Texas Instruments TMS320C64X - Manual (Page 48)

DSP_fft16x16r
4-20
ptr_x2[h2p1] = (yt0 * co2 − xt0 * si2 + 0x00008000) >> 16;
ptr_x2[l2 ] = (xt2 * co3 + yt2 * si3 + 0x00008000) >> 16;
ptr_x2[l2p1] = (yt2 * co3 − xt2 * si3 + 0x00008000) >> 16;
}
tw_offset += fft_jmp;
stride = stride>>2;
} /* end while */
j = offset>>2;
ptr_x0 = ptr_x;
y0 = y;
/* determine _norm(nmax) − 17 */
l0 = 31;
if (((nmax>>31)&1)==1)
num = ~nmax;
else
num = nmax;
if (!num)
l0 = 32;
else
{
a=num&0xFFFF0000; if (a) { l0−=16; num=a; }
a=num&0xFF00FF00; if (a) { l0−= 8; num=a; }
a=num&0xF0F0F0F0; if (a) { l0−= 4; num=a; }
a=num&0xCCCCCCCC; if (a) { l0−= 2; num=a; }
a=num&0xAAAAAAAA; if (a) { l0−= 1; }
}
l0 −= 1;
l0 −= 17;
if(radix == 2 || radix == 4)
for (i = 0; i < n; i += 4)
{
/* reversal computation */
j0 = (j ) & 0x3F;
j1 = (j >> 6) & 0x3F;
k0 = brev[j0];
k1 = brev[j1];