examplehpf.s

dsPIC30F Code ——学习PIC单片机（16位）的好资料

; ..............................................................................
;    File   ExampleHPF.s
; ..............................................................................

		.equ ExampleHPFNumSections, 5

; ..............................................................................
;
; Allocate and initialize filter coefficients
;
; These coefficients have been designed for use in the Transpose filter only

		.section .xdata

ExampleHPFCoefs:
.hword	0x2392	; b( 1,0)/2
.hword	0xB8FF	; b( 1,1)/2
.hword	0x3D5F	; a( 1,1)/2
.hword	0x2392	; b( 1,2)/2
.hword	0xEF39	; a( 1,2)/2
.hword	0x2FBB	; b( 2,0)/2
.hword	0xA1F2	; b( 2,1)/2
.hword	0x579D	; a( 2,1)/2
.hword	0x2FBB	; b( 2,2)/2
.hword	0xDA17	; a( 2,2)/2
.hword	0x3818	; b( 3,0)/2
.hword	0x9344	; b( 3,1)/2
.hword	0x68F9	; a( 3,1)/2
.hword	0x3818	; b( 3,2)/2
.hword	0xCC0D	; a( 3,2)/2
.hword	0x3C51	; b( 4,0)/2
.hword	0x8C80	; b( 4,1)/2
.hword	0x7150	; a( 4,1)/2
.hword	0x3C51	; b( 4,2)/2
.hword	0xC52E	; a( 4,2)/2
.hword	0x3E73	; b( 5,0)/2
.hword	0x8920	; b( 5,1)/2
.hword	0x7583	; a( 5,1)/2
.hword	0x3E73	; b( 5,2)/2
.hword	0xC175	; a( 5,2)/2

; ..............................................................................
; Allocate states buffers in (uninitialized) Y data space

		.section .ybss,  "b"

ExampleHPFStates1:
		.space ExampleHPFNumSections*2

ExampleHPFStates2:
		.space ExampleHPFNumSections*2

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

		.section .data
		.global _ExampleHPFFilter

_ExampleHPFFilter:
.hword ExampleHPFNumSections-1
.hword ExampleHPFCoefs
.hword 0xFF00
.hword ExampleHPFStates1
.hword ExampleHPFStates2
.hword 0x0000

; ..............................................................................
; Sample assembly language calling program
;  The following declarations can be cut and pasted as needed into a program
;		.extern	_IIRTransposeFilterInit
;		.extern	_BlockIIRTransposeFilter
;		.extern	_ExampleHPFFilter
;
;		.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	#_ExampleHPFFilter, W0	; Initalize W0 to filter structure
;		call	_IIRTransposeFilterInit	; call this function once
;
; The next 4 instructions are required prior to each subroutine call
; to _BlockIIRTransposeFilter
;		mov	#_ExampleHPFFilter, 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	_BlockIIRTransposeFilter	; call as many times as needed