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@//
@// 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: omxSP_FFTFwd_CToC_SC32_Sfs_s.s
@// OpenMAX DL: v1.0.2
@// Last Modified Revision: 6684
@// Last Modified Date: Mon, 09 Jul 2007
@//
@// (c) Copyright 2007-2008 ARM Limited. All Rights Reserved.
@//
@//
@//
@// Description:
@// Compute an inverse FFT for a complex signal
@//
@// Include standard headers
#include "dl/api/armCOMM_s.h"
#include "dl/api/omxtypes_s.h"
@// Import symbols required from other files
@// (For example tables)
.extern armSP_FFTFwd_CToC_SC32_Sfs_Radix2_fs_OutOfPlace_unsafe
.extern armSP_FFTFwd_CToC_SC32_Radix2_fs_OutOfPlace_unsafe
.extern armSP_FFTFwd_CToC_SC32_Radix4_fs_OutOfPlace_unsafe
.extern armSP_FFTFwd_CToC_SC32_Radix8_fs_OutOfPlace_unsafe
.extern armSP_FFTFwd_CToC_SC32_Radix4_OutOfPlace_unsafe
.extern armSP_FFTFwd_CToC_SC32_Sfs_Radix4_fs_OutOfPlace_unsafe
.extern armSP_FFTFwd_CToC_SC32_Sfs_Radix8_fs_OutOfPlace_unsafe
.extern armSP_FFTFwd_CToC_SC32_Sfs_Radix4_OutOfPlace_unsafe
.extern armSP_FFTFwd_CToC_SC32_Sfs_Radix2_OutOfPlace_unsafe
.extern armSP_FFTFwd_CToC_SC32_Radix2_OutOfPlace_unsafe
@// Set debugging level
@//DEBUG_ON SETL {TRUE}
@// Guarding implementation by the processor name
@// Guarding implementation by the processor name
@// Import symbols required from other files
@// (For example tables)
.extern armSP_FFTFwd_CToC_SC32_Radix4_ls_OutOfPlace_unsafe
.extern armSP_FFTFwd_CToC_SC32_Radix2_ls_OutOfPlace_unsafe
.extern armSP_FFTFwd_CToC_SC32_Sfs_Radix4_ls_OutOfPlace_unsafe
.extern armSP_FFTFwd_CToC_SC32_Sfs_Radix2_ls_OutOfPlace_unsafe
@//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 comple the FFT
#define count r8
#define x0r r4
#define x0i r5
#define diffMinusOne r2
#define round r3
@// Neon registers
#define dX0 D0.S32
#define dShift D1.S32
@// Allocate stack memory required by the function
M_ALLOC4 diffOnStack, 4
@// Write function header
M_START omxSP_FFTFwd_CToC_SC32_Sfs,r11,d15
@ Structure offsets for the FFTSpec
.set ARMsFFTSpec_N, 0
.set ARMsFFTSpec_pBitRev, 4
.set ARMsFFTSpec_pTwiddle, 8
.set ARMsFFTSpec_pBuf, 12
@// Define stack arguments
@// 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]
CLZ order,N @// N = 2^order
RSB order,order,#31
MOV subFFTSize,#1
@//MOV subFFTNum,N
CMP order,#3
BGT orderGreaterthan3 @// order > 3
CMP order,#1
BGE orderGreaterthan0 @// order > 0
M_STR scale, diffOnStack,LT @// order = 0
VLD1 dX0,[pSrc]
VST1 dX0,[pDst]
MOV pSrc,pDst
BLT FFTEnd
orderGreaterthan0:
@// set the buffers appropriately for various orders
CMP order,#2
MOVNE argDst,pDst
MOVEQ argDst,pOut
MOVEQ pOut,pDst @// Pass the first stage destination in RN5
MOV argTwiddle,pTwiddle
SUBS diff,scale,order
M_STR diff,diffOnStack
MOVGT scale,order
@// Now scale <= order
CMP order,#1
BGT orderGreaterthan1
SUBS scale,scale,#1
BLEQ armSP_FFTFwd_CToC_SC32_Sfs_Radix2_fs_OutOfPlace_unsafe @// order = 1
BLLT armSP_FFTFwd_CToC_SC32_Radix2_fs_OutOfPlace_unsafe @// order = 1
B FFTEnd
orderGreaterthan1:
CMP order,#2
MOV argScale,scale
BGT orderGreaterthan2
SUBS argScale,argScale,#1
BLGE armSP_FFTFwd_CToC_SC32_Sfs_Radix2_fs_OutOfPlace_unsafe @// order =2
BLLT armSP_FFTFwd_CToC_SC32_Radix2_fs_OutOfPlace_unsafe
SUBS argScale,argScale,#1
BLEQ armSP_FFTFwd_CToC_SC32_Sfs_Radix2_ls_OutOfPlace_unsafe
BLLT armSP_FFTFwd_CToC_SC32_Radix2_ls_OutOfPlace_unsafe
B FFTEnd
orderGreaterthan2: @// order =3
SUBS argScale,argScale,#1
BLGE armSP_FFTFwd_CToC_SC32_Sfs_Radix2_fs_OutOfPlace_unsafe // "fs" means first stage
BLLT armSP_FFTFwd_CToC_SC32_Radix2_fs_OutOfPlace_unsafe
SUBS argScale,argScale,#1
BLGE armSP_FFTFwd_CToC_SC32_Sfs_Radix2_OutOfPlace_unsafe
BLLT armSP_FFTFwd_CToC_SC32_Radix2_OutOfPlace_unsafe
SUBS argScale,argScale,#1
BLEQ armSP_FFTFwd_CToC_SC32_Sfs_Radix2_ls_OutOfPlace_unsafe // "ls" means last stage
BLLT armSP_FFTFwd_CToC_SC32_Radix2_ls_OutOfPlace_unsafe
B FFTEnd
orderGreaterthan3:
@// check scale = 0 or scale = order
SUBS diff, scale, order @// scale > order
MOVGT scale,order
BGE specialScaleCase @// scale = 0 or scale = order
CMP scale,#0
BEQ specialScaleCase
B generalScaleCase
specialScaleCase: @// scale = 0 or scale = order and order >= 2
TST order, #2 @// Set input args to fft stages
MOVNE argDst,pDst
MOVEQ argDst,pOut
MOVEQ pOut,pDst @// Pass the first stage destination in RN5
MOV argTwiddle,pTwiddle
CMP diff,#0
M_STR diff, diffOnStack
BGE scaleEqualsOrder
@//check for even or odd order
@// NOTE: The following combination of BL's would work fine eventhough the first
@// BL would corrupt the flags. This is because the end of the "grpZeroSetLoop" loop inside
@// armSP_FFTFwd_CToC_SC32_Radix4_fs_OutOfPlace_unsafe sets the Z flag to EQ
TST order,#0x00000001
BLEQ armSP_FFTFwd_CToC_SC32_Radix4_fs_OutOfPlace_unsafe
BLNE armSP_FFTFwd_CToC_SC32_Radix8_fs_OutOfPlace_unsafe
CMP subFFTNum,#4
BLT FFTEnd
unscaledRadix4Loop:
BEQ lastStageUnscaledRadix4
BL armSP_FFTFwd_CToC_SC32_Radix4_OutOfPlace_unsafe
CMP subFFTNum,#4
B unscaledRadix4Loop
lastStageUnscaledRadix4:
BL armSP_FFTFwd_CToC_SC32_Radix4_ls_OutOfPlace_unsafe
B FFTEnd
scaleEqualsOrder:
@//check for even or odd order
@// NOTE: The following combination of BL's would work fine eventhough the first
@// BL would corrupt the flags. This is because the end of the "grpZeroSetLoop" loop inside
@// armSP_FFTFwd_CToC_SC32_Radix4_fs_OutOfPlace_unsafe sets the Z flag to EQ
TST order,#0x00000001
BLEQ armSP_FFTFwd_CToC_SC32_Sfs_Radix4_fs_OutOfPlace_unsafe
BLNE armSP_FFTFwd_CToC_SC32_Sfs_Radix8_fs_OutOfPlace_unsafe
CMP subFFTNum,#4
BLT FFTEnd
scaledRadix4Loop:
BEQ lastStageScaledRadix4
BL armSP_FFTFwd_CToC_SC32_Sfs_Radix4_OutOfPlace_unsafe
CMP subFFTNum,#4
B scaledRadix4Loop
lastStageScaledRadix4:
BL armSP_FFTFwd_CToC_SC32_Sfs_Radix4_ls_OutOfPlace_unsafe
B FFTEnd
generalScaleCase: @// 0 < scale < order and order >= 2
@// Determine the correct destination buffer
SUB diff,order,scale
TST diff,#0x01
ADDEQ count,scale,diff,LSR #1 @// count = scale + (order - scale)/2
MOVNE count,order
TST count,#0x01 @// Is count even or odd ?
MOVNE argDst,pDst @// Set input args to fft stages
MOVEQ argDst,pOut
MOVEQ pOut,pDst @// Pass the first stage destination in RN5
MOV argTwiddle,pTwiddle
M_STR diff, diffOnStack
MOV argScale,scale @// Put scale in RN4 so as to save and restore
BL armSP_FFTFwd_CToC_SC32_Sfs_Radix2_fs_OutOfPlace_unsafe @// scaled first stage
SUBS argScale,argScale,#1
scaledRadix2Loop:
BLGT armSP_FFTFwd_CToC_SC32_Sfs_Radix2_OutOfPlace_unsafe
SUBS argScale,argScale,#1 @// save and restore scale (RN4) in the scaled stages
BGT scaledRadix2Loop
M_LDR diff, diffOnStack
@//check for even or odd order
TST diff,#0x00000001
BEQ generalUnscaledRadix4Loop
B unscaledRadix2Loop
generalUnscaledRadix4Loop:
CMP subFFTNum,#4
BEQ generalLastStageUnscaledRadix4
BL armSP_FFTFwd_CToC_SC32_Radix4_OutOfPlace_unsafe
B generalUnscaledRadix4Loop
generalLastStageUnscaledRadix4:
BL armSP_FFTFwd_CToC_SC32_Radix4_ls_OutOfPlace_unsafe
B End
unscaledRadix2Loop:
CMP subFFTNum,#2
BEQ generalLastStageUnscaledRadix2
BL armSP_FFTFwd_CToC_SC32_Radix2_OutOfPlace_unsafe
B unscaledRadix2Loop
generalLastStageUnscaledRadix2:
BL armSP_FFTFwd_CToC_SC32_Radix2_ls_OutOfPlace_unsafe
B End
FFTEnd: @// Does only the scaling
M_LDR diff, diffOnStack
CMP diff,#0
BLE End
RSB diff,diff,#0 @// to use VRSHL for right shift by a variable
VDUP dShift,diff
scaleFFTData: @// N = subFFTSize ; dataptr = pDst ; scale = diff
VLD1 {dX0},[pSrc] @// pSrc contains pDst pointer
SUBS subFFTSize,subFFTSize,#1
VRSHL dX0,dShift
VST1 {dX0},[pSrc]!
BGT scaleFFTData
End:
@// Set return value
MOV result, #OMX_Sts_NoErr
@// Write function tail
M_END
.end
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