SSE2 SIMD implementation of Huffman encoding
Full-color compression speedups relative to libjpeg-turbo 1.4.2:
2.8 GHz Intel Xeon W3530, Linux, 64-bit: 2.2-18% (avg. 9.5%)
2.8 GHz Intel Xeon W3530, Linux, 32-bit: 10-25% (avg. 17%)
2.3 GHz AMD A10-4600M APU, Linux, 64-bit: 4.9-17% (avg. 11%)
2.3 GHz AMD A10-4600M APU, Linux, 32-bit: 8.8-19% (avg. 15%)
3.0 GHz Intel Core i7, OS X, 64-bit: 3.5-16% (avg. 10%)
3.0 GHz Intel Core i7, OS X, 32-bit: 4.8-14% (avg. 11%)
2.6 GHz AMD Athlon 64 X2 5050e:
Performance-neutral (give or take a few percent)
Full-color compression speedups relative to IPP:
2.8 GHz Intel Xeon W3530, Linux, 64-bit: 4.8-34% (avg. 19%)
2.8 GHz Intel Xeon W3530, Linux, 32-bit: -19%-7.0% (avg. -7.0%)
Refer to #42 for discussion. Numerous other approaches were attempted,
but this one proved to be the most performant across all platforms.
This commit also fixes #3 (works around, really-- the clang-compiled version
of jchuff.c still performs 20% worse than its GCC-compiled counterpart, but
that code is now bypassed by the new SSE2 Huffman algorithm.)
Based on:
https://github.com/mayeut/libjpeg-turbo/commit/2cb4d41330e1edc4469f6b97ba73b73abfbeb02f
https://github.com/mayeut/libjpeg-turbo/commit/36c94e050d117912adbff9fbcc6fe307df240168
diff --git a/simd/jsimd.h b/simd/jsimd.h
index c0de7e7..04277fc 100644
--- a/simd/jsimd.h
+++ b/simd/jsimd.h
@@ -2,9 +2,10 @@
* simd/jsimd.h
*
* Copyright 2009 Pierre Ossman <ossman@cendio.se> for Cendio AB
- * Copyright (C) 2011, 2014-2015 D. R. Commander
+ * Copyright (C) 2011, 2014-2016 D. R. Commander
* Copyright (C) 2013-2014, MIPS Technologies, Inc., California
* Copyright (C) 2014 Linaro Limited
+ * Copyright (C) 2015 Matthieu Darbois
*
* Based on the x86 SIMD extension for IJG JPEG library,
* Copyright (C) 1999-2006, MIYASAKA Masaru.
@@ -828,3 +829,9 @@
EXTERN(void) jsimd_idct_float_sse2
(void * dct_table, JCOEFPTR coef_block, JSAMPARRAY output_buf,
JDIMENSION output_col);
+
+/* Huffman coding */
+extern const int jconst_huff_encode_one_block[];
+EXTERN(JOCTET*) jsimd_huff_encode_one_block_sse2
+ (void * state, JOCTET *buffer, JCOEFPTR block, int last_dc_val,
+ c_derived_tbl *dctbl, c_derived_tbl *actbl);