Diff: cmsis_dsp/TransformFunctions/arm_bitreversal2.S

Revision:

3:7a284390b0ce

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/cmsis_dsp/TransformFunctions/arm_bitreversal2.S	Fri Nov 08 13:45:10 2013 +0000
@@ -0,0 +1,148 @@
+;/* ----------------------------------------------------------------------    
+;* Copyright (C) 2010-2013 ARM Limited. All rights reserved.    
+;*    
+;* $Date:        17. January 2013  
+;* $Revision: 	V1.4.1  
+;*    
+;* Project: 	    CMSIS DSP Library    
+;* Title:	    arm_bitreversal2.S   
+;*    
+;* Description:	This is the arm_bitreversal_32 function done in
+;*                assembly for maximum speed.  This function is called
+;*                after doing an fft to reorder the output.  The function
+;*                is loop unrolled by 2.
+;*    
+;* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
+;*  
+;* Redistribution and use in source and binary forms, with or without 
+;* modification, are permitted provided that the following conditions
+;* are met:
+;*   - Redistributions of source code must retain the above copyright
+;*     notice, this list of conditions and the following disclaimer.
+;*   - Redistributions in binary form must reproduce the above copyright
+;*     notice, this list of conditions and the following disclaimer in
+;*     the documentation and/or other materials provided with the 
+;*     distribution.
+;*   - Neither the name of ARM LIMITED nor the names of its contributors
+;*     may be used to endorse or promote products derived from this
+;*     software without specific prior written permission.
+;*
+;* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+;* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+;* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+;* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 
+;* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+;* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+;* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+;* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+;* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+;* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+;* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+;* POSSIBILITY OF SUCH DAMAGE.   
+;* -------------------------------------------------------------------- */
+#if defined(__CC_ARM) //Keil
+	#define CODESECT AREA     ||.text||, CODE, READONLY, ALIGN=2
+	#define LABEL
+#elif defined(__IASMARM__) //IAR
+	#define CODESECT SECTION `.text`:CODE
+	#define PROC 
+	#define LABEL 
+	#define ENDP
+	#define EXPORT PUBLIC
+#elif defined (__GNUC__) //GCC
+	.syntax unified
+	.cpu cortex-m4
+	.fpu softvfp
+	#define THUMB .thumb
+	#define CODESECT .section text
+	#define EXPORT .global
+	#define PROC :
+	#define LABEL :
+	#define ENDP
+	#define END
+#endif
+
+	CODESECT
+	THUMB
+
+;/*    
+;* @brief  In-place bit reversal function.   
+;* @param[in, out] *pSrc        points to the in-place buffer of unknown 32-bit data type. 
+;* @param[in]      bitRevLen    bit reversal table length
+;* @param[in]      *pBitRevTab  points to bit reversal table.   
+;* @return none.   
+;*/
+	EXPORT arm_bitreversal_32
+   
+#if defined(ARM_MATH_CM0) || defined(ARM_MATH_CM0PLUS)
+
+arm_bitreversal_32 PROC
+	ADDS     r3,r1,#1
+	PUSH     {r4-r6}           
+	ADDS     r1,r2,#0          
+	LSRS     r3,r3,#1          
+arm_bitreversal_32_0 LABEL
+	LDRH     r2,[r1,#2]        
+	LDRH     r6,[r1,#0]    
+	ADD      r2,r0,r2   
+	ADD      r6,r0,r6   
+	LDR      r5,[r2,#0] 
+	LDR      r4,[r6,#0]
+	STR      r5,[r6,#0]
+	STR      r4,[r2,#0]    
+	LDR      r5,[r2,#4]        
+	LDR      r4,[r6,#4]       
+	STR      r5,[r6,#4]       
+	STR      r4,[r2,#4]        
+	ADDS     r1,r1,#4          
+	SUBS     r3,r3,#1          
+	BNE      arm_bitreversal_32_0
+	POP      {r4-r6}
+	BX       lr
+	ENDP
+
+#else
+
+arm_bitreversal_32 PROC
+	ADDS     r3,r1,#1
+	CMP      r3,#1
+	IT       LS
+	BXLS     lr
+	PUSH     {r4-r9}           
+	ADDS     r1,r2,#2          
+	LSRS     r3,r3,#2          
+arm_bitreversal_32_0 LABEL       ;/* loop unrolled by 2 */
+	LDRH     r8,[r1,#4]        
+	LDRH     r9,[r1,#2]  
+	LDRH     r2,[r1,#0]        
+	LDRH     r12,[r1,#-2]    
+	ADD      r8,r0,r8   
+	ADD      r9,r0,r9    
+	ADD      r2,r0,r2   
+	ADD      r12,r0,r12   
+	LDR      r7,[r9,#0] 
+	LDR      r6,[r8,#0]
+	LDR      r5,[r2,#0] 
+	LDR      r4,[r12,#0]
+	STR      r6,[r9,#0]
+	STR      r7,[r8,#0] 
+	STR      r5,[r12,#0]
+	STR      r4,[r2,#0]      
+	LDR      r7,[r9,#4]        
+	LDR      r6,[r8,#4] 
+	LDR      r5,[r2,#4]        
+	LDR      r4,[r12,#4]           
+	STR      r6,[r9,#4]       
+	STR      r7,[r8,#4]   
+	STR      r5,[r12,#4]       
+	STR      r4,[r2,#4]        
+	ADDS     r1,r1,#8          
+	SUBS     r3,r3,#1          
+	BNE      arm_bitreversal_32_0
+	POP      {r4-r9}
+	BX       lr
+	ENDP
+   
+#endif
+   
+	END