arm

Compute clock cycle count on ARM Cortex-a8 BeagleBone Black

由 允我心安 提交于 2020-01-13 06:11:09
问题 I want to compute the clock cycle count for a specific function inside my c code which is going to be compiled and run on BeagleBone Black. I have no idea how I can do this. I searched over the web and I found this instruction: Clock Read method on Arndale board: Step-1: Inserting kernel module to enable user space access to PMU counters. Untar the attached file “arndale_clockread.tar.bz2” which is having Makefile and enableccnt.c. In Makefile change the “KERNELDIR” with your kernel source

Compute clock cycle count on ARM Cortex-a8 BeagleBone Black

由 不羁岁月 提交于 2020-01-13 06:10:28
问题 I want to compute the clock cycle count for a specific function inside my c code which is going to be compiled and run on BeagleBone Black. I have no idea how I can do this. I searched over the web and I found this instruction: Clock Read method on Arndale board: Step-1: Inserting kernel module to enable user space access to PMU counters. Untar the attached file “arndale_clockread.tar.bz2” which is having Makefile and enableccnt.c. In Makefile change the “KERNELDIR” with your kernel source

qt arm交叉编译命令

由 拈花ヽ惹草 提交于 2020-01-13 04:52:51
arm 版本配置命令 #!/bin/sh ../configure -prefix /home/mmm/dev/tools/qt_arm_5126 -verbose -opensource -release -confirm-license -xplatform linux-arm-gnueabihf-g++ -shared -qt-zlib -qt-libjpeg -qt-libpng -make libs -linuxfb -eglfs -no-cups -no-iconv -no-pch -no-opengl -no-openssl qmake 配置 # # qmake configuration for building with arm-linux-gnueabihf-g++ # MAKEFILE_GENERATOR = UNIX CONFIG += incremental QMAKE_INCREMENTAL_STYLE = sublib include(../common/linux.conf) include(../common/gcc-base-unix.conf) include(../common/g++-unix.conf) # modifications to g++.conf QMAKE_CC = arm-linux-gnueabihf-gcc QMAKE

Loads and stores reordering on ARM

由 試著忘記壹切 提交于 2020-01-13 04:23:06
问题 I'm not an ARM expert but won't those stores and loads be subjected to reordering at least on some ARM architectures? atomic<int> atomic_var; int nonAtomic_var; int nonAtomic_var2; void foo() { atomic_var.store(111, memory_order_relaxed); atomic_var.store(222, memory_order_relaxed); } void bar() { nonAtomic_var = atomic_var.load(memory_order_relaxed); nonAtomic_var2 = atomic_var.load(memory_order_relaxed); } I've had no success in making the compiler put memory barriers between them. I've

ARM发展历史

由 风格不统一 提交于 2020-01-12 18:34:08
行业 　　 ARM 位于无线生态价值链的最顶端，为整个无线生态提供多种应用处理器 IP 研发外包，将长期受益于无线生态的发展演进。 公司 　　 ARM 是全球领先的半导体知识产权（ IP ）商，公司设计高性能、廉价、耗能低的 RISC 处理器方案，并将其授权给第三方合作伙伴，第三方合作生产基于 ARM 架构芯片， ARM 则按芯片价格与出货量获得一次性授权入门费与版税提成， 2011 年营收 7.85 亿美元 , 同比增 21% ，税前利润 3.67 亿美元，同比增 37% 。 　　 ARM 授权费 + 版税的商业模式将受益于营业杠杆，授权费收入将覆盖大部分新技术开发的运营费用，后续绝大部分的版税收入将成为公司利润，公司预计中期来看，版税收入增长将高于授权业务以及成本。 估值 　　截止 2012 年 8 月 30 日收盘，公司 TTM 市盈率 56.8 倍，对应分析师预期 2012 年盈利大约 37 倍， 2013 年盈利大约 32 倍， 5 年预期 PEG 约在 1.89 倍，公司的长期增长将取决于智能机、平板电脑等现有市场份额和增长，以及新领域的拓展。 风险 　　 ARM 商业模式决定起将受到整个半导体行业高周期的影响； ARM 在智能手机、平板电脑的高市场份额将受到英特尔、 MIPS 的长期竞争；同时作为一家英国公司，面临着汇率风险，即营收成本不匹配，绝大部分收入来自美元

Which mode does the SVC handler start in?

由 ↘锁芯ラ 提交于 2020-01-12 09:59:52
问题 Which mode does the ARM SVC handler start in? Basically, I want to know which mode the ARM core is in when an SVC exception is raised? Can't seem to find it in the ARM ARM, but my guess would be that it starts in Supervisor . 回答1: Are you talking about the SWI handler? Yes, I see some places they refer to it as the SWI instruction but sometimes the SVC instruction. Note: In older versions of the ARM architecture, SVC was called SWI, Software Interrupt. From the ARM ARM Exception type Mode

ARM11 Translation Lookaside Buffer (TLB) usage?

由 僤鯓⒐⒋嵵緔 提交于 2020-01-12 07:44:11
问题 Is there a decent guide explaining how to use the TLB ( Translation Lookaside Buffers ) tables on an ARM1176JZF-S core? Having looked over the technical documentation for the that ARM platform I still have no clue what a TLB is or what it looks like. As far as I understand, each TLB entry maps a virtual page to a physical page, allowing remapping and controlling memory permissions. Apart from that, I have absolutely no clue on how to use them. What structure does a TLB entry have? How do I

ARM11 Translation Lookaside Buffer (TLB) usage?

由 别等时光非礼了梦想. 提交于 2020-01-12 07:44:06
问题 Is there a decent guide explaining how to use the TLB ( Translation Lookaside Buffers ) tables on an ARM1176JZF-S core? Having looked over the technical documentation for the that ARM platform I still have no clue what a TLB is or what it looks like. As far as I understand, each TLB entry maps a virtual page to a physical page, allowing remapping and controlling memory permissions. Apart from that, I have absolutely no clue on how to use them. What structure does a TLB entry have? How do I

CPU dependent code: how to avoid function pointers?

由 我只是一个虾纸丫 提交于 2020-01-12 06:15:27
问题 I have performance critical code written for multiple CPUs. I detect CPU at run-time and based on that I use appropriate function for the detected CPU. So, now I have to use function pointers and call functions using these function pointers: void do_something_neon(void); void do_something_armv6(void); void (*do_something)(void); if(cpu == NEON) { do_something = do_something_neon; }else{ do_something = do_something_armv6; } //Use function pointer: do_something(); ... Not that it matters, but I

Using objdump for ARM architecture: Disassembling to ARM

由 有些话、适合烂在心里 提交于 2020-01-12 04:54:27
问题 I have an object file and am trying to disassemble it. When I use: objdump -d example.o I get an assembly in code in the file format of elf64-x86-64 . I am trying to disassemble this into ARM, how do I go about doing this? 回答1: If you want to do disassemble of ARM code, you'd better have an ARM tool chain, this is what I got: http://bb.osmocom.org/trac/wiki/toolchain After you have this, you can use arm-elf-objdump instead of objdump. The command I used is arm-elf-objdump -D -b binary -marm
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