ref: 273906404c1647ef9f43c27fc1efced3c7af96f4
parent: ae3321849596094d204f9c3dbe485b5fde6e5782
author: Jean-Marc Valin <jmvalin@jmvalin.ca>
date: Thu Jul 21 15:40:23 EDT 2016
silencing overflows in MDCT and FFT
--- a/celt/_kiss_fft_guts.h
+++ b/celt/_kiss_fft_guts.h
@@ -58,12 +58,12 @@
# define S_MUL(a,b) MULT16_32_Q15(b, a)
# define C_MUL(m,a,b) \
- do{ (m).r = SUB32(S_MUL((a).r,(b).r) , S_MUL((a).i,(b).i)); \- (m).i = ADD32(S_MUL((a).r,(b).i) , S_MUL((a).i,(b).r)); }while(0)
+ do{ (m).r = SUB32_ovflw(S_MUL((a).r,(b).r) , S_MUL((a).i,(b).i)); \+ (m).i = ADD32_ovflw(S_MUL((a).r,(b).i) , S_MUL((a).i,(b).r)); }while(0)
# define C_MULC(m,a,b) \
- do{ (m).r = ADD32(S_MUL((a).r,(b).r) , S_MUL((a).i,(b).i)); \- (m).i = SUB32(S_MUL((a).i,(b).r) , S_MUL((a).r,(b).i)); }while(0)
+ do{ (m).r = ADD32_ovflw(S_MUL((a).r,(b).r) , S_MUL((a).i,(b).i)); \+ (m).i = SUB32_ovflw(S_MUL((a).i,(b).r) , S_MUL((a).r,(b).i)); }while(0)
# define C_MULBYSCALAR( c, s ) \
do{ (c).r = S_MUL( (c).r , s ) ;\@@ -77,17 +77,17 @@
DIVSCALAR( (c).i , div); }while (0)
#define C_ADD( res, a,b)\
- do {(res).r=ADD32((a).r,(b).r); (res).i=ADD32((a).i,(b).i); \+ do {(res).r=ADD32_ovflw((a).r,(b).r); (res).i=ADD32_ovflw((a).i,(b).i); \}while(0)
#define C_SUB( res, a,b)\
- do {(res).r=SUB32((a).r,(b).r); (res).i=SUB32((a).i,(b).i); \+ do {(res).r=SUB32_ovflw((a).r,(b).r); (res).i=SUB32_ovflw((a).i,(b).i); \}while(0)
#define C_ADDTO( res , a)\
- do {(res).r = ADD32((res).r, (a).r); (res).i = ADD32((res).i,(a).i);\+ do {(res).r = ADD32_ovflw((res).r, (a).r); (res).i = ADD32_ovflw((res).i,(a).i);\}while(0)
#define C_SUBFROM( res , a)\
- do {(res).r = ADD32((res).r,(a).r); (res).i = SUB32((res).i,(a).i); \+ do {(res).r = ADD32_ovflw((res).r,(a).r); (res).i = SUB32_ovflw((res).i,(a).i); \}while(0)
#if defined(OPUS_ARM_INLINE_ASM)
--- a/celt/arch.h
+++ b/celt/arch.h
@@ -186,6 +186,7 @@
#define NEG16(x) (-(x))
#define NEG32(x) (-(x))
+#define NEG32_ovflw(x) (-(x))
#define EXTRACT16(x) (x)
#define EXTEND32(x) (x)
#define SHR16(a,shift) (a)
@@ -209,6 +210,8 @@
#define SUB16(a,b) ((a)-(b))
#define ADD32(a,b) ((a)+(b))
#define SUB32(a,b) ((a)-(b))
+#define ADD32_ovflw(a,b) ((a)+(b))
+#define SUB32_ovflw(a,b) ((a)-(b))
#define MULT16_16_16(a,b) ((a)*(b))
#define MULT16_16(a,b) ((opus_val32)(a)*(opus_val32)(b))
#define MAC16_16(c,a,b) ((c)+(opus_val32)(a)*(opus_val32)(b))
--- a/celt/fixed_debug.h
+++ b/celt/fixed_debug.h
@@ -59,6 +59,12 @@
#define SHR(a,b) SHR32(a,b)
#define PSHR(a,b) PSHR32(a,b)
+/** Add two 32-bit values, ignore any overflows */
+#define ADD32_ovflw(a,b) (celt_mips+=2,(opus_val32)((opus_uint32)(a)+(opus_uint32)(b)))
+/** Subtract two 32-bit values, ignore any overflows */
+#define SUB32_ovflw(a,b) (celt_mips+=2,(opus_val32)((opus_uint32)(a)-(opus_uint32)(b)))
+#define NEG32_ovflw(a) (celt_mips+=2,(opus_val32)(-(opus_uint32)(a)))
+
static OPUS_INLINE short NEG16(int x)
{int res;
--- a/celt/fixed_generic.h
+++ b/celt/fixed_generic.h
@@ -117,6 +117,12 @@
/** Subtract two 32-bit values */
#define SUB32(a,b) ((opus_val32)(a)-(opus_val32)(b))
+/** Add two 32-bit values, ignore any overflows */
+#define ADD32_ovflw(a,b) ((opus_val32)((opus_uint32)(a)+(opus_uint32)(b)))
+/** Subtract two 32-bit values, ignore any overflows */
+#define SUB32_ovflw(a,b) ((opus_val32)((opus_uint32)(a)-(opus_uint32)(b)))
+#define NEG32_ovflw(a) ((opus_val32)(-(opus_uint32)(a)))
+
/** 16x16 multiplication where the result fits in 16 bits */
#define MULT16_16_16(a,b) ((((opus_val16)(a))*((opus_val16)(b))))
--- a/celt/kiss_fft.c
+++ b/celt/kiss_fft.c
@@ -82,8 +82,8 @@
C_SUB( Fout2[0] , Fout[0] , t );
C_ADDTO( Fout[0] , t );
- t.r = S_MUL(Fout2[1].r+Fout2[1].i, tw);
- t.i = S_MUL(Fout2[1].i-Fout2[1].r, tw);
+ t.r = S_MUL(ADD32_ovflw(Fout2[1].r, Fout2[1].i), tw);
+ t.i = S_MUL(SUB32_ovflw(Fout2[1].i, Fout2[1].r), tw);
C_SUB( Fout2[1] , Fout[1] , t );
C_ADDTO( Fout[1] , t );
@@ -92,8 +92,8 @@
C_SUB( Fout2[2] , Fout[2] , t );
C_ADDTO( Fout[2] , t );
- t.r = S_MUL(Fout2[3].i-Fout2[3].r, tw);
- t.i = S_MUL(-Fout2[3].i-Fout2[3].r, tw);
+ t.r = S_MUL(SUB32_ovflw(Fout2[3].i, Fout2[3].r), tw);
+ t.i = S_MUL(NEG32_ovflw(ADD32_ovflw(Fout2[3].i, Fout2[3].r)), tw);
C_SUB( Fout2[3] , Fout[3] , t );
C_ADDTO( Fout[3] , t );
Fout += 8;
@@ -126,10 +126,10 @@
C_ADDTO( *Fout , scratch1 );
C_SUB( scratch1 , Fout[1] , Fout[3] );
- Fout[1].r = scratch0.r + scratch1.i;
- Fout[1].i = scratch0.i - scratch1.r;
- Fout[3].r = scratch0.r - scratch1.i;
- Fout[3].i = scratch0.i + scratch1.r;
+ Fout[1].r = ADD32_ovflw(scratch0.r, scratch1.i);
+ Fout[1].i = SUB32_ovflw(scratch0.i, scratch1.r);
+ Fout[3].r = SUB32_ovflw(scratch0.r, scratch1.i);
+ Fout[3].i = ADD32_ovflw(scratch0.i, scratch1.r);
Fout+=4;
}
} else {@@ -160,10 +160,10 @@
tw3 += fstride*3;
C_ADDTO( *Fout , scratch[3] );
- Fout[m].r = scratch[5].r + scratch[4].i;
- Fout[m].i = scratch[5].i - scratch[4].r;
- Fout[m3].r = scratch[5].r - scratch[4].i;
- Fout[m3].i = scratch[5].i + scratch[4].r;
+ Fout[m].r = ADD32_ovflw(scratch[5].r, scratch[4].i);
+ Fout[m].i = SUB32_ovflw(scratch[5].i, scratch[4].r);
+ Fout[m3].r = SUB32_ovflw(scratch[5].r, scratch[4].i);
+ Fout[m3].i = ADD32_ovflw(scratch[5].i, scratch[4].r);
++Fout;
}
}
@@ -212,18 +212,18 @@
tw1 += fstride;
tw2 += fstride*2;
- Fout[m].r = Fout->r - HALF_OF(scratch[3].r);
- Fout[m].i = Fout->i - HALF_OF(scratch[3].i);
+ Fout[m].r = SUB32_ovflw(Fout->r, HALF_OF(scratch[3].r));
+ Fout[m].i = SUB32_ovflw(Fout->i, HALF_OF(scratch[3].i));
C_MULBYSCALAR( scratch[0] , epi3.i );
C_ADDTO(*Fout,scratch[3]);
- Fout[m2].r = Fout[m].r + scratch[0].i;
- Fout[m2].i = Fout[m].i - scratch[0].r;
+ Fout[m2].r = ADD32_ovflw(Fout[m].r, scratch[0].i);
+ Fout[m2].i = SUB32_ovflw(Fout[m].i, scratch[0].r);
- Fout[m].r -= scratch[0].i;
- Fout[m].i += scratch[0].r;
+ Fout[m].r = SUB32_ovflw(Fout[m].r, scratch[0].i);
+ Fout[m].i = ADD32_ovflw(Fout[m].i, scratch[0].r);
++Fout;
} while(--k);
@@ -282,22 +282,22 @@
C_ADD( scratch[8],scratch[2],scratch[3]);
C_SUB( scratch[9],scratch[2],scratch[3]);
- Fout0->r += scratch[7].r + scratch[8].r;
- Fout0->i += scratch[7].i + scratch[8].i;
+ Fout0->r = ADD32_ovflw(Fout0->r, ADD32_ovflw(scratch[7].r, scratch[8].r));
+ Fout0->i = ADD32_ovflw(Fout0->i, ADD32_ovflw(scratch[7].i, scratch[8].i));
- scratch[5].r = scratch[0].r + S_MUL(scratch[7].r,ya.r) + S_MUL(scratch[8].r,yb.r);
- scratch[5].i = scratch[0].i + S_MUL(scratch[7].i,ya.r) + S_MUL(scratch[8].i,yb.r);
+ scratch[5].r = ADD32_ovflw(scratch[0].r, ADD32_ovflw(S_MUL(scratch[7].r,ya.r), S_MUL(scratch[8].r,yb.r)));
+ scratch[5].i = ADD32_ovflw(scratch[0].i, ADD32_ovflw(S_MUL(scratch[7].i,ya.r), S_MUL(scratch[8].i,yb.r)));
- scratch[6].r = S_MUL(scratch[10].i,ya.i) + S_MUL(scratch[9].i,yb.i);
- scratch[6].i = -S_MUL(scratch[10].r,ya.i) - S_MUL(scratch[9].r,yb.i);
+ scratch[6].r = ADD32_ovflw(S_MUL(scratch[10].i,ya.i), S_MUL(scratch[9].i,yb.i));
+ scratch[6].i = NEG32_ovflw(ADD32_ovflw(S_MUL(scratch[10].r,ya.i), S_MUL(scratch[9].r,yb.i)));
C_SUB(*Fout1,scratch[5],scratch[6]);
C_ADD(*Fout4,scratch[5],scratch[6]);
- scratch[11].r = scratch[0].r + S_MUL(scratch[7].r,yb.r) + S_MUL(scratch[8].r,ya.r);
- scratch[11].i = scratch[0].i + S_MUL(scratch[7].i,yb.r) + S_MUL(scratch[8].i,ya.r);
- scratch[12].r = - S_MUL(scratch[10].i,yb.i) + S_MUL(scratch[9].i,ya.i);
- scratch[12].i = S_MUL(scratch[10].r,yb.i) - S_MUL(scratch[9].r,ya.i);
+ scratch[11].r = ADD32_ovflw(scratch[0].r, ADD32_ovflw(S_MUL(scratch[7].r,yb.r), S_MUL(scratch[8].r,ya.r)));
+ scratch[11].i = ADD32_ovflw(scratch[0].i, ADD32_ovflw(S_MUL(scratch[7].i,yb.r), S_MUL(scratch[8].i,ya.r)));
+ scratch[12].r = SUB32_ovflw(S_MUL(scratch[9].i,ya.i), S_MUL(scratch[10].i,yb.i));
+ scratch[12].i = SUB32_ovflw(S_MUL(scratch[10].r,yb.i), S_MUL(scratch[9].r,ya.i));
C_ADD(*Fout2,scratch[11],scratch[12]);
C_SUB(*Fout3,scratch[11],scratch[12]);
--- a/celt/mdct.c
+++ b/celt/mdct.c
@@ -270,8 +270,8 @@
int rev;
kiss_fft_scalar yr, yi;
rev = *bitrev++;
- yr = S_MUL(*xp2, t[i]) + S_MUL(*xp1, t[N4+i]);
- yi = S_MUL(*xp1, t[i]) - S_MUL(*xp2, t[N4+i]);
+ yr = ADD32_ovflw(S_MUL(*xp2, t[i]), S_MUL(*xp1, t[N4+i]));
+ yi = SUB32_ovflw(S_MUL(*xp1, t[i]), S_MUL(*xp2, t[N4+i]));
/* We swap real and imag because we use an FFT instead of an IFFT. */
yp[2*rev+1] = yr;
yp[2*rev] = yi;
@@ -301,8 +301,8 @@
t0 = t[i];
t1 = t[N4+i];
/* We'd scale up by 2 here, but instead it's done when mixing the windows */
- yr = S_MUL(re,t0) + S_MUL(im,t1);
- yi = S_MUL(re,t1) - S_MUL(im,t0);
+ yr = ADD32_ovflw(S_MUL(re,t0), S_MUL(im,t1));
+ yi = SUB32_ovflw(S_MUL(re,t1), S_MUL(im,t0));
/* We swap real and imag because we're using an FFT instead of an IFFT. */
re = yp1[1];
im = yp1[0];
@@ -312,8 +312,8 @@
t0 = t[(N4-i-1)];
t1 = t[(N2-i-1)];
/* We'd scale up by 2 here, but instead it's done when mixing the windows */
- yr = S_MUL(re,t0) + S_MUL(im,t1);
- yi = S_MUL(re,t1) - S_MUL(im,t0);
+ yr = ADD32_ovflw(S_MUL(re,t0), S_MUL(im,t1));
+ yi = SUB32_ovflw(S_MUL(re,t1), S_MUL(im,t0));
yp1[0] = yr;
yp0[1] = yi;
yp0 += 2;
@@ -333,8 +333,8 @@
kiss_fft_scalar x1, x2;
x1 = *xp1;
x2 = *yp1;
- *yp1++ = MULT16_32_Q15(*wp2, x2) - MULT16_32_Q15(*wp1, x1);
- *xp1-- = MULT16_32_Q15(*wp1, x2) + MULT16_32_Q15(*wp2, x1);
+ *yp1++ = SUB32_ovflw(MULT16_32_Q15(*wp2, x2), MULT16_32_Q15(*wp1, x1));
+ *xp1-- = ADD32_ovflw(MULT16_32_Q15(*wp1, x2), MULT16_32_Q15(*wp2, x1));
wp1++;
wp2--;
}