From c2b2fc1640b380b5bb17960975ae6b21c3f8de2d Mon Sep 17 00:00:00 2001 From: Siarhei Siamashka Date: Mon, 14 Mar 2011 15:16:30 -0300 Subject: sbc: new 'sbc_calc_scalefactors_j' function added to sbc primitives The code for scale factors calculation with joint stereo support has been moved to a separate function. It can get platform-specific SIMD optimizations later for best possible performance. But even this change in C code improves performance because of the use of __builtin_clz() instead of loops similar to what was done to sbc_calc_scalefactors earlier. Also technically it does loop unrolling by processing two channels at once, which might be either good or bad for performance (if the registers pressure is increased and more data is spilled to memory). But the benchmark from 32-bit x86 system (pentium-m) shows that it got clearly faster: $ time ./sbcenc.old -b53 -s8 -j test.au > /dev/null real 0m1.868s user 0m1.808s sys 0m0.048s $ time ./sbcenc.new -b53 -s8 -j test.au > /dev/null real 0m1.742s user 0m1.668s sys 0m0.064s --- src/modules/bluetooth/sbc/sbc_primitives.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'src/modules/bluetooth/sbc/sbc_primitives.h') diff --git a/src/modules/bluetooth/sbc/sbc_primitives.h b/src/modules/bluetooth/sbc/sbc_primitives.h index 3d01c115..b4b9df2f 100644 --- a/src/modules/bluetooth/sbc/sbc_primitives.h +++ b/src/modules/bluetooth/sbc/sbc_primitives.h @@ -62,6 +62,10 @@ struct sbc_encoder_state { void (*sbc_calc_scalefactors)(int32_t sb_sample_f[16][2][8], uint32_t scale_factor[2][8], int blocks, int channels, int subbands); + /* Scale factors calculation with joint stereo support */ + int (*sbc_calc_scalefactors_j)(int32_t sb_sample_f[16][2][8], + uint32_t scale_factor[2][8], + int blocks, int subbands); const char *implementation_info; }; -- cgit