ svuint32_t un = svreinterpret_u32 (n);
+ /* If odd quadrant, swap cos and sin. */
+ svbool_t swap = svcmpeq (pg, svlsl_x (pg, un, 31), 0);
+ svfloat32_t ss = svsel (swap, s, c);
+ svfloat32_t cc = svsel (swap, c, s);
+
+ /* Fix signs according to quadrant.
+ ss = asfloat(asuint(ss) ^ ((n & 2) << 30))
+ cc = asfloat(asuint(cc) & (((n + 1) & 2) << 30)). */
+ svuint32_t sin_sign = svlsl_x (pg, svand_x (pg, un, 2), 30);
+ svuint32_t cos_sign = svlsl_x (
+ pg, svand_x (pg, svreinterpret_u32 (svadd_x (pg, n, 1)), 2), 30);
+ ss = svreinterpret_f32 (sveor_x (pg, svreinterpret_u32 (ss), sin_sign));
+ cc = svreinterpret_f32 (sveor_x (pg, svreinterpret_u32 (cc), cos_sign));
+
+ return svcreate2 (ss, cc);
+}