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Consolidate identical fixedpoint exp and ln functions.

Browse source 
grey_core.c and fixedpoint.c each had their own copies. grey_core.c
can use the ones fixedpoint.c. fixedpoint.c gets the more complete and
optimized version of fp_16exp from grey_core.c.

Change-Id: I43ee3add60796b06ed12012fbbd91815d64675a6
This commit is contained in:
Michael Sevakis 2013-04-09 19:07:35 -04:00
parent 9a19a22d85
commit f5b7134f59
2 changed files with 36 additions and 89 deletions
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52
apps/plugins/lib/grey_core.c
View file

@ -27,6 +27,7 @@
#include "plugin.h"
#include "grey.h"
#include "fixedpoint.h"
#if defined(HAVE_ADJUSTABLE_CPU_FREQ) && \
(defined(CPU_PP) || (CONFIG_LCD == LCD_TL0350A))
@ -368,8 +369,6 @@ static const unsigned char lcdlinear[256] = {
/* Prototypes */
static inline void _deferred_update(void) __attribute__ ((always_inline));
static int exp_s16p16(int x);
static int log_s16p16(int x);
static void grey_screendump_hook(int fd);
static void fill_gvalues(void);
#ifdef SIMULATOR
@ -501,53 +500,6 @@ static void _timer_isr(void)
#endif /* !SIMULATOR */
/* fixed point exp() */
static int exp_s16p16(int x)
{
int t;
int y = 0x00010000;
if (x < 0) x += 0xb1721, y >>= 16;
t = x - 0x58b91; if (t >= 0) x = t, y <<= 8;
t = x - 0x2c5c8; if (t >= 0) x = t, y <<= 4;
t = x - 0x162e4; if (t >= 0) x = t, y <<= 2;
t = x - 0x0b172; if (t >= 0) x = t, y <<= 1;
t = x - 0x067cd; if (t >= 0) x = t, y += y >> 1;
t = x - 0x03920; if (t >= 0) x = t, y += y >> 2;
t = x - 0x01e27; if (t >= 0) x = t, y += y >> 3;
t = x - 0x00f85; if (t >= 0) x = t, y += y >> 4;
t = x - 0x007e1; if (t >= 0) x = t, y += y >> 5;
t = x - 0x003f8; if (t >= 0) x = t, y += y >> 6;
t = x - 0x001fe; if (t >= 0) x = t, y += y >> 7;
y += ((y >> 8) * x) >> 8;
return y;
}
/* fixed point log() */
static int log_s16p16(int x)
{
int t;
int y = 0xa65af;
if (x < 0x00008000) x <<=16, y -= 0xb1721;
if (x < 0x00800000) x <<= 8, y -= 0x58b91;
if (x < 0x08000000) x <<= 4, y -= 0x2c5c8;
if (x < 0x20000000) x <<= 2, y -= 0x162e4;
if (x < 0x40000000) x <<= 1, y -= 0x0b172;
t = x + (x >> 1); if ((t & 0x80000000) == 0) x = t, y -= 0x067cd;
t = x + (x >> 2); if ((t & 0x80000000) == 0) x = t, y -= 0x03920;
t = x + (x >> 3); if ((t & 0x80000000) == 0) x = t, y -= 0x01e27;
t = x + (x >> 4); if ((t & 0x80000000) == 0) x = t, y -= 0x00f85;
t = x + (x >> 5); if ((t & 0x80000000) == 0) x = t, y -= 0x007e1;
t = x + (x >> 6); if ((t & 0x80000000) == 0) x = t, y -= 0x003f8;
t = x + (x >> 7); if ((t & 0x80000000) == 0) x = t, y -= 0x001fe;
x = 0x80000000 - x;
y -= x >> 15;
return y;
}
static void fill_gvalues(void)
{
int i;
@ -560,7 +512,7 @@ static void fill_gvalues(void)
#endif
for (i = 0; i < 256; i++)
{
data = exp_s16p16((_GREY_GAMMA * log_s16p16(i * 257 + 1)) >> 8) + 128;
data = fp16_exp((_GREY_GAMMA * fp16_log(i * 257 + 1)) >> 8) + 128;
data = (data - (data >> 8)) >> 8; /* approx. data /= 257 */
data = ((lcdlinear[data ^ imask] ^ imask) << 7) + 127;
_grey_info.gvalue[i] = (data + (data >> 8)) >> 8;