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minor tweaks to frac_div32()

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This commit is contained in:
Jean-Marc Valin 2010-06-17 00:35:26 -04:00
parent bd82ca80f7
commit 3a9699ee94
1 changed files with 8 additions and 8 deletions
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16
libcelt/plc.c
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@ -6,13 +6,14 @@
#ifdef FIXED_POINT #ifdef FIXED_POINT
static celt_word32 frac_div32(celt_word32 a, celt_word32 b) static celt_word32 frac_div32(celt_word32 a, celt_word32 b)
{ {
celt_word32 rcp, result, rem; celt_word16 rcp;
while (b<(1<<30)) celt_word32 result, rem;
{ int shift = 30-celt_ilog2(b);
a = SHL32(a,1); a = SHL32(a,shift);
b = SHL32(b,1); b = SHL32(b,shift);
}
rcp = PSHR32(celt_rcp(ROUND16(b,16)),2); /* 16-bit reciprocal */
rcp = ROUND16(celt_rcp(ROUND16(b,16)),2);
result = SHL32(MULT16_32_Q15(rcp, a),1); result = SHL32(MULT16_32_Q15(rcp, a),1);
rem = a-MULT32_32_Q31(result, b); rem = a-MULT32_32_Q31(result, b);
result += SHL32(MULT16_32_Q15(rcp, rem),1); result += SHL32(MULT16_32_Q15(rcp, rem),1);
@ -48,7 +49,6 @@ int p
for (j = 0; j < i; j++) for (j = 0; j < i; j++)
rr += MULT32_32_Q31(lpc[j],ac[i - j]); rr += MULT32_32_Q31(lpc[j],ac[i - j]);
rr += SHR32(ac[i + 1],3); rr += SHR32(ac[i + 1],3);
//r = -RC_SCALING*1.*SHL32(rr,3)/(error+1e-15);
r = -frac_div32(SHL32(rr,3), error); r = -frac_div32(SHL32(rr,3), error);
/* Update LPC coefficients and total error */ /* Update LPC coefficients and total error */
lpc[i] = SHR32(r,3); lpc[i] = SHR32(r,3);