parrocchetto/dsPIC_DSC_G.726A_src/float_annex.s

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;------------------------------------------------------------------------------
;Global Declarations:
;------------------------------------------------------------------------------
        .global _G726_float_ab

;void G726_float_ab(short	sr,short	dq,short	*sr0,short *dq0);

;------------------------------------------------------------------------------
;Code Section in Program Memory
;------------------------------------------------------------------------------ 
        .section libg726a, code

/****************************************************************************
*
*  Function Name:       G726_float_ab    
*
*  System:              RISC
*
*  Platform:            dsPIC33F
*  
*  Description:         Convert 15 or 16 bit signed magnitude to Floating point	  	
*
*  Cycle Count:         39
*
*  Input Parameters:    w0 - sr, w1 - dq, W2 - &state->sr0,W3 - &state->dq0
*
*  Output Parameters:   none
*    
*  History     :
*
*         Date    |        By         |   Remarks
*  ---------------+-------------------+----------------------------------  
*     Oct-21-2005      Sabarinath.P     	        Created.
*     Nov-03-2005      Sabarinath.P     Optimized & Tested ( Cycle : 77 )
*     Nov-07-2005      Sharanabasava M. Modified & Released( Cycle : 47 )
*     Nov-08-2005      Sabarinath.P     Tested & Released  ( Cycle : 44 )
*****************************************************************************/
.text

_G726_float_ab:  
        mov     w0,w4  
        btsc    w0,#15                                     
        neg     w4,w4
        do      #1,CONTINUE
        ff1l    w4,w5                       ;w4-mag
        subr    w5,#17,w5                   ;w6-exp
        btsc    w5,#4
        clr     w5
        cp0     w4
        bra     nz,SHIFT
        mov     #0x20,w4                    ;w7-mant
        bra     OUTP
SHIFT:        
        lac     w4,#-6,A
        sftac   A,w5
        mov     ACCAH,w4
OUTP:
        btsc     w0,#15                               
        neg     w4,w4
        mov     w4,[w2++]                   ;output[cnt] = (short)mant;
        mov     w5,[w2]                     ;output[cnt+2] = exp_;
        mov     w1,w0        
        bclr    w1,#15                      ;mag = dq & 32767;
        mov     w1,w4
CONTINUE:
        mov     w3,w2
        return


;--------End of All Code Sections ---------------------------------------------
.end                               ;End of program code in this file