From d8782ce5fd08a2fb7b10ba9eff40079907511402 Mon Sep 17 00:00:00 2001 From: Max Kellermann Date: Fri, 22 Aug 2014 06:58:08 +0200 Subject: decoder/dsf: simplify dsf_to_pcm_order() Don't pass the buffer size to the function, as it's known at compile time. Use "restrict" on the pointer arguments, and merge the two loops, which allows the compiler to optimize this loop with a few SSE2 instructions. --- src/decoder/plugins/DsfDecoderPlugin.cxx | 15 +++++---------- 1 file changed, 5 insertions(+), 10 deletions(-) (limited to 'src/decoder/plugins/DsfDecoderPlugin.cxx') diff --git a/src/decoder/plugins/DsfDecoderPlugin.cxx b/src/decoder/plugins/DsfDecoderPlugin.cxx index 98538a842..8c6c3a03d 100644 --- a/src/decoder/plugins/DsfDecoderPlugin.cxx +++ b/src/decoder/plugins/DsfDecoderPlugin.cxx @@ -195,16 +195,11 @@ bit_reverse_buffer(uint8_t *p, uint8_t *end) * order. */ static void -dsf_to_pcm_order(uint8_t *dest, const uint8_t *src, size_t nrbytes) +dsf_to_pcm_order(uint8_t *gcc_restrict dest, const uint8_t *gcc_restrict src) { - for (size_t i = 0, j = 0; i < nrbytes; i += 2) { - dest[i] = src[j]; - j++; - } - - for (size_t i = 1, j = 0; i < nrbytes; i += 2) { - dest[i] = src[DSF_BLOCK_SIZE + j]; - j++; + for (size_t i = 0; i < DSF_BLOCK_SIZE; ++i) { + dest[2 * i] = src[i]; + dest[2 * i + 1] = src[DSF_BLOCK_SIZE + i]; } } @@ -236,7 +231,7 @@ dsf_decode_chunk(Decoder &decoder, InputStream &is, bit_reverse_buffer(buffer, buffer + block_size); uint8_t interleaved_buffer[DSF_BLOCK_SIZE * 2]; - dsf_to_pcm_order(interleaved_buffer, buffer, block_size); + dsf_to_pcm_order(interleaved_buffer, buffer); const auto cmd = decoder_data(decoder, is, interleaved_buffer, block_size, -- cgit v1.2.3