@//
@//  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
@//
@//  Use of this source code is governed by a BSD-style license
@//  that can be found in the LICENSE file in the root of the source
@//  tree. An additional intellectual property rights grant can be found
@//  in the file PATENTS.  All contributing project authors may
@//  be found in the AUTHORS file in the root of the source tree.
@//
@//  This file was originally licensed as follows. It has been
@//  relicensed with permission from the copyright holders.
@//

@//
@// File Name:  armSP_FFT_CToC_SC32_Radix2_unsafe_s.s
@// OpenMAX DL: v1.0.2
@// Last Modified Revision:   5638
@// Last Modified Date:       Wed, 06 Jun 2007
@// 
@// (c) Copyright 2007-2008 ARM Limited. All Rights Reserved.
@// 
@// 
@//
@// Description:
@// Compute a Radix 2 DIT in-order out-of-place FFT stage for a N point complex signal.
@// This handle the general stage, not the first or last stage.
@// 

        
@// Include standard headers

#include "omxtypes_s.h"
#include "armCOMM_s.h"
        
        
@// Import symbols required from other files
@// (For example tables)

           
@// Set debugging level        
@//DEBUG_ON    SETL {TRUE}


@// Guarding implementation by the processor name
    
    
@// Guarding implementation by the processor name
    
    
@//Input Registers

#define pSrc		r0
#define pDst		r2
#define pTwiddle	r1
#define subFFTNum	r6
#define subFFTSize	r7


@//Output Registers


@//Local Scratch Registers

#define outPointStep	r3
#define pointStep	r4
#define grpCount	r5
#define setCount	r8
@//const           RN  9
#define step		r10
#define dstStep		r11
#define pTable		r9
#define pTmp		r9    

@// Neon Registers

#define dW	D0.S32
#define dX0	D2.S32
#define dX1	D3.S32
#define dX2	D4.S32
#define dX3	D5.S32
#define dY0	D6.S32
#define dY1	D7.S32
#define dY2	D8.S32
#define dY3	D9.S32
#define qT0	Q3.S64
#define qT1	Q4.S64

    
        .MACRO FFTSTAGE scaled, inverse, name
        
        @// Define stack arguments
        
        
        @// Update grpCount and grpSize rightaway inorder to reuse pGrpCount and pGrpSize regs
        
        LSR     subFFTNum,subFFTNum,#1                      @//grpSize
        LSL     grpCount,subFFTSize,#1
        
        
        @// pT0+1 increments pT0 by 8 bytes
        @// pT0+pointStep = increment of 8*pointStep bytes = 4*grpSize bytes
        MOV     pointStep,subFFTNum,LSL #2
        
        @// update subFFTSize for the next stage
        MOV     subFFTSize,grpCount
        
        @// pOut0+1 increments pOut0 by 8 bytes
        @// pOut0+outPointStep == increment of 8*outPointStep bytes = 4*size bytes
        SMULBB  outPointStep,grpCount,pointStep  
        LSL     pointStep,pointStep,#1    
                               
        
        RSB      step,pointStep,#16
        RSB      dstStep,outPointStep,#16
        
        @// Loop on the groups

grpLoop\name :	        
        MOV      setCount,pointStep,LSR #3
        VLD1     dW,[pTwiddle],pointStep                @//[wi | wr]
        
        
        @// Loop on the sets
        
        
setLoop\name :	       
        
        
        VLD2    {dX0,dX1},[pSrc],pointStep            @// point0: dX0-real part dX1-img part
        VLD2    {dX2,dX3},[pSrc],step                 @// point1: dX2-real part dX3-img part
        
        SUBS    setCount,setCount,#2               
        
        .ifeqs  "\inverse", "TRUE"
            VMULL   qT0,dX2,dW[0]
            VMLAL   qT0,dX3,dW[1]                       @// real part
            VMULL   qT1,dX3,dW[0]
            VMLSL   qT1,dX2,dW[1]                       @// imag part
                
        .else
        
            VMULL   qT0,dX2,dW[0]
            VMLSL   qT0,dX3,dW[1]                       @// real part
            VMULL   qT1,dX3,dW[0]
            VMLAL   qT1,dX2,dW[1]                       @// imag part
                    
        .endif
        
        VRSHRN  dX2,qT0,#31
        VRSHRN  dX3,qT1,#31
        
        .ifeqs "\scaled", "TRUE"
            VHSUB    dY0,dX0,dX2
            VHSUB    dY1,dX1,dX3
            VHADD    dY2,dX0,dX2
            VHADD    dY3,dX1,dX3
                
        .else
            VSUB    dY0,dX0,dX2
            VSUB    dY1,dX1,dX3
            VADD    dY2,dX0,dX2
            VADD    dY3,dX1,dX3
        
        .endif
        
        VST2    {dY0,dY1},[pDst],outPointStep
        VST2    {dY2,dY3},[pDst],dstStep              @// dstStep = -outPointStep + 16
        
        BGT     setLoop\name
        
        SUBS    grpCount,grpCount,#2               
        ADD     pSrc,pSrc,pointStep
        BGT     grpLoop\name    
        
        
        @// Reset and Swap pSrc and pDst for the next stage     
        MOV     pTmp,pDst
        SUB     pDst,pSrc,outPointStep,LSL #1       @// pDst -= 4*size; pSrc -= 8*size bytes           
        SUB     pSrc,pTmp,outPointStep
        
        @// Reset pTwiddle for the next stage
        SUB     pTwiddle,pTwiddle,outPointStep      @// pTwiddle -= 4*size bytes
        
        
        .endm
        
        
        M_START armSP_FFTFwd_CToC_SC32_Radix2_OutOfPlace_unsafe,r4
        FFTSTAGE "FALSE","FALSE",FWD
        M_END

        
        M_START armSP_FFTInv_CToC_SC32_Radix2_OutOfPlace_unsafe,r4
        FFTSTAGE "FALSE","TRUE",INV
        M_END
 
        
        M_START armSP_FFTFwd_CToC_SC32_Sfs_Radix2_OutOfPlace_unsafe,r4
        FFTSTAGE "TRUE","FALSE",FWDSFS
        M_END

        
        M_START armSP_FFTInv_CToC_SC32_Sfs_Radix2_OutOfPlace_unsafe,r4
        FFTSTAGE "TRUE","TRUE",INVSFS
        M_END

	.end