1/*
  2 * Copyright 2015 Advanced Micro Devices, Inc.
  3 *
  4 * Permission is hereby granted, free of charge, to any person obtaining a
  5 * copy of this software and associated documentation files (the "Software"),
  6 * to deal in the Software without restriction, including without limitation
  7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  8 * and/or sell copies of the Software, and to permit persons to whom the
  9 * Software is furnished to do so, subject to the following conditions:
 10 *
 11 * The above copyright notice and this permission notice shall be included in
 12 * all copies or substantial portions of the Software.
 13 *
 14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 17 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
 18 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 19 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 20 * OTHER DEALINGS IN THE SOFTWARE.
 21 *
 22 * Authors: AMD
 23 *
 24 */
 25#include "dm_services.h"
 26#include "bw_fixed.h"
 27
 28
 29#define MIN_I64 \
 30	(int64_t)(-(1LL << 63))
 31
 32#define MAX_I64 \
 33	(int64_t)((1ULL << 63) - 1)
 34
 35#define FRACTIONAL_PART_MASK \
 36	((1ULL << BW_FIXED_BITS_PER_FRACTIONAL_PART) - 1)
 37
 38#define GET_FRACTIONAL_PART(x) \
 39	(FRACTIONAL_PART_MASK & (x))
 40
 41static uint64_t abs_i64(int64_t arg)
 42{
 43	if (arg >= 0)
 44		return (uint64_t)(arg);
 45	else
 46		return (uint64_t)(-arg);
 47}
 48
 49struct bw_fixed bw_int_to_fixed_nonconst(int64_t value)
 50{
 51	struct bw_fixed res;
 52	ASSERT(value < BW_FIXED_MAX_I32 && value > BW_FIXED_MIN_I32);
 53	res.value = value << BW_FIXED_BITS_PER_FRACTIONAL_PART;
 54	return res;
 55}
 56
 57struct bw_fixed bw_frc_to_fixed(int64_t numerator, int64_t denominator)
 58{
 59	struct bw_fixed res;
 60	bool arg1_negative = numerator < 0;
 61	bool arg2_negative = denominator < 0;
 62	uint64_t arg1_value;
 63	uint64_t arg2_value;
 64	uint64_t remainder;
 65
 66	/* determine integer part */
 67	uint64_t res_value;
 68
 69	ASSERT(denominator != 0);
 70
 71	arg1_value = abs_i64(numerator);
 72	arg2_value = abs_i64(denominator);
 73	res_value = div64_u64_rem(arg1_value, arg2_value, &remainder);
 74
 75	ASSERT(res_value <= BW_FIXED_MAX_I32);
 76
 77	/* determine fractional part */
 78	{
 79		uint32_t i = BW_FIXED_BITS_PER_FRACTIONAL_PART;
 80
 81		do
 82		{
 83			remainder <<= 1;
 84
 85			res_value <<= 1;
 86
 87			if (remainder >= arg2_value)
 88			{
 89				res_value |= 1;
 90				remainder -= arg2_value;
 91			}
 92		} while (--i != 0);
 93	}
 94
 95	/* round up LSB */
 96	{
 97		uint64_t summand = (remainder << 1) >= arg2_value;
 98
 99		ASSERT(res_value <= MAX_I64 - summand);
100
101		res_value += summand;
102	}
103
104	res.value = (int64_t)(res_value);
105
106	if (arg1_negative ^ arg2_negative)
107		res.value = -res.value;
108	return res;
109}
110
111struct bw_fixed bw_floor2(
112	const struct bw_fixed arg,
113	const struct bw_fixed significance)
114{
115	struct bw_fixed result;
116	int64_t multiplicand;
117
118	multiplicand = div64_s64(arg.value, abs_i64(significance.value));
119	result.value = abs_i64(significance.value) * multiplicand;
120	ASSERT(abs_i64(result.value) <= abs_i64(arg.value));
121	return result;
122}
123
124struct bw_fixed bw_ceil2(
125	const struct bw_fixed arg,
126	const struct bw_fixed significance)
127{
128	struct bw_fixed result;
129	int64_t multiplicand;
130
131	multiplicand = div64_s64(arg.value, abs_i64(significance.value));
132	result.value = abs_i64(significance.value) * multiplicand;
133	if (abs_i64(result.value) < abs_i64(arg.value)) {
134		if (arg.value < 0)
135			result.value -= abs_i64(significance.value);
136		else
137			result.value += abs_i64(significance.value);
138	}
139	return result;
140}
141
142struct bw_fixed bw_mul(const struct bw_fixed arg1, const struct bw_fixed arg2)
143{
144	struct bw_fixed res;
145
146	bool arg1_negative = arg1.value < 0;
147	bool arg2_negative = arg2.value < 0;
148
149	uint64_t arg1_value = abs_i64(arg1.value);
150	uint64_t arg2_value = abs_i64(arg2.value);
151
152	uint64_t arg1_int = BW_FIXED_GET_INTEGER_PART(arg1_value);
153	uint64_t arg2_int = BW_FIXED_GET_INTEGER_PART(arg2_value);
154
155	uint64_t arg1_fra = GET_FRACTIONAL_PART(arg1_value);
156	uint64_t arg2_fra = GET_FRACTIONAL_PART(arg2_value);
157
158	uint64_t tmp;
159
160	res.value = arg1_int * arg2_int;
161
162	ASSERT(res.value <= BW_FIXED_MAX_I32);
163
164	res.value <<= BW_FIXED_BITS_PER_FRACTIONAL_PART;
165
166	tmp = arg1_int * arg2_fra;
167
168	ASSERT(tmp <= (uint64_t)(MAX_I64 - res.value));
169
170	res.value += tmp;
171
172	tmp = arg2_int * arg1_fra;
173
174	ASSERT(tmp <= (uint64_t)(MAX_I64 - res.value));
175
176	res.value += tmp;
177
178	tmp = arg1_fra * arg2_fra;
179
180	tmp = (tmp >> BW_FIXED_BITS_PER_FRACTIONAL_PART) +
181		(tmp >= (uint64_t)(bw_frc_to_fixed(1, 2).value));
182
183	ASSERT(tmp <= (uint64_t)(MAX_I64 - res.value));
184
185	res.value += tmp;
186
187	if (arg1_negative ^ arg2_negative)
188		res.value = -res.value;
189	return res;
190}
191