《基于TI DSP的通用算法实现》程序代码

				
				; Example 5 - 5. BLK FIR Filter ASM Listing for the TMS320C55x DSP
				
				
				******************************************************************************
				* FILE: BFIR_MNE.ASM *
				* DESCRIPTION: Mnemonic C55xx DSP program for block FIR filter. *
				* AUTHOR: David M. Alter, Texas Instruments, Inc. *
				* DATE: February 24, 2000 *
				* RESTRICTIONS: *
				* (1) N_SAMP–N_TAP+1 (the number of output values) must be even. *
				* (2) Overflow is not checked. *
				* (3) Data and coefficients are assumed to be signed Q15 fractions. *
				* (4) The section ”output_data” must be 32–bit aligned in memory. *
				******************************************************************************
				
				
					.def blockfir, rset
					
				N_SAMP 	.set 199 	;# of input samples
				N_TAP 	.set 16 	;# of filter taps
				Q15 	.set 32768 	;Q15 fraction scale value
				
				;Coefficients in Q15 fractional format
					.sect ”coefficients”
					
				a0 	.int Q15*1/32768 ;a0
					.int Q15*15/32768 ;a1
					.int Q15*105/32768 ;a2
					.int Q15*455/32768 ;a3
					.int Q15*1365/32768 ;a4
					.int Q15*3003/32768 ;a5
					.int Q15*5005/32768 ;a6
					.int Q15*6435/32768 ;a7
					.int Q15*6435/32768 ;a8
					.int Q15*5005/32768 ;a9
					.int Q15*3003/32768 ;a10
					.int Q15*1365/32768 ;a11
					.int Q15*455/32768 ;a12
					.int Q15*105/32768 ;a13
					.int Q15*15/32768 ;a14
					.int Q15*1/32768 ;a15
								;Input data in Q15 fractional format
					.sect ”input_data”
				
				x 	.copy dualsine.dat 	;label at oldest input
								;Output array in Q15 fractional format
				y 	.usect ”output_data”, N_SAMP–N_TAP+1, ,1
								;label at oldest output
				
				
				;********** INTERRUPT VECTORS **********
				;This is an incomplete vector table for illustration purposes only
					
					.sect ”vectors”
				rset: 
					.ivec blockfir, USE_RETA 	;reset vector and stack mode
				nmi: 
					.ivec nmi 			;trap spurious NMI’s
				int2: 	.ivec int2 			;trap spurious int2’s
				
				
				;********** FILTER INITIALIZATION **********
				
					.text
				
				blockfir:
				
				;Configure ST1: set SXMD, FRCT
					OR #0000000101000000b, mmap(@ST1_55)
				
				;Configure ST1: clear SATD, C54CM
					AND #1111110111011111b, mmap(ST1_55)
				
				.c54cm_off
				;Configure ST2: clear ARMS. AR1, AR2, and CDP set to linear mode
					AND #0111111011111001b, mmap(ST2_55)
				
					.arms_off
				;Pointer setup
					AMOV #a0, XCDP 					;pointer to coefficient array
					AMOV #(x + N_TAP – 1), XAR0 			;pointer to input vector
					AMOV #(x + N_TAP), XAR1 			;2nd pointer to input vector
					AMOV #y, XAR2 					;pointer to output array
				
				;Other setup
					MOV #((N_SAMP – N_TAP + 1)/2 – 1), BRC0 	;init local repeat counter
					MOV #(–(N_TAP – 1)), T0 			;CDP rewind increment
					MOV #(N_TAP + 1), T1 				;ARx rewind increment
				
				;********** FILTER KERNEL **********
					||RPTBLOCAL end_outer 				;start the outer loop
											;First tap is multiply only (no accumulate)
					MPY *AR0–, *CDP+, AC0
					::MPY *AR1–, *CDP+, AC1
											;Taps 2 through (N_TAPS – 1)
					||RPT #(N_TAP–3) 				;single repeat for inner loop
					MAC *AR0–, *CDP+, AC0
					::MAC *AR1–, *CDP+, AC1
											;Last tap has different pointer increments
					MAC *(AR0+T1), *(CDP+T0), AC0
					::MAC *(AR1+T1), *(CDP+T0), AC1
				end_outer:
					MOV pair(HI(AC0)), dbl(*AR2+) 			;write both results
											;end of outer loop
				;********** PROGRAM TERMINATION **********
				end: 	
					B end 						;trap end of program
											;End of block FIR mnemonic program