基于DSP实现FIR滤波器实验解答

主频80MHZ，晶振20MHZ，定时125us,4阶滤波器，0.1，0.2，-0.1，-0.2,端口4进8出实现：
asm程序

            .title            "FIR.asm"
            .mmregs
            .def            _c_int00
STACK        .usect            "stk",10H
            .sect            "vectors"
x            .usect            "x",4
h            .usect            "h",4
            .bss            y,1
PA4            .set            4
PA8            .set            8
            .data
table        .word              1*32768/10
            .word              2*32768/10
            .word              -1*32768/10
            .word              -2*32768/10
            .text
_c_int00:   LD                #0006h,DP
            STM             #STACK+10H,SP
            SSBX            INTM
            RSBX            SXM
            STM             #0825H,PMST
            STM             #0669H,TCR
            STM             #3007H,CLKMD
            STM             #999,PRD
            STM             #008H,IMR
            STM             #0FFFH,IFR
            SSBX            FRCT
            STM             #h,AR2
            RPT             #3
            MVPD            table,*AR2+
            STM             #y,AR5
            STM             #x+3,AR1
            STM             #h+3,AR2
            STM             #3,AR0
            STM             #x,AR4
FIR:        PORTR           PA4,*AR3
            LD              *AR1-,T
            MPY             *AR2-,A            ;4
            LTD             *AR1-
            MAC             *AR2-,A            ;3
            LTD             *AR1-
            MAC             *AR2-,A            ;2    
            LTD             *AR1+0
            MAC             *AR2+0,A        ;1
            STH             A,*AR5
            PORTW           *AR5,PA8
            RETE
loop:        B                loop
            B               _c_int00
            nop
            nop
NMT            rete
            nop
            nop
            nop
SINT17      .space          4*14*16
TIN0:       rsbx            intm
            rete
            NOP
            NOP
           .space          4*18*16
TINT:       B               FIR
            nop
            nop
            .end

cmd文件

MEMORY
{PAGE 0:        VECS:                origin=0800H,length=0500H
                PROG:                origin=1600H,length=0500H
                DATA:                origin=2400H,length=0500H
 PAGE 1:        BSS:                 origin=0300H,length=0200H
                XSPACE:              origin=0500H,length=0010H
                HSPACE:              origin=0510H,length=0010H
                STACK:               origin=0600H,length=0500H
}
SECTIONS
{               .data     :>DATA              PAGE 0
                .text     :>PROG              PAGE 0
                vector    :>VECS              PAGE 0
                .bss      :>BSS               PAGE 1
                x         :>XSPACE            PAGE 1
                h         :>HSPACE            PAGE 1
                .stk      :>STACK             PAGE 1
}

实验现象：

波形：