1/*
2 * Copyright © 2022 Imagination Technologies Ltd.
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a copy
5 * of this software and associated documentation files (the "Software"), to deal
6 * in the Software without restriction, including without limitation the rights
7 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
8 * copies of the Software, and to permit persons to whom the Software is
9 * furnished to do so, subject to the following conditions:
10 *
11 * The above copyright notice and this permission notice (including the next
12 * paragraph) shall be included in all copies or substantial portions of the
13 * Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
18 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
20 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
21 * SOFTWARE.
22 */
23
24#include <stddef.h>
25#include <stdint.h>
26#include <stdlib.h>
27
28#include "rogue_constreg.h"
29#include "util/macros.h"
30
31/**
32 * \file rogue_constreg.c
33 *
34 * \brief Contains functions to find and allocate constant register values.
35 */
36
37/**
38 * \brief Mapping of constant register values and their indices.
39 */
40struct rogue_constreg {
41   uint32_t value;
42   size_t index;
43};
44
45#define CONSTREG(VALUE, INDEX)            \
46   {                                      \
47      .value = (VALUE), .index = (INDEX), \
48   }
49
50/**
51 * \brief Constant register values (sorted for bsearch).
52 */
53static const struct rogue_constreg const_regs[] = {
54   CONSTREG(0x00000000U, 0U), /* 0   (INT32) / 0.0 (Float) */
55   CONSTREG(0x00000001U, 1U), /* 1   (INT32) */
56   CONSTREG(0x00000002U, 2U), /* 2   (INT32) */
57   CONSTREG(0x00000003U, 3U), /* 3   (INT32) */
58   CONSTREG(0x00000004U, 4U), /* 4   (INT32) */
59   CONSTREG(0x00000005U, 5U), /* 5   (INT32) */
60   CONSTREG(0x00000006U, 6U), /* 6   (INT32) */
61   CONSTREG(0x00000007U, 7U), /* 7   (INT32) */
62   CONSTREG(0x00000008U, 8U), /* 8   (INT32) */
63   CONSTREG(0x00000009U, 9U), /* 9   (INT32) */
64   CONSTREG(0x0000000aU, 10U), /* 10  (INT32) */
65   CONSTREG(0x0000000bU, 11U), /* 11  (INT32) */
66   CONSTREG(0x0000000cU, 12U), /* 12  (INT32) */
67   CONSTREG(0x0000000dU, 13U), /* 13  (INT32) */
68   CONSTREG(0x0000000eU, 14U), /* 14  (INT32) */
69   CONSTREG(0x0000000fU, 15U), /* 15  (INT32) */
70   CONSTREG(0x00000010U, 16U), /* 16  (INT32) */
71   CONSTREG(0x00000011U, 17U), /* 17  (INT32) */
72   CONSTREG(0x00000012U, 18U), /* 18  (INT32) */
73   CONSTREG(0x00000013U, 19U), /* 19  (INT32) */
74   CONSTREG(0x00000014U, 20U), /* 20  (INT32) */
75   CONSTREG(0x00000015U, 21U), /* 21  (INT32) */
76   CONSTREG(0x00000016U, 22U), /* 22  (INT32) */
77   CONSTREG(0x00000017U, 23U), /* 23  (INT32) */
78   CONSTREG(0x00000018U, 24U), /* 24  (INT32) */
79   CONSTREG(0x00000019U, 25U), /* 25  (INT32) */
80   CONSTREG(0x0000001aU, 26U), /* 26  (INT32) */
81   CONSTREG(0x0000001bU, 27U), /* 27  (INT32) */
82   CONSTREG(0x0000001cU, 28U), /* 28  (INT32) */
83   CONSTREG(0x0000001dU, 29U), /* 29  (INT32) */
84   CONSTREG(0x0000001eU, 30U), /* 30  (INT32) */
85   CONSTREG(0x0000001fU, 31U), /* 31  (INT32) */
86   CONSTREG(0x0000007fU, 147U), /* 127 (INT32) */
87
88   CONSTREG(0x37800000U, 134U), /* 1.0f/65536f */
89   CONSTREG(0x38000000U, 135U), /* 1.0f/32768f */
90   CONSTREG(0x38800000U, 88U), /* float(2^-14) */
91   CONSTREG(0x39000000U, 87U), /* float(2^-13) */
92   CONSTREG(0x39800000U, 86U), /* float(2^-12) */
93   CONSTREG(0x3a000000U, 85U), /* float(2^-11) */
94   CONSTREG(0x3a800000U, 84U), /* float(2^-10) */
95   CONSTREG(0x3b000000U, 83U), /* float(2^-9) */
96   CONSTREG(0x3b4d2e1cU, 136U), /* 0.0031308f */
97   CONSTREG(0x3b800000U, 82U), /* float(2^-8) */
98   CONSTREG(0x3c000000U, 81U), /* float(2^-7) */
99   CONSTREG(0x3c800000U, 80U), /* float(2^-6) */
100   CONSTREG(0x3d000000U, 79U), /* float(2^-5) */
101   CONSTREG(0x3d25aee6U, 156U), /* 0.04045f */
102   CONSTREG(0x3d6147aeU, 140U), /* 0.055f */
103   CONSTREG(0x3d800000U, 78U), /* float(2^-4) */
104   CONSTREG(0x3d9e8391U, 157U), /* 1.0f/12.92f */
105   CONSTREG(0x3e000000U, 77U), /* float(2^-3) */
106   CONSTREG(0x3e2aaaabU, 153U), /* 1/6 */
107   CONSTREG(0x3e800000U, 76U), /* float(2^-2) */
108   CONSTREG(0x3e9a209bU, 145U), /* Log_10(2) */
109   CONSTREG(0x3ea2f983U, 128U), /* Float 1/PI */
110   CONSTREG(0x3eaaaaabU, 152U), /* 1/3 */
111   CONSTREG(0x3ebc5ab2U, 90U), /* 1/e */
112   CONSTREG(0x3ed55555U, 138U), /* 1.0f/2.4f */
113   CONSTREG(0x3f000000U, 75U), /* float(2^-1) */
114   CONSTREG(0x3f22f983U, 129U), /* Float 2/PI */
115   CONSTREG(0x3f317218U, 146U), /* Log_e(2) */
116   CONSTREG(0x3f3504f3U, 92U), /* Float 1/SQRT(2) */
117   CONSTREG(0x3f490fdbU, 93U), /* Float PI/4 */
118   CONSTREG(0x3f72a76fU, 158U), /* 1.0f/1.055f */
119   CONSTREG(0x3f800000U, 64U), /* 1.0f */
120   CONSTREG(0x3f860a92U, 151U), /* Pi/3 */
121   CONSTREG(0x3f870a3dU, 139U), /* 1.055f */
122   CONSTREG(0x3fa2f983U, 130U), /* Float 4/PI */
123   CONSTREG(0x3fb504f3U, 91U), /* Float SQRT(2) */
124   CONSTREG(0x3fb8aa3bU, 155U), /* Log_2(e) */
125   CONSTREG(0x3fc90fdbU, 94U), /* Float PI/2 */
126   CONSTREG(0x40000000U, 65U), /* float(2^1) */
127   CONSTREG(0x4019999aU, 159U), /* 2.4f */
128   CONSTREG(0x402df854U, 89U), /* e */
129   CONSTREG(0x40490fdbU, 95U), /* Float PI */
130   CONSTREG(0x40549a78U, 154U), /* Log_2(10) */
131   CONSTREG(0x40800000U, 66U), /* float(2^2) */
132   CONSTREG(0x40c90fdbU, 131U), /* Float 2*PI */
133   CONSTREG(0x41000000U, 67U), /* float(2^3) */
134   CONSTREG(0x41490fdbU, 132U), /* Float 4*PI */
135   CONSTREG(0x414eb852U, 137U), /* 12.92f */
136   CONSTREG(0x41800000U, 68U), /* float(2^4) */
137   CONSTREG(0x41c90fdbU, 133U), /* Float 8*PI */
138   CONSTREG(0x42000000U, 69U), /* float(2^5) */
139   CONSTREG(0x42800000U, 70U), /* float(2^6) */
140   CONSTREG(0x43000000U, 71U), /* float(2^7) */
141   CONSTREG(0x43800000U, 72U), /* float(2^8) */
142   CONSTREG(0x44000000U, 73U), /* float(2^9) */
143   CONSTREG(0x44800000U, 74U), /* float(2^10) */
144   CONSTREG(0x4b000000U, 149U), /* 2^23 */
145   CONSTREG(0x4b800000U, 150U), /* 2^24 */
146   CONSTREG(0x7f7fffffU, 148U), /* FLT_MAX */
147   CONSTREG(0x7f800000U, 142U), /* Infinity */
148   CONSTREG(0x7fff7fffU, 144U), /* ARGB1555 mask */
149   CONSTREG(0x80000000U, 141U), /* -0.0f */
150   CONSTREG(0xffffffffU, 143U), /* -1 */
151};
152
153#undef CONSTREG
154
155/**
156 * \brief Comparison function for bsearch() to support struct rogue_constreg.
157 *
158 * \param[in] lhs The left hand side of the comparison.
159 * \param[in] rhs The right hand side of the comparison.
160 * \return 0 if (lhs == rhs), -1 if (lhs < rhs), 1 if (lhs > rhs).
161 */
162static int constreg_cmp(const void *lhs, const void *rhs)
163{
164   const struct rogue_constreg *l = lhs;
165   const struct rogue_constreg *r = rhs;
166
167   if (l->value < r->value)
168      return -1;
169   else if (l->value > r->value)
170      return 1;
171
172   return 0;
173}
174
175/**
176 * \brief Determines whether a given integer value exists in a constant
177 * register.
178 *
179 * \param[in] value The value required.
180 * \return The index of the constant register containing the value, or
181 * ROGUE_NO_CONST_REG if the value is not found.
182 */
183size_t rogue_constreg_lookup(uint32_t value)
184{
185   struct rogue_constreg constreg_target = {
186      .value = value,
187   };
188   const struct rogue_constreg *constreg;
189
190   constreg = bsearch(&constreg_target,
191                      const_regs,
192                      ARRAY_SIZE(const_regs),
193                      sizeof(struct rogue_constreg),
194                      constreg_cmp);
195   if (!constreg)
196      return ROGUE_NO_CONST_REG;
197
198   return constreg->index;
199}
200