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目前顯示的是 9月, 2017的文章

NEON Basics

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From a software perspective, NEON technology is based on single instruction, multiple data (SIMD) operations in ARMv7 processors, which implement the advanced SIMD architecture extensions. From a hardware perspective, NEON is a separate hardware unit on Cortex-A series processors, together with a vector floating point (VFP) unit. If an algorithm can be designed to exploit dedicated hardware, performance can be maximized. SIMD Introduction SIMD is a computational technique for processing many data values in parallel using a single instruction, with the data for the operands packed into special, wide registers. Therefore, one instruction can do the work of many separate instructions on single instruction, single data (SISD) architectures. Many software programs operate on large data sets. Each element in a data set can be less than 32 bits. 8-bit data is common in video, graphics, and image processing, and 16-bit data in audio codecs. In these contexts, the operations

Free Schematic/PCB Tool_PADS Maker

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Mentor與Digi-key聯名的PADS Maker,可畫Schematic與PCB Layout 一些PADS裡面沒有的零件,除了自製,也可透過PartQuest搜尋Digi-key成千上百的零件庫獲得(https://partquest.com/) 註冊License & Download https://www.digikey.hk/zh/product-highlight/m/mentor-graphics/pads-maker Tutorial http://wiki.sdd.mentor.com/display/PADSInn 免費版當然有些限制 Name SplashScreen No.# of Connections Board Szie No.# of Layers PADS MakerPro Schematic MakerPro unlimited N/A N/A PADS Maker Schematic Maker 1500 N/A N/A PADS MakerPro Layout MakerPro unlimited 50 sq. inches 8 total/6 signal PADS Maker Layout Maker 1500 25 sq. inches 6 total/4 signal

error: ***.elf uses VFP register arguments, ***.o does not

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Xilinx Application Note : xapp1206 將-mfpu= vfpv3  -mfloat-abi= hard (default)設定成 -mfpu= neon  -mfloat-abi= softfp 會出現下列錯誤訊息 solution: step1: C/C++ Build -> Settings -> Tool Settings ARM v7 gcc compiler -> Miscellaneous Linker Flags : -c -fmessage-length=0 -MT"$@" -mcpu=cortex-a9 -mfpu= neon -mfloat-abi= softfp ARM v7 gcc linker -> Miscellaneous Linker Flags : -mcpu=cortex-a9 -mfpu= neon -mfloat-abi= softfp -Wl,-build-id=none -specs=Xilinx.spec step2 :  Modify this BSP’s Settings -> Overview -> Drivers -> ps7_cortexa9_0 Extra_compiler_flags : -mcpu=cortex-a9 -mfpu= neon -mfloat-abi= softfp -nostartfiles -Wall -Wextra