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Take 2 at 'Consolidate all fixed point math routines in one library' (FS#10400) by Jeffrey Goode

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git-svn-id: svn://svn.rockbox.org/rockbox/trunk@21664 a1c6a512-1295-4272-9138-f99709370657
This commit is contained in:
Maurus Cuelenaere 2009-07-05 18:06:07 +00:00
parent 427bf0b893
commit 802743a061
22 changed files with 754 additions and 755 deletions
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45
apps/plugins/lib/fixedpoint.h
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@ -21,11 +21,44 @@
*
****************************************************************************/
long fsincos(unsigned long phase, long *cos);
long fsqrt(long a, unsigned int fracbits);
long cos_int(int val);
long sin_int(int val);
long flog(int x);
/** PLUGINS - FIXED POINT MATH ROUTINES - USAGE
*
* - x and y arguments are fixed point integers
* - fracbits is the number of fractional bits in the argument(s)
* - functions return long fixed point integers with the specified number
* of fractional bits unless otherwise specified
*
* Calculate sin and cos of an angle:
* fp_sincos(phase, *cos)
* where phase is a 32 bit unsigned integer with 0 representing 0
* and 0xFFFFFFFF representing 2*pi, and *cos is the address to
* a long signed integer. Value returned is a long signed integer
* from LONG_MIN to LONG_MAX, representing -1 to 1 respectively.
* That is, value is a fixed point integer with 31 fractional bits.
*
* Take square root of a fixed point number:
* fp_sqrt(x, fracbits)
*
* Calculate sin or cos of an angle (very fast, from a table):
* fp14_sin(angle)
* fp14_cos(angle)
* where angle is a non-fixed point integer in degrees. Value
* returned is a fixed point integer with 14 fractional bits.
*
* Calculate the natural log of a positive fixed point integer
* fp16_log(x)
* where x and the value returned are fixed point integers
* with 16 fractional bits.
*/
#ifndef _FIXEDPOINT_H_PLUGINS
#define _FIXEDPOINT_H_PLUGINS
long fp_sincos(unsigned long phase, long *cos);
long fp_sqrt(long a, unsigned int fracbits);
long fp14_cos(int val);
long fp14_sin(int val);
long fp16_log(int x);
/* fast unsigned multiplication (16x16bit->32bit or 32x32bit->32bit,
* whichever is faster for the architecture) */
@ -34,3 +67,5 @@ long flog(int x);
#else /* SH1, coldfire */
#define FMULU(a, b) ((uint32_t) (((uint16_t) (a)) * ((uint16_t) (b))))
#endif
#endif