159 lines
3.5 KiB
C
159 lines
3.5 KiB
C
/*
|
|
* 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
|
|
|