Add openmax dl routines for review. MUST NOT BE LANDED

third_party/openmax_dl/dl/sp/src/armSP_FFTInv_CCSToR_F32_preTwiddleRadix2_unsafe_s.S

Index: third_party/openmax_dl/dl/sp/src/armSP_FFTInv_CCSToR_F32_preTwiddleRadix2_unsafe_s.S
diff --git a/third_party/openmax_dl/dl/sp/src/armSP_FFTInv_CCSToR_F32_preTwiddleRadix2_unsafe_s.S b/third_party/openmax_dl/dl/sp/src/armSP_FFTInv_CCSToR_F32_preTwiddleRadix2_unsafe_s.S
new file mode 100644
index 0000000000000000000000000000000000000000..f375991f7dd55d0f9126e92dc733b784441e8fa7
--- /dev/null
+++ b/third_party/openmax_dl/dl/sp/src/armSP_FFTInv_CCSToR_F32_preTwiddleRadix2_unsafe_s.S
@@ -0,0 +1,294 @@
+@//
+@//  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 is a modification of
+@//  armSP_FFTInv_CCSToR_S32_preTwiddleRadix2_unsafe_s.s to support float
+@//  instead of SC32.
+@//
+
+@//
+@// Description:
+@// Compute the "preTwiddleRadix2" stage prior to the call to the complexFFT
+@// It does a Z(k) = Feven(k) + jW^(-k) FOdd(k); k=0,1,2,...N/2-1 computation
+@//
+@//
+
+
+@// Include standard headers
+
+#include "dl/api/armCOMM_s.h"
+#include "dl/api/omxtypes_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            r1
+#define pFFTSpec        r2
+#define scale           r3
+
+
+@// Output registers
+#define result          r0
+
+@//Local Scratch Registers
+
+#define argTwiddle      r1
+#define argDst          r2
+#define argScale        r4
+#define tmpOrder        r4
+#define pTwiddle        r4
+#define pOut            r5
+#define subFFTSize      r7
+#define subFFTNum       r6
+#define N               r6
+#define order           r14
+#define diff            r9
+@// Total num of radix stages required to complete the FFT
+#define count           r8
+#define x0r             r4
+#define x0i             r5
+#define diffMinusOne    r2
+#define round           r3
+
+#define pOut1           r2
+#define size            r7
+#define step            r8
+#define step1           r9
+#define twStep          r10
+#define pTwiddleTmp     r11
+#define argTwiddle1     r12
+#define zero            r14
+
+@// Neon registers
+
+#define dX0     D0.F32
+#define dShift  D1.F32
+#define dX1     D1.F32
+#define dY0     D2.F32
+#define dY1     D3.F32
+#define dX0r    D0.F32
+#define dX0i    D1.F32
+#define dX1r    D2.F32
+#define dX1i    D3.F32
+#define dW0r    D4.F32
+#define dW0i    D5.F32
+#define dW1r    D6.F32
+#define dW1i    D7.F32
+#define dT0     D8.F32
+#define dT1     D9.F32
+#define dT2     D10.F32
+#define dT3     D11.F32
+#define qT0     D12.F32
+#define qT1     D14.F32
+#define qT2     D16.F32
+#define qT3     D18.F32
+#define dY0r    D4.F32
+#define dY0i    D5.F32
+#define dY1r    D6.F32
+#define dY1i    D7.F32
+
+#define dY2     D4.F32
+#define dY3     D5.F32
+#define dW0     D6.F32
+#define dW1     D7.F32
+#define dW0Tmp  D10.F32
+#define dW1Neg  D11.F32
+
+#define half    D13.F32
+
+@ Structure offsets for the FFTSpec
+        .set    ARMsFFTSpec_N, 0
+        .set    ARMsFFTSpec_pBitRev, 4
+        .set    ARMsFFTSpec_pTwiddle, 8
+        .set    ARMsFFTSpec_pBuf, 12
+
+        .MACRO FFTSTAGE scaled, inverse, name
+
+        @// Read the size from structure and take log
+        LDR     N, [pFFTSpec, #ARMsFFTSpec_N]
+
+        @// Read other structure parameters
+        LDR     pTwiddle, [pFFTSpec, #ARMsFFTSpec_pTwiddle]
+        LDR     pOut, [pFFTSpec, #ARMsFFTSpec_pBuf]
+
+        VMOV    half, 0.5
+
+
+        MOV     size,N,ASR #1                 @// preserve the contents of N
+        MOV     step,N,LSL #2                 @// step = N/2 * 8 bytes
+
+
+        @// Z(k) = 1/2 {[F(k) +  F'(N/2-k)] +j*W^(-k) [F(k) -  F'(N/2-k)]}
+        @// Note: W^(k) is stored as negated value and also need to
+        @// conjugate the values from the table
+
+        @// Z(0) : no need of twiddle multiply
+        @// Z(0) = 1/2 { [F(0) +  F'(N/2)] +j [F(0) -  F'(N/2)] }
+
+        VLD1    dX0,[pSrc],step
+        ADD     pOut1,pOut,step               @// pOut1 = pOut+ N/2*8 bytes
+
+        VLD1    dX1,[pSrc]!
+        @// twStep = 3N/8 * 8 bytes pointing to W^1
+        SUB     twStep,step,size,LSL #1
+
+        MOV     step1,size,LSL #2             @// step1 = N/4 * 8 = N/2*4 bytes
+        SUB     step1,step1,#8                @// (N/4-1)*8 bytes
+
+        VADD    dY0,dX0,dX1                   @// [b+d | a+c]
+        VSUB    dY1,dX0,dX1                   @// [b-d | a-c]
+        VMUL    dY0, dY0, half[0]
+        VMUL    dY1, dY1, half[0]
+
+        @// dY0= [a-c | a+c] ;dY1= [b-d | b+d]
+        VZIP    dY0,dY1
+
+        VSUB   dX0,dY0,dY1
+        SUBS   size,size,#2
+        VADD   dX1,dY0,dY1
+
+        SUB     pSrc,pSrc,step
+
+        VST1    dX0[0],[pOut1]!
+        ADD     pTwiddleTmp,pTwiddle,#8       @// W^2
+        VST1    dX1[1],[pOut1]!
+        ADD     argTwiddle1,pTwiddle,twStep   @// W^1
+
+
+        BLT     decrementScale\name
+        BEQ     lastElement\name
+
+
+        @// Z(k) = 1/2[F(k) +  F'(N/2-k)] +j*W^(-k) [F(k) -  F'(N/2-k)]
+        @// Note: W^k is stored as negative values in the table and also
+        @// need to conjugate the values from the table.
+        @//
+        @// Process 4 elements at a time. E.g: Z(1),Z(2) and Z(N/2-2),Z(N/2-1)
+        @// since both of them require F(1),F(2) and F(N/2-2),F(N/2-1)
+
+
+        SUB     step,step,#24
+evenOddButterflyLoop\name :
+
+
+        VLD1    dW0r,[argTwiddle1],step1
+        VLD1    dW1r,[argTwiddle1]!
+
+        VLD2    {dX0r,dX0i},[pSrc],step
+        SUB     argTwiddle1,argTwiddle1,step1
+        VLD2    {dX1r,dX1i},[pSrc]!
+
+        SUB     step1,step1,#8                @// (N/4-2)*8 bytes
+        VLD1    dW0i,[pTwiddleTmp],step1
+        VLD1    dW1i,[pTwiddleTmp]!
+        SUB     pSrc,pSrc,step
+
+        SUB     pTwiddleTmp,pTwiddleTmp,step1
+        VREV64  dX1r,dX1r
+        VREV64  dX1i,dX1i
+        SUBS    size,size,#4
+
+
+        VSUB    dT2,dX0r,dX1r                 @// a-c
+        VADD    dT3,dX0i,dX1i                 @// b+d
+        VADD    dT0,dX0r,dX1r                 @// a+c
+        VSUB    dT1,dX0i,dX1i                 @// b-d
+        SUB     step1,step1,#8
+
+        VMUL    dT2, dT2, half[0]
+        VMUL    dT3, dT3, half[0]
+
+        VMUL    dT0, dT0, half[0]
+        VMUL    dT1, dT1, half[0]
+
+        VZIP    dW1r,dW1i
+        VZIP    dW0r,dW0i
+
+
+        VMUL   dX1r,dW1r,dT2
+        VMUL   dX1i,dW1r,dT3
+        VMUL   dX0r,dW0r,dT2
+        VMUL   dX0i,dW0r,dT3
+
+        VMLS   dX1r,dW1i,dT3
+        VMLA   dX1i,dW1i,dT2
+
+        VMLA   dX0r,dW0i,dT3
+        VMLS   dX0i,dW0i,dT2
+
+
+        VADD    dY1r,dT0,dX1i                 @// F(N/2 -1)
+        VSUB    dY1i,dX1r,dT1
+
+        VREV64  dY1r,dY1r
+        VREV64  dY1i,dY1i
+
+
+        VADD    dY0r,dT0,dX0i                 @// F(1)
+        VSUB    dY0i,dT1,dX0r
+
+
+        VST2    {dY0r,dY0i},[pOut1],step
+        VST2    {dY1r,dY1i},[pOut1]!
+        SUB     pOut1,pOut1,step
+        SUB     step,step,#32                 @// (N/2-4)*8 bytes
+
+
+        BGT     evenOddButterflyLoop\name
+
+
+        @// set both the ptrs to the last element
+        SUB     pSrc,pSrc,#8
+        SUB     pOut1,pOut1,#8
+
+        @// Last element can be expanded as follows
+        @// 1/2[Z(k) + Z'(k)] - j w^-k [Z(k) - Z'(k)] (since W^k is stored as
+        @// -ve)
+        @// 1/2[(a+jb) + (a-jb)] - j w^-k [(a+jb) - (a-jb)]
+        @// 1/2[2a+j0] - j (c-jd) [0+j2b]
+        @// (a+bc, -bd)
+        @// Since (c,d) = (0,1) for the last element, result is just (a,-b)
+
+lastElement\name :
+        VLD1    dX0r,[pSrc]
+
+        VST1    dX0r[0],[pOut1]!
+        VNEG    dX0r,dX0r
+        VST1    dX0r[1],[pOut1]
+
+
+
+decrementScale\name :
+
+        .endm
+
+        M_START armSP_FFTInv_CCSToR_F32_preTwiddleRadix2_unsafe,r4
+
+            FFTSTAGE "FALSE","TRUE",Inv
+        M_END
+
+        .end