"TMS320C55x DSP Library DSPLIB Programmer's Reference"

fir2Figure 4–14. x Array in Memoryoldest x( ) entrynewest x( ) entryx(0)x(1)•x(nx–2)x(nx–1)lowest memory addresshighest memory addressFigure 4–15. r Array in Memoryoldest x( ) entrynewest x( ) entryr(0)r(1)•r(nx–2)r(nx–1)lowest memory addresshighest memory addressExampleBenchmarksSee examples/fir subdirectory(preliminary)Cycles † Core: nx * (2 + nh)Overhead: 25Code size(in bytes)107† Assumes all data is in on-chip dual-access RAM and that there is no bus conflict due to twiddletable reads and instruction fetches (provided linker command file reflects those conditions).fir2FunctionBlock FIR Filter (fast)ushort oflag = fir2 (DATA *x, DATA *h, DATA *r, DATA *dbuffer, ushort nx,ushort nh)Argumentsx[nx]r[nx]Pointer to input vector of nx real elements.Pointer to output vector of nx real elements. In-placecomputation (r = x) is allowed.Function Descriptions4-37