firlpf3000.s

a good project in embedded system

; ..............................................................................
;    File   firLPF3000.s
; ..............................................................................

		.equ firLPF3000NumTaps, 61

; ..............................................................................
; Allocate and initialize filter taps

		.section .firLPF3000const, "x"
		.align 128

firLPF3000Taps:
.hword 	0xFFED,	0xFFFE,	0x0026,	0xFFBA,	0x0050,	0xFFCF,	0xFFED,	0x006A,	0xFF56
.hword 	0x00AC,	0xFFA9,	0xFFBE,	0x00EE,	0xFEA7,	0x013F,	0xFF7F,	0xFF51,	0x01E7
.hword 	0xFD71,	0x0231,	0xFF59,	0xFE51,	0x0401,	0xFACD,	0x0449,	0xFF3F,	0xFADE
.hword 	0x0C5D,	0xECA9,	0x1865,	0x64F8,	0x1865,	0xECA9,	0x0C5D,	0xFADE,	0xFF3F
.hword 	0x0449,	0xFACD,	0x0401,	0xFE51,	0xFF59,	0x0231,	0xFD71,	0x01E7,	0xFF51
.hword 	0xFF7F,	0x013F,	0xFEA7,	0x00EE,	0xFFBE,	0xFFA9,	0x00AC,	0xFF56,	0x006A
.hword 	0xFFED,	0xFFCF,	0x0050,	0xFFBA,	0x0026,	0xFFFE,	0xFFED

; ..............................................................................
; Allocate delay line in (uninitialized) Y data space

		.section .ybss,  "b"
		.align 128

firLPF3000Delay:
		.space firLPF3000NumTaps*2

; ..............................................................................
; Allocate and intialize filter structure

		.section .data
		.global _firLPF3000Filter

_firLPF3000Filter:
.hword firLPF3000NumTaps
.hword psvoffset(firLPF3000Taps)
.hword psvoffset(firLPF3000Taps)+firLPF3000NumTaps*2-1
.hword psvpage(firLPF3000Taps)
.hword firLPF3000Delay
.hword firLPF3000Delay+firLPF3000NumTaps*2-1
.hword firLPF3000Delay

; ..............................................................................
; ..............................................................................
; Sample assembly language calling program
;  The following declarations can be cut and pasted as needed into a program
;		.extern	_FIRFilterInit
;		.extern	_BlockFIRFilter
;		.extern	_firLPF3000Filter
;
;		.section	.bss
;
;	 The input and output buffers can be made any desired size
;	   the value 40 is just an example - however, one must ensure
;	   that the output buffer is at least as long as the number of samples
;	   to be filtered (parameter 4)
;input:		.space	40
;output:	.space	40
;		.text
;
;
;  This code can be copied and pasted as needed into a program
;
;
; Set up pointers to access input samples, filter taps, delay line and
; output samples.
;		mov	#_firLPF3000Filter, W0	; Initalize W0 to filter structure
;		call	_FIRFilterInit	; call this function once
;
; The next 4 instructions are required prior to each subroutine call
; to _BlockFIRFilter
;		mov	#_firLPF3000Filter, W0	; Initalize W0 to filter structure
;		mov	#input, W1	; Initalize W1 to input buffer 
;		mov	#output, W2	; Initalize W2 to output buffer
;		mov	#20, W3	; Initialize W3 with number of required output samples
;		call	_BlockFIRFilter	; call as many times as needed