freebsd-dev/sys/dev/syscons/plasma/fp16.h
Dag-Erling Smørgrav 23e6278ed9 Replace the cosine table with a sine table, which (due to the vagaries of
rounding) has better spread.  Implement fp16_sin() to go along with
fp16_cos().  In the rendering loop, switch from addition to subtraction
so the center of the pattern will be a trough rather than a peak.  This
is completely arbitrary, of course, but looks better to me.
2016-01-02 16:40:37 +00:00

86 lines
2.2 KiB
C

/*-
* Copyright (c) 2015 Dag-Erling Smørgrav
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#ifndef FP16_H_INCLUDED
#define FP16_H_INCLUDED
typedef signed long long fp16_t;
#define ItoFP16(n) ((signed long long)(n) << 16)
#define FP16toI(n) ((signed long long)(n) >> 16)
#ifndef _KERNEL
#define FP16toF(n) ((n) / 65536.0)
#endif
/* add a and b */
static inline fp16_t
fp16_add(fp16_t a, fp16_t b)
{
return (a + b);
}
/* subtract b from a */
static inline fp16_t
fp16_sub(fp16_t a, fp16_t b)
{
return (a - b);
}
/* multiply a by b */
static inline fp16_t
fp16_mul(fp16_t a, fp16_t b)
{
return (a * b >> 16);
}
/* divide a by b */
static inline fp16_t
fp16_div(fp16_t a, fp16_t b)
{
return ((a << 16) / b);
}
/* square root */
fp16_t fp16_sqrt(fp16_t);
#define FP16_2PI 411774
#define FP16_PI 205887
#define FP16_PI_2 102943
#define FP16_PI_4 51471
/* sine and cosine */
fp16_t fp16_sin(fp16_t);
fp16_t fp16_cos(fp16_t);
#endif