intpl3.asm

TI C54写的G729代码,视线8kbps高质量语音编码,汇编优化

;==========================================================================
;  File Name
;  ----------
;  INTPL3.ASM
;
;  Brief Description of the Code:
;  ------------------------------
;  For interpolating the normalized correlation with 1/3 resolution.
;
;  Ref
;  ------
;  PITCH.C
;==========================================================================
;  Interpol_3
;---------------------------------------------------------------------------
;  Word16 Interpol_3(      /* (o)  : interpolated value  */
;    Word16 *x,            /* (i)  : input vector        */
;    Word16 frac           /* (i)  : fraction            */
;  )
;---------------------------------------------------------------------------
;  Input : ptr_xn -> x
;          A = frac (low 16 bits)
;
;  Outpur: A = Interpol_3
;
;  Modified Registers : AR0, AR2, AR3, AR4, AR5, BRC
;---------------------------------------------------------------------------
		.mmregs
        .include ..\include\const.h
        .include ..\include\ld8amem.h
        .include ..\include\tab_ld8a.h

        .text
        .def     Interpol_3

        .ref     ptr_xn

        .asg     "AR2", pX1
        .asg     "AR3", pX2
        .asg     "AR4", pC1
        .asg     "AR5", pC2

Interpol_3:
        STM     #0, BK
        LD      #UP_SAMP, B
        STLM    B, AR0
        MVDM    ptr_xn, pX1
        XC      2, ALT
                ADD     B, A
                MAR     *pX1-
        MVMM    pX1, pX2
        MAR     *pX2+
        SUB     A, B
        ADD     #Intpl_3, A
        STLM    A, pC1
        ADD     #Intpl_3, B

        STM     #L_INTER4-1, BRC
        RPTBD   BLK_END-1
        STLM    B, pC2
        LD      #0, A

                MAC     *pX1-, *pC1+0%, A
                MAC     *pX2+, *pC2+0%, A
BLK_END
        RET