AWARE SYSTEMS
TIFF and LibTiff Mail List Archive

Thread

2021.05.02 00:36 "[Tiff] SIMD optimizations", by Larry Bank
2021.05.02 09:48 "Re: [Tiff] SIMD optimizations", by Even Rouault
2021.05.02 10:33 "Re: [Tiff] SIMD optimizations", by ZdPo Ster
2021.05.02 13:55 "Re: [Tiff] SIMD optimizations", by Bob Friesenhahn
2021.05.02 14:09 "Re: [Tiff] SIMD optimizations", by Even Rouault
2021.05.02 15:35 "Re: [Tiff] SIMD optimizations", by Larry Bank
2021.05.02 17:20 "Re: [Tiff] SIMD optimizations", by Even Rouault
2021.05.02 17:45 "Re: [Tiff] SIMD optimizations", by Larry Bank
2021.05.03 15:58 "Re: [Tiff] SIMD optimizations", by Even Rouault
2021.05.03 17:28 "Re: [Tiff] SIMD optimizations", by Larry Bank
2021.05.03 17:32 "Re: [Tiff] SIMD optimizations", by Even Rouault
2021.05.03 19:16 "Re: [Tiff] SIMD optimizations", by Jeff Breidenbach
2021.05.03 20:40 "Re: [Tiff] SIMD optimizations", by Bob Friesenhahn
2021.05.03 21:09 "Re: [Tiff] SIMD optimizations", by Even Rouault
2021.05.03 21:45 "Re: [Tiff] SIMD optimizations", by Bob Friesenhahn
2021.05.03 22:08 "Re: [Tiff] SIMD optimizations", by Even Rouault
2021.05.04 07:44 "Re: [Tiff] SIMD optimizations", by Roger Leigh
2021.05.04 07:50 "Re: [Tiff] SIMD optimizations", by Roger Leigh
2021.06.06 21:15 "Re: [Tiff] SIMD optimizations", by Roger Leigh
2021.05.03 21:44 "Re: [Tiff] SIMD optimizations", by Larry Bank
2021.05.03 21:55 "Re: [Tiff] SIMD optimizations", by Bob Friesenhahn
2021.05.03 22:50 "Re: [Tiff] SIMD optimizations", by Akira Urushibata
2021.05.04 17:34 "Re: [Tiff] SIMD optimizations", by Steve Underwood
2021.05.04 17:44 "Re: [Tiff] SIMD optimizations", by Larry Bank
2021.05.04 18:07 "Re: [Tiff] SIMD optimizations", by Toby Thain
2021.05.04 20:59 "Re: [Tiff] SIMD optimizations", by Michael Shiels
2021.05.04 21:02 "Re: [Tiff] SIMD optimizations", by Larry Bank
2021.05.05 01:14 "Re: [Tiff] SIMD optimizations", by Steve Underwood

2021.05.04 21:02 "Re: [Tiff] SIMD optimizations", by Larry Bank

There's no need to write asm code to make it fast. The problem is the awful way that the libtiff G4 encoder abuses memory. Clean C code will compile into a good result for G4 encoding and decoding. The decode side of the libtiff G4 codec isn't terrible because it's not doing anything awful with memory. The right way to count runs of 1-bit pixels is to use the CLZ (count leading zeros) instruction on the native integer size. GCC provides an intrinsic for it and has efficient code for systems that are missing this instruction (very few).

Larry B.