lsp_lpc.asm

TI C54写的G729代码,视线8kbps高质量语音编码,汇编优化

;==========================================================================
;  File Name
;  ----------
;  LSP_INTP.ASM
;
;  Brief Description of the Code:
;  ------------------------------
;  Compute the LPC coefficients from lsp (order=10)
;
;  Ref
;  ------
;  LPCFUNC.C
;==========================================================================
; Procedure Lsp_Az:
;           ~~~~~~
; Compute the LPC coefficients from lsp (order=10)
;---------------------------------------------------------------------
;  Lsp_Az
;---------------------------------------------------------------------
;  void Lsp_Az(
;    Word16 lsp[],    /* (i) Q15 : line spectral frequencies            */
;    Word16 a[]       /* (o) Q12 : predictor coefficients (order = 10)  */
;  )
;---------------------------------------------------------------------
;               C code          Asm code
;               ------          --------
;               a[0] = 1        skip
;               a[1]       =    a[0]
;               a[2]       =    a[1]
;                 :        :      :
;               a[10]      =    a[9]
;---------------------------------------------------------------------
;  Pointers  : ptr_Az -> a
;              ptr_lsp_coef -> lsp
;
;  Modified Registers: AR2, AR3, AR4, AR5
;
;  Note : No saturate and rounding
;---------------------------------------------------------------------
		.mmregs
        .include ..\include\const.h
        .include ..\include\ld8amem.h

        .text
        .def     lsp_lpc
        
        .ref     Get_lsp_pol

        .asg     "AR2", pf1
        .asg     "AR3", pf2
        .asg     "AR4", pLpcCoef1
        .asg     "AR5", pLpcCoef2

        .asg     "Addr_local_buf1", f1
        .asg     "Addr_local_buf1+16", f2
        .asg     "ptr_lsp_coef", pLsp
        .asg     "ptr_Az", pAz

lsp_lpc:
        STM     #f1, AR2
        STM     #f2, AR3
        CALLD   Get_lsp_pol
        MVDM    #pLsp, AR4


        MVDM    ptr_Az, pLpcCoef2
        STM     #5-1, BRC
        MAR     *pLpcCoef2+0                  ; AR0 = 4
        MVMM    pLpcCoef2, pLpcCoef1
        MAR     *pLpcCoef2+

        STM     #f1 + 10, pf1                 ; pf1 -> &f1[5]

        RPTBD   BLK_END-1
        STM     #f2 + 10, pf2                 ; pf2 -> &f2[5]

                DLD      *pf1-, A
                DADD     *pf1,  A
                DLD      *pf2-, B
                DSUB     *pf2, B

                ADD      #1, 12, A            ; rounding

                ADD      B, A
                STL      A, -13, *pLpcCoef1-
                SUB      B, 1, A
                STL      A, -13, *pLpcCoef2+
BLK_END
        RET