2  * Single-precision vector log function.
4  * Copyright (c) 2019-2024, Arm Limited.
5  * SPDX-License-Identifier: MIT OR Apache-2.0 WITH LLVM-exception
19   .c0 = -0x1.3e737cp-3f,
20   .c1 = 0x1.5a9aa2p-3f,
21   .c2 = V4 (-0x1.4f9934p-3f),
22   .c3 = 0x1.961348p-3f,
23   .c4 = V4 (-0x1.00187cp-2f),
24   .c5 = 0x1.555d7cp-2f,
25   .c6 = V4 (-0x1.ffffc8p-2f),
26   .ln2 = V4 (0x1.62e43p-1f),
28      optimised register use subnormals are detected after offset has been
29      subtracted, so lower bound is 0x0080000 - offset (which wraps around).  */
30   .offset_lower_bound = V4 (0x00800000 - 0x3f2aaaab),
31   .special_bound = V8 (0x7f00), /* top16(asuint32(inf) - 0x00800000).  */
37 special_case (float32x4_t p, uint32x4_t u_off, float32x4_t y, float32x4_t r2,  in special_case()  argument
41   return v_call_f32 (logf, vreinterpretq_f32_u32 (vaddq_u32 (u_off, d->off)),  in special_case()
42 		     vfmaq_f32 (p, y, r2), vmovl_u16 (cmp));  in special_case()
48   float32x4_t c1350 = vld1q_f32 (&d->c1);  in V_NAME_F1()
50   /* To avoid having to mov x out of the way, keep u after offset has been  in V_NAME_F1()
51      applied, and recover x by adding the offset back in the special-case  in V_NAME_F1()
53   uint32x4_t u_off = vsubq_u32 (vreinterpretq_u32_f32 (x), d->off);  in V_NAME_F1()
58   uint16x4_t cmp = vcge_u16 (vsubhn_u32 (u_off, d->offset_lower_bound),  in V_NAME_F1()
59 			     vget_low_u16 (d->special_bound));  in V_NAME_F1()
61   uint32x4_t u = vaddq_u32 (vandq_u32 (u_off, d->mantissa_mask), d->off);  in V_NAME_F1()
64   /* y = log(1+r) + n*ln2.  */  in V_NAME_F1()
67   float32x4_t p = vfmaq_laneq_f32 (d->c2, r, c1350, 0);  in V_NAME_F1()
68   float32x4_t q = vfmaq_laneq_f32 (d->c4, r, c1350, 1);  in V_NAME_F1()
69   float32x4_t y = vfmaq_laneq_f32 (d->c6, r, c1350, 2);  in V_NAME_F1()  local
73   y = vfmaq_f32 (y, q, r2);  in V_NAME_F1()
74   p = vfmaq_f32 (r, d->ln2, n);  in V_NAME_F1()
77     return special_case (p, u_off, y, r2, cmp, d);  in V_NAME_F1()
78   return vfmaq_f32 (p, y, r2);  in V_NAME_F1()
87 TEST_INTERVAL (V_NAME_F1 (log), 0x1p-4, 0x1p4, 500000)