Texas Instruments TMS320C64X - Manual (Page 71)

DSP_fir_gen
4-43 C64x+ DSPLIB Reference
Special Requirements
- The number of coefficients, nh, must be greater than or equal to 5.
Coefficients must be in reverse order.
- The number of outputs computed, nr, must be a multiple of 4 and greater
than or equal to 4.
- Array r[ ] must be word aligned.
Implementation Notes
- Bank Conflicts: No bank conflicts occur.
- Interruptibility: The code is interrupt-tolerant but not interruptible.
- Load double-word instruction is used to simultaneously load four values
in a single clock cycle.
- The inner loop is unrolled four times and will always compute a multiple
of 4 of nh and nr. If nh is not a multiple of 4, the code will fill in zeros to make
nh a multiple of 4.
- This code yields best performance when the ratio of outer loop to inner
loop is less than or equal to 4.
Benchmarks Cycles: Not available
Codesize: Not available