From 0a6c0e26b73d0cbf4b324b38e1be484d6a6c27e8 Mon Sep 17 00:00:00 2001 From: Andre Noll Date: Tue, 2 Apr 2013 17:10:08 +0000 Subject: [PATCH] compress: Further optimize inner loop. This kills the local adjusted_sample variable of the inner loop of compress_post_select(). Surprisingly enough, this saves another 5% of execution time. --- compress_filter.c | 22 +++++++++++++--------- 1 file changed, 13 insertions(+), 9 deletions(-) diff --git a/compress_filter.c b/compress_filter.c index b01c01a4..499a9e76 100644 --- a/compress_filter.c +++ b/compress_filter.c @@ -75,19 +75,23 @@ next_buffer: op = para_malloc(length); for (i = 0; i < length / 2; i++) { /* be careful in that heat, my dear */ - int sample = *ip++, adjusted_sample; + int sample = *ip++; + bool neg = false; - adjusted_sample = sample > 0? sample : -sample; - adjusted_sample *= pcd->current_gain; - adjusted_sample >>= gain_shift; - if (adjusted_sample > 32767) { /* clip */ - adjusted_sample = 32767; + if (sample < 0) { + sample = -sample; + neg = true; + } + sample *= pcd->current_gain; + sample >>= gain_shift; + if (sample > 32767) { /* clip */ + sample = 32767; pcd->current_gain = (3 * pcd->current_gain + (1 << pcd->conf->inertia_arg)) / 4; pcd->peak = 0; - } else if (adjusted_sample > pcd->peak) - pcd->peak = adjusted_sample; - op[i] = sample >= 0? adjusted_sample : -adjusted_sample; + } else if (sample > pcd->peak) + pcd->peak = sample; + op[i] = neg? -sample : sample; if (++pcd->num_samples & mask) continue; // PARA_DEBUG_LOG("gain: %u, peak: %u\n", pcd->current_gain, -- 2.39.2