olap_add.asm

基于tms320vc55*系列DSP常用算法

;
;    olap_add.asm - Routine to perform overlap and add operation
;
;    Protptye: void olap_add(complex *, int *, unsigned int, unsigned int, unsigned int);
;
;    Entry: arg0: AR0 is the pointer to X[]
;           arg1: AR1 is the pointer to OVRLAP[]
;           arg2: T0  is the number of filter coefficients, L
;           arg3: T1  is the number of data samples, M
;           arg4: AR2 is the bin numbers of the FFT, N

	.global	_olap_add
	.sect	"fft_code"
	
_olap_add:
    sub  #2,T0
    mov  T0,BRC0         ; BRC0 = L-2
    mov  T0,CSR          ; CSR = L-2
    mov  XAR0,XAR4
    mov  XAR1,XAR3   
||  rptblocal olap_add-1 ; for (i=0; i<L-1; i++)
    mov  dbl(*AR4),AC0   ;    X[i].re += OVRLAP[i];
    add  *AR3+ <<#16,AC0
    mov  AC0,dbl(*AR4+)
olap_add

    sfts T1,#1 
    add  T1,AR0
    mov  #2,T0       
||  rpt  CSR             ; for (k=0, i=M; i<N; i++)
    mov  *(AR0+T0),*AR1+ ;    OVRLAP[k++] = X[i].re;
 
    ret
    .end