www.pudn.com > x28x_FFT.rar > rfft32aq.asm

;============================================================================ 
; 
; File Name     : rfft_acqc.asm 
;  
; Originator    : Advanced Embeeded Control  
;                 Texas Instruments  
;  
; Description   : This file contains to acquire 2N samples and store as N complex valued  
;                 sequence in bit-reversed order                   
;                
; Date          : 26/2/2002 (dd/mm/yyyy) 
;===========================================================================     
; Routine Type  : C Callable         
; 
; Description   : 
; void FFTR_acq(FFTRACQ_handle)  
; This function acquires 2N samples and stores it in a buffer as N-point complex sequence 
; in bit reversed order. This is used for real FFT computation. 
; The buffer should be aligned to 2N words 
;  
;===================================================================== 
; typedef   struct { 
;       int acqflag; 
;       int count; 
;       int size; 
;       int input;  
;       long *tempptr; 
;       long *buffptr; 
;       void (*update)(void *);  
;       }FFTRACQ;   
; 
;====================================================================== 
 
                .def    _RFFT32_acq       ;  
                 
_RFFT32_acq:            
            MOV     ACC,*XAR4++     ; ACC=acqflag 
            SBF     noacq,EQ 
                               
            MOV     ACC,*XAR4++     ; ACC=count 
            SBF     acqover,EQ      ; if count=0, acquisition is complete 
 
            TBIT    *--XAR4,#0      ; if MOD(count,2)==1, set TC 
            DEC     *XAR4           ; count=count-1 
  
            MOVZ    AR0,*+XAR4[7]   ; AR0=size   
            MOVL    XAR5,*+XAR4[3]  ; XAR5=tempptr 
            MOVL    ACC,*+XAR4[1]   ; ACC=input 
 
            BF    oddseq,TC 
            MOVL    *XAR5,ACC       ; *tempptr=input 
noacq:      LRETR 
                                  
oddseq:      
            MOVL    *+XAR5[2],ACC   ; *tempptr=input 
            NOP     *BR0++ 
            MOVL    *+XAR4[3],XAR5 
            LRETR 
     
acqover:    MOV     ACC,*+XAR4[6] 
            MOV     *--XAR4,ACC     ; count=size 
            MOV     *--XAR4,#0      ; acqflag=0 
             
            MOVL    XAR5,*+XAR4[6]  ; XAR5=buffptr 
            MOVL    *+XAR4[4],XAR5  ; tempptr=buffptr 
            LRETR