ref: 320347473215dbc128e3aa6fde3749d40e409f32
parent: a536f772028b2ece36178d0d380f242fc8858f0c
author: Jean-Marc Valin <[email protected]>
date: Sat Mar 22 07:23:57 EDT 2008
Using restrict to make it clear there's no aliasing issues in the mdct.
--- a/libcelt/celt.c
+++ b/libcelt/celt.c
@@ -156,7 +156,7 @@
}
/** Apply window and compute the MDCT for all sub-frames and all channels in a frame */
-static celt_word32_t compute_mdcts(const mdct_lookup *lookup, const celt_word16_t * restrict window, celt_sig_t *in, celt_sig_t *out, int N, int overlap, int B, int C)
+static celt_word32_t compute_mdcts(const mdct_lookup *lookup, const celt_word16_t * restrict window, celt_sig_t * restrict in, celt_sig_t * restrict out, int N, int overlap, int B, int C)
{int i, c, N4;
celt_word32_t E = 0;
@@ -171,12 +171,17 @@
for (i=0;i<B;i++)
{int j;
+ celt_word32_t * restrict x1, * restrict x2;
for (j=0;j<2*N-2*N4;j++)
x[j+N4] = in[C*i*N+C*j+c];
+ x1 = x+N4;
+ x2 = x+2*N-N4-1;
for (j=0;j<overlap;j++)
{- x[j+N4] = MULT16_32_Q15(window[j],x[j+N4]);
- x[2*N-j-N4-1] = MULT16_32_Q15(window[j],x[2*N-j-N4-1]);
+ *x1 = MULT16_32_Q15(window[j],*x1);
+ *x2 = MULT16_32_Q15(window[j],*x2);
+ x1++;
+ x2--;
}
for (j=0;j<N4;j++)
{@@ -196,7 +201,7 @@
}
/** Compute the IMDCT and apply window for all sub-frames and all channels in a frame */
-static void compute_inv_mdcts(const mdct_lookup *lookup, const celt_word16_t * restrict window, celt_sig_t *X, celt_sig_t *out_mem, celt_sig_t *mdct_overlap, int N, int overlap, int B, int C)
+static void compute_inv_mdcts(const mdct_lookup *lookup, const celt_word16_t * restrict window, celt_sig_t *X, celt_sig_t * restrict out_mem, celt_sig_t * restrict mdct_overlap, int N, int overlap, int B, int C)
{int i, c, N4;
VARDECL(celt_word32_t, x);
@@ -217,16 +222,11 @@
/* The first and last part would need to be set to zero if we actually
wanted to use them. */
for (j=0;j<overlap;j++)
- {- x[j+N4] = MULT16_32_Q15(window[j],x[j+N4]);
- x[2*N-j-N4-1] = MULT16_32_Q15(window[j],x[2*N-j-N4-1]);
- }
+ out_mem[C*(MAX_PERIOD+(i-B)*N)+C*j+c] = 2*(mdct_overlap[C*j+c]+MULT16_32_Q15(window[j],x[j+N4]));
for (j=0;j<overlap;j++)
- out_mem[C*(MAX_PERIOD+(i-B)*N)+C*j+c] = 2*(x[N4+j]+mdct_overlap[C*j+c]);
+ mdct_overlap[C*(overlap-j-1)+c] = MULT16_32_Q15(window[j],x[2*N-j-N4-1]);
for (j=0;j<2*N4;j++)
out_mem[C*(MAX_PERIOD+(i-B)*N)+C*(j+overlap)+c] = 2*x[j+N4+overlap];
- for (j=0;j<overlap;j++)
- mdct_overlap[C*j+c] = x[N+N4+j];
}
}
RESTORE_STACK;
--- a/libcelt/mdct.c
+++ b/libcelt/mdct.c
@@ -86,7 +86,7 @@
celt_free(l->trig);
}
-void mdct_forward(const mdct_lookup *l, kiss_fft_scalar *in, kiss_fft_scalar *out)
+void mdct_forward(const mdct_lookup *l, kiss_fft_scalar *in, kiss_fft_scalar * restrict out)
{int i;
int N, N2, N4;
@@ -131,7 +131,7 @@
}
-void mdct_backward(const mdct_lookup *l, kiss_fft_scalar *in, kiss_fft_scalar *out)
+void mdct_backward(const mdct_lookup *l, kiss_fft_scalar *in, kiss_fft_scalar * restrict out)
{int i;
int N, N2, N4;