Split rfft_fast_init_f32 into separate initializer functions.

The rationale here is that if the caller knows the size FFT they require at compile time, only the look-up tables required for that size are placed in the data segment (ROM). This saves between ~40k to ~80k of ROM when only using a single FFT size.
8 years ago · 0f5b33ee1b
parent da38c27dd0
commit 0f5b33ee1b
2 changed files with 210 additions and 0 deletions
--- a/Include/arm_math.h
+++ b/Include/arm_math.h
@ -2224,6 +2224,23 @@ arm_status arm_rfft_fast_init_f32 (
   arm_rfft_fast_instance_f32 * S,
   uint16_t fftLen);

+arm_status arm_rfft_32_fast_init_f32 ( arm_rfft_fast_instance_f32 * S );
+
+arm_status arm_rfft_64_fast_init_f32 ( arm_rfft_fast_instance_f32 * S );
+
+arm_status arm_rfft_128_fast_init_f32 ( arm_rfft_fast_instance_f32 * S );
+
+arm_status arm_rfft_256_fast_init_f32 ( arm_rfft_fast_instance_f32 * S );
+
+arm_status arm_rfft_512_fast_init_f32 ( arm_rfft_fast_instance_f32 * S );
+
+arm_status arm_rfft_1024_fast_init_f32 ( arm_rfft_fast_instance_f32 * S );
+
+arm_status arm_rfft_2048_fast_init_f32 ( arm_rfft_fast_instance_f32 * S );
+
+arm_status arm_rfft_4096_fast_init_f32 ( arm_rfft_fast_instance_f32 * S );
+
+
 void arm_rfft_fast_f32(
  arm_rfft_fast_instance_f32 * S,
  float32_t * p, float32_t * pOut,
--- a/Source/TransformFunctions/arm_rfft_fast_init_f32.c
+++ b/Source/TransformFunctions/arm_rfft_fast_init_f32.c
@ -38,6 +38,199 @@
 * @{
 */

+
+/**
+* @brief  Initialization function for the 32pt floating-point real FFT.
+* @param[in,out] *S             points to an arm_rfft_fast_instance_f32 structure.
+* @return        The function returns ARM_MATH_SUCCESS if initialization is successful or ARM_MATH_ARGUMENT_ERROR if an error is detected.
+*/
+arm_status arm_rfft_32_fast_init_f32( arm_rfft_fast_instance_f32 * S ) {
+
+  arm_cfft_instance_f32 * Sint;
+
+  if( !S ) return ARM_MATH_ARGUMENT_ERROR;
+
+  Sint = &(S->Sint);
+  Sint->fftLen = 16U;
+  S->fftLenRFFT = 32U;
+
+  Sint->bitRevLength = ARMBITREVINDEXTABLE_16_TABLE_LENGTH;
+  Sint->pBitRevTable = (uint16_t *)armBitRevIndexTable16;
+  Sint->pTwiddle     = (float32_t *) twiddleCoef_16;
+  S->pTwiddleRFFT    = (float32_t *) twiddleCoef_rfft_32;
+
+  return ARM_MATH_SUCCESS;
+
+}
+
+/**
+* @brief  Initialization function for the 64pt floating-point real FFT.
+* @param[in,out] *S             points to an arm_rfft_fast_instance_f32 structure.
+* @return        The function returns ARM_MATH_SUCCESS if initialization is successful or ARM_MATH_ARGUMENT_ERROR if an error is detected.
+*/
+arm_status arm_rfft_64_fast_init_f32( arm_rfft_fast_instance_f32 * S ) {
+
+  arm_cfft_instance_f32 * Sint;
+
+  if( !S ) return ARM_MATH_ARGUMENT_ERROR;
+
+  Sint = &(S->Sint);
+  Sint->fftLen = 32U;
+  S->fftLenRFFT = 64U;
+
+  Sint->bitRevLength = ARMBITREVINDEXTABLE_32_TABLE_LENGTH;
+  Sint->pBitRevTable = (uint16_t *)armBitRevIndexTable32;
+  Sint->pTwiddle     = (float32_t *) twiddleCoef_32;
+  S->pTwiddleRFFT    = (float32_t *) twiddleCoef_rfft_64;
+
+  return ARM_MATH_SUCCESS;
+
+}
+
+/**
+* @brief  Initialization function for the 128pt floating-point real FFT.
+* @param[in,out] *S             points to an arm_rfft_fast_instance_f32 structure.
+* @return        The function returns ARM_MATH_SUCCESS if initialization is successful or ARM_MATH_ARGUMENT_ERROR if an error is detected.
+*/
+arm_status arm_rfft_128_fast_init_f32( arm_rfft_fast_instance_f32 * S ) {
+
+  arm_cfft_instance_f32 * Sint;
+
+  if( !S ) return ARM_MATH_ARGUMENT_ERROR;
+
+  Sint = &(S->Sint);
+  Sint->fftLen = 64U;
+  S->fftLenRFFT = 128U;
+
+  Sint->bitRevLength = ARMBITREVINDEXTABLE_64_TABLE_LENGTH;
+  Sint->pBitRevTable = (uint16_t *)armBitRevIndexTable64;
+  Sint->pTwiddle     = (float32_t *) twiddleCoef_64;
+  S->pTwiddleRFFT    = (float32_t *) twiddleCoef_rfft_128;
+
+  return ARM_MATH_SUCCESS;
+
+}
+
+/**
+* @brief  Initialization function for the 256pt floating-point real FFT.
+* @param[in,out] *S             points to an arm_rfft_fast_instance_f32 structure.
+* @return        The function returns ARM_MATH_SUCCESS if initialization is successful or ARM_MATH_ARGUMENT_ERROR if an error is detected.
+*/
+arm_status arm_rfft_256_fast_init_f32( arm_rfft_fast_instance_f32 * S ) {
+
+  arm_cfft_instance_f32 * Sint;
+
+  if( !S ) return ARM_MATH_ARGUMENT_ERROR;
+
+  Sint = &(S->Sint);
+  Sint->fftLen = 128U;
+  S->fftLenRFFT = 256U;
+
+  Sint->bitRevLength = ARMBITREVINDEXTABLE_128_TABLE_LENGTH;
+  Sint->pBitRevTable = (uint16_t *)armBitRevIndexTable128;
+  Sint->pTwiddle     = (float32_t *) twiddleCoef_128;
+  S->pTwiddleRFFT    = (float32_t *) twiddleCoef_rfft_256;
+
+  return ARM_MATH_SUCCESS;
+
+}
+
+/**
+* @brief  Initialization function for the 512pt floating-point real FFT.
+* @param[in,out] *S             points to an arm_rfft_fast_instance_f32 structure.
+* @return        The function returns ARM_MATH_SUCCESS if initialization is successful or ARM_MATH_ARGUMENT_ERROR if an error is detected.
+*/
+arm_status arm_rfft_512_fast_init_f32( arm_rfft_fast_instance_f32 * S ) {
+
+  arm_cfft_instance_f32 * Sint;
+
+  if( !S ) return ARM_MATH_ARGUMENT_ERROR;
+
+  Sint = &(S->Sint);
+  Sint->fftLen = 256U;
+  S->fftLenRFFT = 512U;
+
+  Sint->bitRevLength = ARMBITREVINDEXTABLE_256_TABLE_LENGTH;
+  Sint->pBitRevTable = (uint16_t *)armBitRevIndexTable256;
+  Sint->pTwiddle     = (float32_t *) twiddleCoef_256;
+  S->pTwiddleRFFT    = (float32_t *) twiddleCoef_rfft_512;
+
+  return ARM_MATH_SUCCESS;
+
+}
+
+/**
+* @brief  Initialization function for the 1024pt floating-point real FFT.
+* @param[in,out] *S             points to an arm_rfft_fast_instance_f32 structure.
+* @return        The function returns ARM_MATH_SUCCESS if initialization is successful or ARM_MATH_ARGUMENT_ERROR if an error is detected.
+*/
+arm_status arm_rfft_1024_fast_init_f32( arm_rfft_fast_instance_f32 * S ) {
+
+  arm_cfft_instance_f32 * Sint;
+
+  if( !S ) return ARM_MATH_ARGUMENT_ERROR;
+
+  Sint = &(S->Sint);
+  Sint->fftLen = 512U;
+  S->fftLenRFFT = 1024U;
+
+  Sint->bitRevLength = ARMBITREVINDEXTABLE_512_TABLE_LENGTH;
+  Sint->pBitRevTable = (uint16_t *)armBitRevIndexTable512;
+  Sint->pTwiddle     = (float32_t *) twiddleCoef_512;
+  S->pTwiddleRFFT    = (float32_t *) twiddleCoef_rfft_1024;
+
+  return ARM_MATH_SUCCESS;
+
+}
+
+/**
+* @brief  Initialization function for the 2048pt floating-point real FFT.
+* @param[in,out] *S             points to an arm_rfft_fast_instance_f32 structure.
+* @return        The function returns ARM_MATH_SUCCESS if initialization is successful or ARM_MATH_ARGUMENT_ERROR if an error is detected.
+*/
+arm_status arm_rfft_2048_fast_init_f32( arm_rfft_fast_instance_f32 * S ) {
+
+  arm_cfft_instance_f32 * Sint;
+
+  if( !S ) return ARM_MATH_ARGUMENT_ERROR;
+
+  Sint = &(S->Sint);
+  Sint->fftLen = 1024U;
+  S->fftLenRFFT = 2048U;
+
+  Sint->bitRevLength = ARMBITREVINDEXTABLE_1024_TABLE_LENGTH;
+  Sint->pBitRevTable = (uint16_t *)armBitRevIndexTable1024;
+  Sint->pTwiddle     = (float32_t *) twiddleCoef_1024;
+  S->pTwiddleRFFT    = (float32_t *) twiddleCoef_rfft_2048;
+
+  return ARM_MATH_SUCCESS;
+
+}
+
+/**
+* @brief  Initialization function for the 4096pt floating-point real FFT.
+* @param[in,out] *S             points to an arm_rfft_fast_instance_f32 structure.
+* @return        The function returns ARM_MATH_SUCCESS if initialization is successful or ARM_MATH_ARGUMENT_ERROR if an error is detected.
+*/
+arm_status arm_rfft_4096_fast_init_f32( arm_rfft_fast_instance_f32 * S ) {
+
+  arm_cfft_instance_f32 * Sint;
+
+  if( !S ) return ARM_MATH_ARGUMENT_ERROR;
+
+  Sint = &(S->Sint);
+  Sint->fftLen = 2048U;
+  S->fftLenRFFT = 4096U;
+
+  Sint->bitRevLength = ARMBITREVINDEXTABLE_2048_TABLE_LENGTH;
+  Sint->pBitRevTable = (uint16_t *)armBitRevIndexTable2048;
+  Sint->pTwiddle     = (float32_t *) twiddleCoef_2048;
+  S->pTwiddleRFFT    = (float32_t *) twiddleCoef_rfft_4096;
+
+  return ARM_MATH_SUCCESS;
+
+}
+
 /**
 * @brief  Initialization function for the floating-point real FFT.
 * @param[in,out] *S             points to an arm_rfft_fast_instance_f32 structure.