ref: 19ae9fc9446067cb119b66a77c13a90e396f5ef1
parent: 3ec78b173be10c7681cba3c437fa00878cbdcbf4
author: Jean-Marc Valin <[email protected]>
date: Thu Mar 13 07:18:15 EDT 2008
fixed-point: simplifying the arithmetic in alg_quant()
--- a/libcelt/fixed_generic.h
+++ b/libcelt/fixed_generic.h
@@ -41,6 +41,8 @@
#define MULT32_32_Q31(a,b) ADD32(ADD32(SHL(MULT16_16(SHR((a),16),SHR((b),16)),1), SHR(MULT16_16SU(SHR((a),16),((b)&0x0000ffff)),15)), SHR(MULT16_16SU(SHR((b),16),((a)&0x0000ffff)),15))
+#define MULT32_32_Q32(a,b) ADD32(ADD32(MULT16_16(SHR((a),16),SHR((b),16)), SHR(MULT16_16SU(SHR((a),16),((b)&0x0000ffff)),16)), SHR(MULT16_16SU(SHR((b),16),((a)&0x0000ffff)),16))
+
#define QCONST16(x,bits) ((celt_word16_t)(.5+(x)*(((celt_word32_t)1)<<(bits))))
#define QCONST32(x,bits) ((celt_word32_t)(.5+(x)*(((celt_word32_t)1)<<(bits))))
--- a/libcelt/mathops.h
+++ b/libcelt/mathops.h
@@ -164,7 +164,7 @@
return VSHR32(EXTEND32(frac), -integer-2);
}
-static inline celt_word32_t celt_rcp(celt_word16_t x)
+static inline celt_word32_t celt_rcp(celt_word32_t x)
{int i, neg=0;
celt_word16_t n, frac;
@@ -174,8 +174,6 @@
neg = 1;
x = NEG16(x);
}
- if (x==0)
- return 0;
i = celt_ilog2(x);
n = VSHR32(x,i-16)-SHL32(EXTEND32(3),15);
frac = ADD16(C[0], MULT16_16_Q15(n, ADD16(C[1], MULT16_16_Q15(n, ADD16(C[2],
@@ -182,7 +180,7 @@
MULT16_16_Q15(n, ADD16(C[3], MULT16_16_Q15(n, (C[4])))))))));
if (neg)
frac = -frac;
- return SHL32(EXTEND32(frac),16-i);
+ return VSHR32(EXTEND32(frac),i-16);
}
#endif /* FIXED_POINT */
--- a/libcelt/vq.c
+++ b/libcelt/vq.c
@@ -218,24 +218,24 @@
if (iy[m][j]*sign < 0)
continue;
- spj = MULT16_16_P14(s, P[j]);
- aspj = MULT16_16_P15(alpha, spj);
+ spj = MULT16_16_Q14(s, P[j]);
+ aspj = MULT16_16_Q15(alpha, spj);
/* Updating the sums of the new pulse(s) */
- Rxy = xy[m] + MULT16_16(s,X[j]) - MULT16_16(MULT16_16_P15(alpha,spj),Rxp);
+ Rxy = xy[m] + MULT16_16(s,X[j]) - MULT16_16(MULT16_16_Q15(alpha,spj),Rxp);
Ryy = yy[m] + 2*MULT16_16(s,y[m][j]) + MULT16_16(s,s) +MULT16_16(aspj,MULT16_16_Q14(aspj,Rpp)) - 2*MULT16_32_Q14(aspj,yp[m]) - 2*MULT16_16(s,MULT16_16_Q14(aspj,P[j]));
Ryp = yp[m] + MULT16_16(spj, SUB16(QCONST16(1.f,14),MULT16_16_Q15(alpha,Rpp)));
/* Compute the gain such that ||p + g*y|| = 1 */
- g = MULT32_32_Q31(
- SHL32(celt_sqrt(MULT16_16(ROUND(Ryp,14),ROUND(Ryp,14)) + Ryy -
- MULT16_16(ROUND(Ryy,14),Rpp))
- - ROUND(Ryp,14), 14),
- celt_rcp(ROUND(Ryy,14)));
+ g = MULT16_32_Q15(
+ celt_sqrt(MULT16_16(ROUND(Ryp,14),ROUND(Ryp,14)) + Ryy -
+ MULT16_16(ROUND(Ryy,14),Rpp))
+ - ROUND(Ryp,14),
+ celt_rcp(SHR32(Ryy,12)));
/* Knowing that gain, what's the error: (x-g*y)^2
(result is negated and we discard x^2 because it's constant) */
/*score = 2.f*g*Rxy - 1.f*g*g*Ryy*NORM_SCALING_1;*/
- score = 2*MULT16_32_Q14(ROUND(Rxy,14),g) -
- MULT16_32_Q14(EXTRACT16(MULT16_32_Q14(ROUND(Ryy,14),g)),g);
+ score = 2*MULT16_32_Q14(ROUND(Rxy,14),g)
+ - MULT16_32_Q14(EXTRACT16(MULT16_32_Q14(ROUND(Ryy,14),g)),g);
if (score>nbest[Lupdate-1]->score)
{