pre_pole.asm

利用G.723协议在DSP实现音频信号的压缩与解压缩实验

;-------------------------------------------------------------------
; * predictor_pole()
; *
; * computes the estimated signal from 2-pole predictor.
; *
; */
;int
;predictor_pole(
;	struct g723_state *state_ptr)
;{
;	return (fmult(state_ptr->a[1] >> 2, state_ptr->sr[1]) +
;	    fmult(state_ptr->a[0] >> 2, state_ptr->sr[0]));
;}
;/*-----------------------------------------------------------------
             .title   "pre_pole.asm"
             .include "g723_global.asm"
             .include "g723tab_h.asm"
             .include "g723_stat.asm"
             
             .mmregs
             .text
predictor_pole:
        
        mvmm   AR7, AR4
        mar    *+AR4(a+1)
        mvmm   AR7, AR5
        mar    *+AR5(sr+1)
        stm    #2-1, AR3
        st     #0, *AR0
accum2:        
        pshm   AR3
       
        ld     *AR5-, B
        calld   fmult
        ld     *AR4-, -2, A
         
        add    *AR0, A
        popm   AR3   
        stl    A, *AR0
        banz   accum2, *AR3-
        
        ret     ;返回值=A=*AR0      
            
             .end