diff options
Diffstat (limited to 'drivers/media/dvb-frontends/drxk_hard.c')
| -rw-r--r-- | drivers/media/dvb-frontends/drxk_hard.c | 104 |
1 files changed, 8 insertions, 96 deletions
diff --git a/drivers/media/dvb-frontends/drxk_hard.c b/drivers/media/dvb-frontends/drxk_hard.c index ec24d71e153d..41b637534ed4 100644 --- a/drivers/media/dvb-frontends/drxk_hard.c +++ b/drivers/media/dvb-frontends/drxk_hard.c @@ -34,6 +34,7 @@ #include "dvb_frontend.h" #include "drxk.h" #include "drxk_hard.h" +#include "dvb_math.h" static int PowerDownDVBT(struct drxk_state *state, bool setPowerMode); static int PowerDownQAM(struct drxk_state *state); @@ -201,98 +202,9 @@ static inline u32 Frac28a(u32 a, u32 c) return Q1; } -static u32 Log10Times100(u32 x) +static inline u32 log10times100(u32 value) { - static const u8 scale = 15; - static const u8 indexWidth = 5; - u8 i = 0; - u32 y = 0; - u32 d = 0; - u32 k = 0; - u32 r = 0; - /* - log2lut[n] = (1<<scale) * 200 * log2(1.0 + ((1.0/(1<<INDEXWIDTH)) * n)) - 0 <= n < ((1<<INDEXWIDTH)+1) - */ - - static const u32 log2lut[] = { - 0, /* 0.000000 */ - 290941, /* 290941.300628 */ - 573196, /* 573196.476418 */ - 847269, /* 847269.179851 */ - 1113620, /* 1113620.489452 */ - 1372674, /* 1372673.576986 */ - 1624818, /* 1624817.752104 */ - 1870412, /* 1870411.981536 */ - 2109788, /* 2109787.962654 */ - 2343253, /* 2343252.817465 */ - 2571091, /* 2571091.461923 */ - 2793569, /* 2793568.696416 */ - 3010931, /* 3010931.055901 */ - 3223408, /* 3223408.452106 */ - 3431216, /* 3431215.635215 */ - 3634553, /* 3634553.498355 */ - 3833610, /* 3833610.244726 */ - 4028562, /* 4028562.434393 */ - 4219576, /* 4219575.925308 */ - 4406807, /* 4406806.721144 */ - 4590402, /* 4590401.736809 */ - 4770499, /* 4770499.491025 */ - 4947231, /* 4947230.734179 */ - 5120719, /* 5120719.018555 */ - 5291081, /* 5291081.217197 */ - 5458428, /* 5458427.996830 */ - 5622864, /* 5622864.249668 */ - 5784489, /* 5784489.488298 */ - 5943398, /* 5943398.207380 */ - 6099680, /* 6099680.215452 */ - 6253421, /* 6253420.939751 */ - 6404702, /* 6404701.706649 */ - 6553600, /* 6553600.000000 */ - }; - - - if (x == 0) - return 0; - - /* Scale x (normalize) */ - /* computing y in log(x/y) = log(x) - log(y) */ - if ((x & ((0xffffffff) << (scale + 1))) == 0) { - for (k = scale; k > 0; k--) { - if (x & (((u32) 1) << scale)) - break; - x <<= 1; - } - } else { - for (k = scale; k < 31; k++) { - if ((x & (((u32) (-1)) << (scale + 1))) == 0) - break; - x >>= 1; - } - } - /* - Now x has binary point between bit[scale] and bit[scale-1] - and 1.0 <= x < 2.0 */ - - /* correction for divison: log(x) = log(x/y)+log(y) */ - y = k * ((((u32) 1) << scale) * 200); - - /* remove integer part */ - x &= ((((u32) 1) << scale) - 1); - /* get index */ - i = (u8) (x >> (scale - indexWidth)); - /* compute delta (x - a) */ - d = x & ((((u32) 1) << (scale - indexWidth)) - 1); - /* compute log, multiplication (d* (..)) must be within range ! */ - y += log2lut[i] + - ((d * (log2lut[i + 1] - log2lut[i])) >> (scale - indexWidth)); - /* Conver to log10() */ - y /= 108853; /* (log2(10) << scale) */ - r = (y >> 1); - /* rounding */ - if (y & ((u32) 1)) - r++; - return r; + return (100L * intlog10(value)) >> 24; } /****************************************************************************/ @@ -2530,8 +2442,8 @@ static int GetQAMSignalToNoise(struct drxk_state *state, } if (qamSlErrPower > 0) { - qamSlMer = Log10Times100(qamSlSigPower) - - Log10Times100((u32) qamSlErrPower); + qamSlMer = log10times100(qamSlSigPower) - + log10times100((u32) qamSlErrPower); } *pSignalToNoise = qamSlMer; @@ -2620,12 +2532,12 @@ static int GetDVBTSignalToNoise(struct drxk_state *state, */ /* log(x) x = 9bits * 9bits->18 bits */ - a = Log10Times100(EqRegTdTpsPwrOfs * + a = log10times100(EqRegTdTpsPwrOfs * EqRegTdTpsPwrOfs); /* log(x) x = 16bits * 7bits->23 bits */ - b = Log10Times100(EqRegTdReqSmbCnt * tpsCnt); + b = log10times100(EqRegTdReqSmbCnt * tpsCnt); /* log(x) x = (16bits + 16bits) << 15 ->32 bits */ - c = Log10Times100(SqrErrIQ); + c = log10times100(SqrErrIQ); iMER = a + b - c; } |