* FS#10411 - Fixed point math code is bloated by Jeffrey Goode
* Set svn:keywords properties git-svn-id: svn://svn.rockbox.org/rockbox/trunk@21701 a1c6a512-1295-4272-9138-f99709370657
This commit is contained in:
Maurus Cuelenaere
parent
616905f965
commit
8d4d4610b6
3 changed files with 43 additions and 92 deletions
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@ -5,7 +5,7 @@
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* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
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* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
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* \/ \/ \/ \/ \/
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* $Id: fixedpoint.h -1 $
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* $Id$
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*
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* Copyright (C) 2006 Jens Arnold
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*
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@ -5,7 +5,7 @@
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* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
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* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
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* \/ \/ \/ \/ \/
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* $Id: fixedpoint.c -1 $
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* $Id$
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*
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* Copyright (C) 2006 Jens Arnold
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*
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@ -261,24 +261,18 @@ long fp16_log(int x) {
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#if (!defined(PLUGIN) && !defined(CODEC))
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/** MODIFIED FROM replaygain.c */
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/* These math routines have 64-bit internal precision to avoid overflows.
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* Arguments and return values are 32-bit (long) precision.
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*/
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#define FP_MUL64(x, y) (((x) * (y)) >> (fracbits))
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#define FP_DIV64(x, y) (((x) << (fracbits)) / (y))
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static long long fp_exp10(long long x, unsigned int fracbits);
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/* static long long fp_log10(long long n, unsigned int fracbits); */
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#define FP_MUL_FRAC(x, y) fp_mul(x, y, fracbits)
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#define FP_DIV_FRAC(x, y) fp_div(x, y, fracbits)
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/* constants in fixed point format, 28 fractional bits */
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#define FP28_LN2 (186065279LL) /* ln(2) */
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#define FP28_LN2_INV (387270501LL) /* 1/ln(2) */
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#define FP28_EXP_ZERO (44739243LL) /* 1/6 */
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#define FP28_EXP_ONE (-745654LL) /* -1/360 */
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#define FP28_EXP_TWO (12428LL) /* 1/21600 */
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#define FP28_LN10 (618095479LL) /* ln(10) */
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#define FP28_LOG10OF2 (80807124LL) /* log10(2) */
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#define FP28_LN2 (186065279L) /* ln(2) */
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#define FP28_LN2_INV (387270501L) /* 1/ln(2) */
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#define FP28_EXP_ZERO (44739243L) /* 1/6 */
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#define FP28_EXP_ONE (-745654L) /* -1/360 */
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#define FP28_EXP_TWO (12428L) /* 1/21600 */
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#define FP28_LN10 (618095479L) /* ln(10) */
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#define FP28_LOG10OF2 (80807124L) /* log10(2) */
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#define TOL_BITS 2 /* log calculation tolerance */
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@ -290,24 +284,24 @@ static long long fp_exp10(long long x, unsigned int fracbits);
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/** FIXED POINT EXP10
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* Return 10^x as FP integer. Argument is FP integer.
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*/
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static long long fp_exp10(long long x, unsigned int fracbits)
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static long fp_exp10(long x, unsigned int fracbits)
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{
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long long k;
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long long z;
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long long R;
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long long xp;
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long k;
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long z;
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long R;
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long xp;
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/* scale constants */
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const long long fp_one = (1 << fracbits);
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const long long fp_half = (1 << (fracbits - 1));
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const long long fp_two = (2 << fracbits);
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const long long fp_mask = (fp_one - 1);
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const long long fp_ln2_inv = (FP28_LN2_INV >> (28 - fracbits));
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const long long fp_ln2 = (FP28_LN2 >> (28 - fracbits));
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const long long fp_ln10 = (FP28_LN10 >> (28 - fracbits));
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const long long fp_exp_zero = (FP28_EXP_ZERO >> (28 - fracbits));
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const long long fp_exp_one = (FP28_EXP_ONE >> (28 - fracbits));
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const long long fp_exp_two = (FP28_EXP_TWO >> (28 - fracbits));
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const long fp_one = (1 << fracbits);
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const long fp_half = (1 << (fracbits - 1));
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const long fp_two = (2 << fracbits);
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const long fp_mask = (fp_one - 1);
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const long fp_ln2_inv = (FP28_LN2_INV >> (28 - fracbits));
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const long fp_ln2 = (FP28_LN2 >> (28 - fracbits));
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const long fp_ln10 = (FP28_LN10 >> (28 - fracbits));
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const long fp_exp_zero = (FP28_EXP_ZERO >> (28 - fracbits));
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const long fp_exp_one = (FP28_EXP_ONE >> (28 - fracbits));
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const long fp_exp_two = (FP28_EXP_TWO >> (28 - fracbits));
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/* exp(0) = 1 */
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if (x == 0)
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@ -316,21 +310,21 @@ static long long fp_exp10(long long x, unsigned int fracbits)
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}
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/* convert from base 10 to base e */
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x = FP_MUL64(x, fp_ln10);
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x = FP_MUL_FRAC(x, fp_ln10);
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/* calculate exp(x) */
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k = (FP_MUL64(abs(x), fp_ln2_inv) + fp_half) & ~fp_mask;
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k = (FP_MUL_FRAC(abs(x), fp_ln2_inv) + fp_half) & ~fp_mask;
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if (x < 0)
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{
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k = -k;
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}
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x -= FP_MUL64(k, fp_ln2);
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z = FP_MUL64(x, x);
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R = fp_two + FP_MUL64(z, fp_exp_zero + FP_MUL64(z, fp_exp_one
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+ FP_MUL64(z, fp_exp_two)));
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xp = fp_one + FP_DIV64(FP_MUL64(fp_two, x), R - x);
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x -= FP_MUL_FRAC(k, fp_ln2);
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z = FP_MUL_FRAC(x, x);
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R = fp_two + FP_MUL_FRAC(z, fp_exp_zero + FP_MUL_FRAC(z, fp_exp_one
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+ FP_MUL_FRAC(z, fp_exp_two)));
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xp = fp_one + FP_DIV_FRAC(FP_MUL_FRAC(fp_two, x), R - x);
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if (k < 0)
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{
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@ -341,7 +335,7 @@ static long long fp_exp10(long long x, unsigned int fracbits)
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k = fp_one << (k >> fracbits);
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}
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return FP_MUL64(k, xp);
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return FP_MUL_FRAC(k, xp);
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}
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@ -349,13 +343,13 @@ static long long fp_exp10(long long x, unsigned int fracbits)
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/** FIXED POINT LOG10
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* Return log10(x) as FP integer. Argument is FP integer.
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*/
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static long long fp_log10(long long n, unsigned int fracbits)
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static long fp_log10(long n, unsigned int fracbits)
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{
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/* Calculate log2 of argument */
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long long log2, frac;
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const long long fp_one = (1 << fracbits);
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const long long fp_two = (2 << fracbits);
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long log2, frac;
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const long fp_one = (1 << fracbits);
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const long fp_two = (2 << fracbits);
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const long tolerance = (1 << ((fracbits / 2) + 2));
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if (n <=0) return FP_NEGINF;
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@ -378,7 +372,7 @@ static long long fp_log10(long long n, unsigned int fracbits)
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while (frac > tolerance)
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{
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frac >>= 1;
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n = FP_MUL64(n, n);
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n = FP_MUL_FRAC(n, n);
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if (n >= fp_two)
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{
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n >>= 1;
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@ -387,31 +381,15 @@ static long long fp_log10(long long n, unsigned int fracbits)
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}
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/* convert log2 to log10 */
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return FP_MUL64(log2, (FP28_LOG10OF2 >> (28 - fracbits)));
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return FP_MUL_FRAC(log2, (FP28_LOG10OF2 >> (28 - fracbits)));
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}
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/** CONVERT FACTOR TO DECIBELS */
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long fp_decibels(unsigned long factor, unsigned int fracbits)
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{
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long long decibels;
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long long f = (long long)factor;
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bool neg;
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/* keep factor in signed long range */
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if (f >= (1LL << 31))
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f = (1LL << 31) - 1;
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/* decibels = 20 * log10(factor) */
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decibels = FP_MUL64((20LL << fracbits), fp_log10(f, fracbits));
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/* keep result in signed long range */
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if ((neg = (decibels < 0)))
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decibels = -decibels;
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if (decibels >= (1LL << 31))
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return neg ? FP_NEGINF : FP_INF;
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return neg ? (long)-decibels : (long)decibels;
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return FP_MUL_FRAC((20L << fracbits), fp_log10(factor, fracbits));
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}
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#endif /* unused code */
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@ -419,34 +397,7 @@ long fp_decibels(unsigned long factor, unsigned int fracbits)
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/** CONVERT DECIBELS TO FACTOR */
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long fp_factor(long decibels, unsigned int fracbits)
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{
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bool neg;
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long long factor;
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long long db = (long long)decibels;
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/* if decibels is 0, factor is 1 */
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if (db == 0)
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return (1L << fracbits);
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/* calculate for positive decibels only */
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if ((neg = (db < 0)))
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db = -db;
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/* factor = 10 ^ (decibels / 20) */
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factor = fp_exp10(FP_DIV64(db, (20LL << fracbits)), fracbits);
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/* keep result in signed long range, return 0 if very small */
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if (factor >= (1LL << 31))
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{
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if (neg)
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return 0;
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else
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return FP_INF;
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}
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/* if negative argument, factor is 1 / result */
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if (neg)
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factor = FP_DIV64((1LL << fracbits), factor);
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return (long)factor;
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return fp_exp10(FP_DIV_FRAC(decibels, (20L << fracbits)), fracbits);
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}
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#endif /* !PLUGIN and !CODEC */
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@ -5,7 +5,7 @@
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* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
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* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
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* \/ \/ \/ \/ \/
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* $Id: fixedpoint.h -1 $
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* $Id$
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*
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* Copyright (C) 2006 Jens Arnold
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*
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