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+/*************************** Fraunhofer IIS FDK Tools **********************
+
+ (C) Copyright Fraunhofer IIS (2005)
+ All Rights Reserved
+
+ Please be advised that this software and/or program delivery is
+ Confidential Information of Fraunhofer and subject to and covered by the
+
+ Fraunhofer IIS Software Evaluation Agreement
+ between Google Inc. and Fraunhofer
+ effective and in full force since March 1, 2012.
+
+ You may use this software and/or program only under the terms and
+ conditions described in the above mentioned Fraunhofer IIS Software
+ Evaluation Agreement. Any other and/or further use requires a separate agreement.
+
+
+ $Id$
+ Author(s):
+ Description: bitreversal of input data
+
+ This software and/or program is protected by copyright law and international
+ treaties. Any reproduction or distribution of this software and/or program,
+ or any portion of it, may result in severe civil and criminal penalties, and
+ will be prosecuted to the maximum extent possible under law.
+
+******************************************************************************/
+
+
+
+#if defined(FUNCTION_scramble)
+#if defined(__GNUC__) /* cppp replaced: elif */
+
+#define FUNCTION_scramble
+
+#if defined(__ARM_ARCH_5TE__)
+#define USE_LDRD_STRD /* LDRD requires 8 byte data alignment. */
+#endif
+
+inline void scramble(FIXP_DBL x [], INT n) {
+ FDK_ASSERT(!(((INT)x)&(ALIGNMENT_DEFAULT-1)));
+ asm("mov r2, #1;\n" /* r2(m) = 1; */
+ "sub r3, %1, #1;\n" /* r3 = n-1; */
+ "mov r4, #0;\n" /* r4(j) = 0; */
+
+"scramble_m_loop%=:\n" /* { */
+ "mov r5, %1;\n" /* r5(k) = 1; */
+
+"scramble_k_loop%=:\n" /* { */
+ "mov r5, r5, lsr #1;\n" /* k >>= 1; */
+ "eor r4, r4, r5;\n" /* j ^=k; */
+ "ands r10, r4, r5;\n" /* r10 = r4 & r5; */
+ "beq scramble_k_loop%=;\n" /* } while (r10 == 0); */
+
+ "cmp r4, r2;\n" /* if (r4 < r2) break; */
+ "bcc scramble_m_loop_end%=;\n"
+
+#ifdef USE_LDRD_STRD
+ "mov r5, r2, lsl #3;\n" /* m(r5) = r2*4*2 */
+ "ldrd r10, [%0, r5];\n" /* r10 = x[r5], x7 = x[r5+1] */
+ "mov r6, r4, lsl #3;\n" /* j(r6) = r4*4*2 */
+ "ldrd r8, [%0, r6];\n" /* r8 = x[r6], r9 = x[r6+1]; */
+ "strd r10, [%0, r6];\n" /* x[r6,r6+1] = r10,r11; */
+ "strd r8, [%0, r5];\n" /* x[r5,r5+1] = r8,r9; */
+#else
+ "mov r5, r2, lsl #3;\n" /* m(r5) = r2*4*2 */
+ "ldr r10, [%0, r5];\n"
+ "mov r6, r4, lsl #3;\n" /* j(r6) = r4*4*2 */
+ "ldr r11, [%0, r6];\n"
+
+ "str r10, [%0, r6];\n"
+ "str r11, [%0, r5];\n"
+
+ "add r5, r5, #4;"
+ "ldr r10, [%0, r5];\n"
+ "add r6, r6, #4;"
+ "ldr r11, [%0, r6];\n"
+ "str r10, [%0, r6];\n"
+ "str r11, [%0, r5];\n"
+#endif
+"scramble_m_loop_end%=:\n"
+ "add r2, r2, #1;\n" /* r2++; */
+ "cmp r2, r3;\n"
+ "bcc scramble_m_loop%=;\n" /* } while (r2(m) < r3(n-1)); */
+ :
+ : "r"(x), "r"(n)
+#ifdef USE_LDRD_STRD
+ : "r2","r3", "r4","r5", "r10","r11", "r8","r9", "r6" );
+#else
+ : "r2","r3", "r4","r5", "r10","r11", "r6" );
+#endif
+}
+#else
+/* Force C implementation if no assembler version available. */
+#undef FUNCTION_scramble
+#endif /* Toolchain selection. */
+
+#endif /* defined(FUNCTION_scramble) */