mirror of https://gitee.com/openkylin/linux.git
[media] drxk_hard: don't re-implement log10
X-Patchwork-Delegate: mchehab@redhat.com Log10 routine is already defined at dvb_math.h and provides a good enough approximation for 100 x log10(). So, instead of reinventing the wheel, use the already existing function. While here, don't use CamelCase on the function name. Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This commit is contained in:
Mauro Carvalho Chehab
parent
7df272563a
commit
b5e9eb6f52
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@ -34,6 +34,7 @@
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#include "dvb_frontend.h"
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#include "drxk.h"
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#include "drxk_hard.h"
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#include "dvb_math.h"
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static int PowerDownDVBT(struct drxk_state *state, bool setPowerMode);
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static int PowerDownQAM(struct drxk_state *state);
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@ -201,98 +202,9 @@ static inline u32 Frac28a(u32 a, u32 c)
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return Q1;
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}
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static u32 Log10Times100(u32 x)
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static inline u32 log10times100(u32 value)
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{
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static const u8 scale = 15;
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static const u8 indexWidth = 5;
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u8 i = 0;
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u32 y = 0;
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u32 d = 0;
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u32 k = 0;
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u32 r = 0;
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/*
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log2lut[n] = (1<<scale) * 200 * log2(1.0 + ((1.0/(1<<INDEXWIDTH)) * n))
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0 <= n < ((1<<INDEXWIDTH)+1)
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*/
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static const u32 log2lut[] = {
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0, /* 0.000000 */
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290941, /* 290941.300628 */
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573196, /* 573196.476418 */
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847269, /* 847269.179851 */
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1113620, /* 1113620.489452 */
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1372674, /* 1372673.576986 */
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1624818, /* 1624817.752104 */
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1870412, /* 1870411.981536 */
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2109788, /* 2109787.962654 */
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2343253, /* 2343252.817465 */
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2571091, /* 2571091.461923 */
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2793569, /* 2793568.696416 */
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3010931, /* 3010931.055901 */
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3223408, /* 3223408.452106 */
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3431216, /* 3431215.635215 */
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3634553, /* 3634553.498355 */
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3833610, /* 3833610.244726 */
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4028562, /* 4028562.434393 */
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4219576, /* 4219575.925308 */
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4406807, /* 4406806.721144 */
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4590402, /* 4590401.736809 */
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4770499, /* 4770499.491025 */
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4947231, /* 4947230.734179 */
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5120719, /* 5120719.018555 */
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5291081, /* 5291081.217197 */
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5458428, /* 5458427.996830 */
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5622864, /* 5622864.249668 */
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5784489, /* 5784489.488298 */
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5943398, /* 5943398.207380 */
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6099680, /* 6099680.215452 */
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6253421, /* 6253420.939751 */
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6404702, /* 6404701.706649 */
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6553600, /* 6553600.000000 */
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};
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if (x == 0)
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return 0;
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/* Scale x (normalize) */
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/* computing y in log(x/y) = log(x) - log(y) */
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if ((x & ((0xffffffff) << (scale + 1))) == 0) {
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for (k = scale; k > 0; k--) {
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if (x & (((u32) 1) << scale))
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break;
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x <<= 1;
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}
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} else {
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for (k = scale; k < 31; k++) {
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if ((x & (((u32) (-1)) << (scale + 1))) == 0)
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break;
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x >>= 1;
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}
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}
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/*
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Now x has binary point between bit[scale] and bit[scale-1]
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and 1.0 <= x < 2.0 */
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/* correction for divison: log(x) = log(x/y)+log(y) */
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y = k * ((((u32) 1) << scale) * 200);
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/* remove integer part */
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x &= ((((u32) 1) << scale) - 1);
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/* get index */
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i = (u8) (x >> (scale - indexWidth));
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/* compute delta (x - a) */
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d = x & ((((u32) 1) << (scale - indexWidth)) - 1);
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/* compute log, multiplication (d* (..)) must be within range ! */
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y += log2lut[i] +
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((d * (log2lut[i + 1] - log2lut[i])) >> (scale - indexWidth));
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/* Conver to log10() */
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y /= 108853; /* (log2(10) << scale) */
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r = (y >> 1);
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/* rounding */
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if (y & ((u32) 1))
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r++;
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return r;
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return (100L * intlog10(value)) >> 24;
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}
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/****************************************************************************/
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@ -2530,8 +2442,8 @@ static int GetQAMSignalToNoise(struct drxk_state *state,
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}
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if (qamSlErrPower > 0) {
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qamSlMer = Log10Times100(qamSlSigPower) -
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Log10Times100((u32) qamSlErrPower);
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qamSlMer = log10times100(qamSlSigPower) -
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log10times100((u32) qamSlErrPower);
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}
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*pSignalToNoise = qamSlMer;
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@ -2620,12 +2532,12 @@ static int GetDVBTSignalToNoise(struct drxk_state *state,
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*/
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/* log(x) x = 9bits * 9bits->18 bits */
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a = Log10Times100(EqRegTdTpsPwrOfs *
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a = log10times100(EqRegTdTpsPwrOfs *
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EqRegTdTpsPwrOfs);
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/* log(x) x = 16bits * 7bits->23 bits */
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b = Log10Times100(EqRegTdReqSmbCnt * tpsCnt);
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b = log10times100(EqRegTdReqSmbCnt * tpsCnt);
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/* log(x) x = (16bits + 16bits) << 15 ->32 bits */
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c = Log10Times100(SqrErrIQ);
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c = log10times100(SqrErrIQ);
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iMER = a + b - c;
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}
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