updt_err.asm

TI C54写的G729代码,视线8kbps高质量语音编码,汇编优化

;==========================================================================
;  File Name
;  ----------
;  UPDT_ERR.ASM
;
;  Brief Description of the Code:
;  ------------------------------
;  Maintains the memory used to compute the error function
;  due to an adaptive codebook mismatch between encoder and decoder
;
;  Ref
;  ------
;  COD_LD8K.C
;==========================================================================
;  Function : update_exc_err
;----------------------------------------------------------------------
;  static void update_exc_err(
;   Word16 gain_pit,      /* (i) pitch gain */
;   Word16 T0             /* (i) integer part of pitch delay */
;  )
;----------------------------------------------------------------------
;  Constants : Addr_T0 -> T0
;              Addr_gain_pit -> gain_pit
;
;  Pointer : ptr_L_exc_err -> L_exc_err
;
;  Modified Registers : AR0, AR4, AR5, DP, BRC
;----------------------------------------------------------------------
        .mmregs
        .include ../include/const.h
        .include ../include/ld8amem.h
        .include ../include/tab_ld8a.h
        .include ../include/qua_gain.h

        .text
        .def     update_exc_err

update_exc_err:
        STM     #0, BK
        LD      #Addr_T0, DP
        LD      #L_SUBFR, A
        SUB     Addr_T0, A
        BCD     Else, ALEQ
        STM     #Addr_gain_pit, AR4

If:
                MVDM    #ptr_L_exc_err, AR5
                LD      #-1, B
                MAR     *AR5+
; MPY32_16 :
                LD       #0, A
                MACSU    *AR5-, *AR4, A
                LD       A, -16, A
                MAC      *AR4, *AR5, A

                LD       A, 1, A
                ADD      #4000h, A
                MAX      B

                STM      #BL, AR5
; MPY32_16 :
                LD       #0, A
                MACSU    *AR5+, *AR4, A
                LD       A, -16, A
                MAC      *AR5, *AR4, A

                LD       A, 1, A
                ADD      #4000h, A

                BD       Next
                MAX      B
                NOP

Else:
; zone1 = tab_zone[n]
                NEG      A
                STLM     A, AR5
                STM      #tab_zone, AR0
                NOP
                MAR      *AR5+0
                LD       *AR5, A        ; A = zone1

; zone2 = tab_zone[i];
                MVDM     Addr_T0, AR5
                NOP
                MAR      *AR5-          ; i = sub(T0, 1)
                MAR      *AR5+0
                LD       *AR5, B        ; B = zone2

                SUB      A, B
                STLM     B, BRC

                LD       #ptr_L_exc_err, DP
                LD       A, 1, A
                ADD      ptr_L_exc_err, A
                STLM     A, AR5
                STM      #3, AR0
                MAR      *AR5+
                RPTBD    BLK1_END-1
                LD       #-1, B

; MPY32_16 :
                         LD       #0, A
                         MACSU    *AR5-, *AR4, A
                         LD       A, -16, A
                         MAC      *AR4, *AR5+0%, A

                         LD       A, 1, A
                         ADD      #4000h, A
                         MAX      B
BLK1_END

Next:
        MVDM    ptr_L_exc_err, AR5
        STM     #4, AR0
        STM     #3-1, BRC
        RPTBD   BLK2_END-1
        MAR     *+AR5(2*2)

                DLD     *AR5+, A
                DST     A, *AR5-0
BLK2_END
        MAR     *+AR5(2)
        DST     B, *AR5
        RET