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/*
* This file is part of LibCSS.
* Licensed under the MIT License,
* http://www.opensource.org/licenses/mit-license.php
* Copyright 2008 John-Mark Bell <jmb@netsurf-browser.org>
*/
#ifndef libcss_fpmath_h_
#define libcss_fpmath_h_
#ifdef __cplusplus
extern "C"
{
#endif
#include <stdint.h>
#include <limits.h>
/* 22:10 fixed point math */
#define CSS_RADIX_POINT 10
/* type for fixed point numbers */
typedef int32_t css_fixed;
static inline css_fixed
css_add_fixed(const css_fixed x, const css_fixed y) {
int32_t ux = x;
int32_t uy = y;
int32_t res = ux + uy;
/* Calculate overflowed result. (Don't change the sign bit of ux) */
ux = (ux >> 31) + INT_MAX;
/* Force compiler to use cmovns instruction */
if ((int32_t) ((ux ^ uy) | ~(uy ^ res)) >= 0) {
res = ux;
}
return res;
}
static inline css_fixed
css_subtract_fixed(const css_fixed x, const css_fixed y) {
int32_t ux = x;
int32_t uy = y;
int32_t res = ux - uy;
ux = (ux >> 31) + INT_MAX;
/* Force compiler to use cmovns instruction */
if ((int32_t)((ux ^ uy) & (ux ^ res)) < 0) {
res = ux;
}
return res;
}
static inline css_fixed
css_divide_fixed(const css_fixed x, const css_fixed y) {
int64_t xx = ((int64_t)x << CSS_RADIX_POINT) / y;
if (xx < INT_MIN)
xx = INT_MIN;
if (xx > INT_MAX)
xx = INT_MAX;
return xx;
}
static inline css_fixed
css_multiply_fixed(const css_fixed x, const css_fixed y) {
int64_t xx = ((int64_t)x * (int64_t)y) >> CSS_RADIX_POINT;
if (xx < INT_MIN)
xx = INT_MIN;
if (xx > INT_MAX)
xx = INT_MAX;
return xx;
}
static inline css_fixed
css_int_to_fixed(const int a) {
int64_t xx = ((int64_t) a) << CSS_RADIX_POINT;
if (xx < INT_MIN)
xx = INT_MIN;
if (xx > INT_MAX)
xx = INT_MAX;
return xx;
}
static inline css_fixed
css_float_to_fixed(const float a) {
float xx = a * (float) (1 << CSS_RADIX_POINT);
if (xx < INT_MIN)
xx = INT_MIN;
if (xx > INT_MAX)
xx = INT_MAX;
return (css_fixed) xx;
}
/* Add two fixed point values */
#define FADD(a, b) (css_add_fixed((a), (b)))
/* Subtract two fixed point values */
#define FSUB(a, b) (css_subtract_fixed((a), (b)))
/* Multiply two fixed point values */
#define FMUL(a, b) (css_multiply_fixed((a), (b)))
/* Divide two fixed point values */
#define FDIV(a, b) (css_divide_fixed((a), (b)))
/* Convert a floating point value to fixed point */
#define FLTTOFIX(a) ((css_fixed) ((a) * (float) (1 << CSS_RADIX_POINT)))
/* Convert a fixed point value to floating point */
#define FIXTOFLT(a) ((float) (a) / (float) (1 << CSS_RADIX_POINT))
/* Convert an integer to a fixed point value */
#define INTTOFIX(a) (css_int_to_fixed(a))
/* Convert a fixed point value to an integer */
#define FIXTOINT(a) ((a) >> CSS_RADIX_POINT)
/* truncate a fixed point value */
#define TRUNCATEFIX(a) (a & ~((1 << CSS_RADIX_POINT)- 1 ))
/* Useful values */
#define F_PI_2 0x00000648 /* 1.5708 (PI/2) */
#define F_PI 0x00000c91 /* 3.1415 (PI) */
#define F_3PI_2 0x000012d9 /* 4.7124 (3PI/2) */
#define F_2PI 0x00001922 /* 6.2831 (2 PI) */
#define F_90 0x00016800 /* 90 */
#define F_180 0x0002d000 /* 180 */
#define F_270 0x00043800 /* 270 */
#define F_360 0x0005a000 /* 360 */
#define F_0_5 0x00000200 /* 0.5 */
#define F_1 0x00000400 /* 1 */
#define F_10 0x00002800 /* 10 */
#define F_72 0x00012000 /* 72 */
#define F_100 0x00019000 /* 100 */
#define F_200 0x00032000 /* 200 */
#define F_255 0x0003FC00 /* 255 */
#define F_300 0x0004b000 /* 300 */
#define F_400 0x00064000 /* 400 */
#ifdef __cplusplus
}
#endif
#endif
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