syn_ap1.asm

TI C54写的G729代码,视线8kbps高质量语音编码,汇编优化

;=====================================================
; File Name
; -------------
; syn_ap1.asm
;
; Bridf Description of the Code:
; -------------------------------
; Compute the coefficients of synthese filter
;
; Ref
; ---------
; COD_LD8A.C
;======================================================
        .mmregs
        .include  ../include/const.h
        .include  ../include/tab_ld8a.h
        .include  ../include/ld8amem.h

        .text
        .def      Syn_ap1

;------------------------------------------------------
; Syn_ap1
;------------------------------------------------------
; ap = Ap_t
; ap1[i] = Ap[i] - 0.7 * Ap[i-1]  i = 1 --> M
;------------------------------------------------------
;  Points : ptr_bi --> Ap_t  (i)
;           ptr_ap1 --> ap1  (o)
;
;  Input Registres : BRC = M - 1
;------------------------------------------------------

        .asg    "AR3", pBi
        .asg    "AR4", pAp1

Syn_ap1:

		MVDM ptr_bi,AR2
        ST      #4096, *pBi+
        ST      #4096, *pAp1+
        ST      #22938, *AR2

        RPTB    EndSyn_ap1 - 1

                LD     *AR3-, 16, B
                ADD     #1, 15, B                ;rounting
                LD      *AR3, 16, A
                BC      L0, AEQ
                MAS     *AR2, *AR3, B
                ADD     #1, 15, B                ;rounting
                SAT     B
L0:             STL     B, -16, *pAp1+
                MAR     *+AR3(2)
EndSyn_ap1:

        RET