firlpf1500.s

a good project in embedded system

; ..............................................................................
;    File   firLPF1500.s
; ..............................................................................

		.equ firLPF1500NumTaps, 61

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

		.section .firLPF1500const, "x"
		.align 128

firLPF1500Taps:
.hword 	0x0024,	0x0014,	0xFFD4,	0xFFC6,	0x001E,	0x0069,	0x0014,	0xFF7A,	0xFF96
.hword 	0x0079,	0x00D5,	0xFFDD,	0xFED4,	0xFF83,	0x013F,	0x015A,	0xFF2C,	0xFDC7
.hword 	0xFFCD,	0x02C6,	0x01DE,	0xFD6E,	0xFBFF,	0x0122,	0x0651,	0x023F,	0xF79D
.hword 	0xF66C,	0x09D5,	0x2726,	0x3553,	0x2726,	0x09D5,	0xF66C,	0xF79D,	0x023F
.hword 	0x0651,	0x0122,	0xFBFF,	0xFD6E,	0x01DE,	0x02C6,	0xFFCD,	0xFDC7,	0xFF2C
.hword 	0x015A,	0x013F,	0xFF83,	0xFED4,	0xFFDD,	0x00D5,	0x0079,	0xFF96,	0xFF7A
.hword 	0x0014,	0x0069,	0x001E,	0xFFC6,	0xFFD4,	0x0014,	0x0024

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

		.section .ybss,  "b"
		.align 128

firLPF1500Delay:
		.space firLPF1500NumTaps*2

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

		.section .data
		.global _firLPF1500Filter

_firLPF1500Filter:
.hword firLPF1500NumTaps
.hword psvoffset(firLPF1500Taps)
.hword psvoffset(firLPF1500Taps)+firLPF1500NumTaps*2-1
.hword psvpage(firLPF1500Taps)
.hword firLPF1500Delay
.hword firLPF1500Delay+firLPF1500NumTaps*2-1
.hword firLPF1500Delay

; ..............................................................................
; ..............................................................................
; Sample assembly language calling program
;  The following declarations can be cut and pasted as needed into a program
;		.extern	_FIRFilterInit
;		.extern	_BlockFIRFilter
;		.extern	_firLPF1500Filter
;
;		.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	#_firLPF1500Filter, 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	#_firLPF1500Filter, 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