From 3114df7fe912f207f291ca490ce55b791bac0dfe Mon Sep 17 00:00:00 2001 From: TT Date: Sun, 17 Nov 2019 11:16:36 +0900 Subject: [PATCH] fix #92 : 'for' loop initial declarations --- fft.h | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/fft.h b/fft.h index 9f8c44c..0c367b7 100644 --- a/fft.h +++ b/fft.h @@ -28,7 +28,8 @@ static uint16_t reverse_bits(uint16_t x, int n) { uint16_t result = 0; - for (int i = 0; i < n; i++, x >>= 1) + int i; + for (i = 0; i < n; i++, x >>= 1) result = (result << 1) | (x & 1U); return result; } @@ -43,8 +44,10 @@ static void fft256(float array[][2], const uint8_t dir) { const uint8_t real = dir & 1; const uint8_t imag = ~real & 1; + uint16_t i; + uint16_t size; - for (uint16_t i = 0; i < n; i++) { + for (i = 0; i < n; i++) { uint16_t j = reverse_bits(i, levels); if (j > i) { float temp = array[i][real]; @@ -57,11 +60,13 @@ static void fft256(float array[][2], const uint8_t dir) { } // Cooley-Tukey decimation-in-time radix-2 FFT - for (uint16_t size = 2; size <= n; size *= 2) { + for (size = 2; size <= n; size *= 2) { uint16_t halfsize = size / 2; uint16_t tablestep = n / size; - for (uint16_t i = 0; i < n; i += size) { - for (uint16_t j = i, k = 0; j < i + halfsize; j++, k += tablestep) { + uint16_t i; + for (i = 0; i < n; i += size) { + uint16_t j, k; + for (j = i, k = 0; j < i + halfsize; j++, k += tablestep) { uint16_t l = j + halfsize; float tpre = array[l][real] * cos(2 * M_PI * k / 256) + array[l][imag] * sin(2 * M_PI * k / 256); float tpim = -array[l][real] * sin(2 * M_PI * k / 256) + array[l][imag] * cos(2 * M_PI * k / 256);