1/*
  2 * Copyright 2017 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
 26#include "dcn_calc_math.h"
 27
 28#define isNaN(number) ((number) != (number))
 29
 30/*
 31 * NOTE:
 32 *   This file is gcc-parseable HW gospel, coming straight from HW engineers.
 33 *
 34 * It doesn't adhere to Linux kernel style and sometimes will do things in odd
 35 * ways. Unless there is something clearly wrong with it the code should
 36 * remain as-is as it provides us with a guarantee from HW that it is correct.
 37 */
 38
 39float dcn_bw_mod(const float arg1, const float arg2)
 40{
 41	if (isNaN(arg1))
 42		return arg2;
 43	if (isNaN(arg2))
 44		return arg1;
 45	return arg1 - arg1 * ((int) (arg1 / arg2));
 46}
 47
 48float dcn_bw_min2(const float arg1, const float arg2)
 49{
 50	if (isNaN(arg1))
 51		return arg2;
 52	if (isNaN(arg2))
 53		return arg1;
 54	return arg1 < arg2 ? arg1 : arg2;
 55}
 56
 57unsigned int dcn_bw_max(const unsigned int arg1, const unsigned int arg2)
 58{
 59	return arg1 > arg2 ? arg1 : arg2;
 60}
 61float dcn_bw_max2(const float arg1, const float arg2)
 62{
 63	if (isNaN(arg1))
 64		return arg2;
 65	if (isNaN(arg2))
 66		return arg1;
 67	return arg1 > arg2 ? arg1 : arg2;
 68}
 69
 70float dcn_bw_floor2(const float arg, const float significance)
 71{
 72	if (significance == 0)
 73		return 0;
 74	return ((int) (arg / significance)) * significance;
 75}
 76
 77float dcn_bw_ceil2(const float arg, const float significance)
 78{
 79	float flr = dcn_bw_floor2(arg, significance);
 80	if (significance == 0)
 81		return 0;
 82	return flr + 0.00001 >= arg ? arg : flr + significance;
 83}
 84
 85float dcn_bw_max3(float v1, float v2, float v3)
 86{
 87	return v3 > dcn_bw_max2(v1, v2) ? v3 : dcn_bw_max2(v1, v2);
 88}
 89
 90float dcn_bw_max5(float v1, float v2, float v3, float v4, float v5)
 91{
 92	return dcn_bw_max3(v1, v2, v3) > dcn_bw_max2(v4, v5) ? dcn_bw_max3(v1, v2, v3) : dcn_bw_max2(v4, v5);
 93}
 94
 95float dcn_bw_pow(float a, float exp)
 96{
 97	float temp;
 98	/*ASSERT(exp == (int)exp);*/
 99	if ((int)exp == 0)
100		return 1;
101	temp = dcn_bw_pow(a, (int)(exp / 2));
102	if (((int)exp % 2) == 0) {
103		return temp * temp;
104	} else {
105		if ((int)exp > 0)
106			return a * temp * temp;
107		else
108			return (temp * temp) / a;
109	}
110}
111
112float dcn_bw_log(float a, float b)
113{
114	int * const exp_ptr = (int *)(&a);
115	int x = *exp_ptr;
116	const int log_2 = ((x >> 23) & 255) - 128;
117	x &= ~(255 << 23);
118	x += 127 << 23;
119	*exp_ptr = x;
120
121	a = ((-1.0f / 3) * a + 2) * a - 2.0f / 3;
122
123	if (b > 2.00001 || b < 1.99999)
124		return (a + log_2) / dcn_bw_log(b, 2);
125	else
126		return (a + log_2);
127}