fir.asm

等波纹方法设计的FIR滤波器

	.title"fir.asm"
	.mmregs
	.global	_c_int00       
size	.set	14
x_new	.usect	"NewData",	14
x_old	.usect	"OldData",	14
        .bss    y,1
	.bss    count, 1
	.bss    out,14
	.bss    in,14
	.data
COEF:   .word   0037h        
        .word   0FD12h
        .word   0408h
        .word   0FE98h
        .word   0FD22h
        .word   029Fh
        .word   02C0h
     	.word   0FB19h
    	.word   0FE36h
        .word   086Fh
    	.word   0FEBFh
    	.word   0F0C5h
    	.word   0CDDh
    	.word   3ED2h
input:      .word 0x7FFF
            .word 0x0000
            .word 0x0000
            .word 0x0000
            .word 0x0000
            .word 0x0000
            .word 0x0000
            .word 0x0000
            .word 0x0000
            .word 0x0000
            .word 0x0000
            .word 0x0000
            .word 0x0000
            .word 0x0000
            
	.text
_c_int00:
    stm #in,ar2
    rpt #13
    mvpd input,*ar2+
	ld	#0,	a
	stm	#x_new,	ar2
	rpt	#13
	stl	a,	*ar2+
	stm	#x_old,	ar2
	rpt	#13
	stl	a,	*ar2+   ;清零
	ld	#y,	DP
	st	#0,	*(count)
	ssbx 	frct		;小数乘法
	stm	#size,	bk
	stm	#-1,	ar0
	stm	#x_new,	ar2
	stm	#x_old+(size-1),ar3
    stm #out, ar1
    stm #in,ar4
	mvdd *ar4+,	*ar2
FIR:	add	*ar2+0%,  *ar3+0%,  a
	rptz	b,	#(size-1)
	firs	*ar2+0%,  *ar3+0%,  COEF
        ld      #0   ,a	
	sth	b,	*ar1+
	mar	*+ar2(2)%
	nop
	mar	*ar3+%
	mvdd	*ar2,	*ar3+0%	
	addm	#1,	*(count)
	cmpm	*(count),14
	bc	done,	tc
	bd	FIR
	mvdd *ar4+,	*ar2
	nop
done:	b	done

	.end