• Correct usage of the NSTable bit in aarch64/armv7a LPAE

    Vincent Siles
    Vincent Siles

    I'm porting our armv7a-short descriptor OS to LPAE and aarch64. In the short descriptor MMU, the "NS" bit can only be found in the first level of the MMU (I'll call it the SECTION level), meaning that only a single page cannot be tagged as NS, a whole…

    • Answered
    • over 3 years ago
    • Processors
    • Cortex-A / A-Profile forum
  • aarch64 kernel using aarch32 page tables

    Vincent Siles
    Vincent Siles

    Hi !

    I'm trying to update my custom kernel, working with short or long descriptor in armv7a to a target supporting armv8.

    My current setup uses TTBR0 to point to the PL0 page table and TTBR1 to point to the PL1 page table.

    At the moment, I sometimes…

    • Answered
    • over 3 years ago
    • Processors
    • Cortex-A / A-Profile forum
  • v8.2 Atomic Instructions

    nathanma32
    nathanma32

    Hello,

    In the new v8.2, atomic instructions are presented which can be an alternative to the previous ld/st exclusive and other similar instructions.

    My question is what is the advantage of using atomic instructions instead of for example a pair of ld…

    • Answered
    • over 3 years ago
    • Processors
    • Cortex-A / A-Profile forum
  • Processor Modes in cortex-A57

    Ajeesh
    Ajeesh

    Hi,

    I have done some basic assembly in Armv7-A processors (cortex A9). The version of ARM supports modes like User, sys, SVC etc. Does the ARMv8 also has the similar modes? Where can i find the details. Please point me to the documents if any.

    Regards…

    • Answered
    • over 3 years ago
    • Processors
    • Cortex-A / A-Profile forum
  • Porting code from Cortex-A9 to Cortex-A57

    Ajeesh
    Ajeesh

    Hi,

    I have been using I.MX6Q Sabre sd board (cortex-a9 ). I build image with my own start script and ld script. The image was loaded with u-boot. Now i would like to do the Same with Renesas R-Car M3(cortex A-57). How would i go about this? Can i use the…

    • Answered
    • over 3 years ago
    • Processors
    • Cortex-A / A-Profile forum
  • Getting ERROR "unknown mnemonics for UQSUB8 instruction"

    Drashti Parikh
    Drashti Parikh

    Hi community,

    I have tried to compile the source code for openVG
    I have given proper cross compiler which is required by the platform still I am getting the error of unknown mnemonics for the instruction UQSUB8

    Environment:

    - Linux platform

    - CROSS COMPILE…

    • Answered
    • over 4 years ago
    • Processors
    • Cortex-A / A-Profile forum
  • Spin-lock implementation for Aarch64 -- how to enforce acquire semantics?

    Olivier Delande
    Olivier Delande

    Here is a minimal C implementation of a spinlock "lock" operation using GCC's built-in atomics:

    #include <stdbool.h>
    
    void spin_lock(bool *l) {
      while (__atomic_test_and_set(l, __ATOMIC_ACQUIRE))
        ;
    }
    

    I am concerned…

    • Answered
    • over 4 years ago
    • Processors
    • Cortex-A / A-Profile forum
  • Is it possible to implement EL3 AArch64 and change it later to EL3 AArch32?

    유영현
    유영현

    I was reading the ARM architecture reference manual... and thought

    Is it possible to implement EL3 AArch64 and change it later to EL3 AArch32?

    How to change is...

    If I start on cold reset, it will start at EL3 AArch64.

    Right after the cold reset, I set the…

    • over 4 years ago
    • Processors
    • Cortex-A / A-Profile forum
  • Building EFI applications with UDK14/15 targeted to AARCH64 using Visual Studio 2012/2015//WinDDK 8.1 ARM Compiler

    Ravikanth
    Ravikanth

    Hello,

    Can we build EFI applications with UDK14/UDK15 targeted to AARCH64 using Visual 2012/2015/WinDDK8.1 ARM Compiler in windows platform?

    I have tried building the UDK 14/15 code using VS2012 ARM Compiler and I am receiving __rd_udiv,__rt_udiv64 kind…

    • over 4 years ago
    • Software Tools
    • Arm Development Studio forum
  • Why in A64 the coprocessor is removed?

    Victor
    Victor

    For the view of architecture, why the coprocessor is removed for A64 instruction set?

    • Answered
    • over 5 years ago
    • Processors
    • Cortex-A / A-Profile forum
  • ARMv8-A AArch64软件浮点库支持问题

    steven
    steven

    ARMv8-A AArch64 ABI中强制使用了硬浮点,目前暂未提供软浮点ABI支持。请问如果Cortex-A53去掉了硬浮点部件,应用上如何支持浮点运算呢?ARM在软浮点的ABI支持上是否有计划?

    • over 5 years ago
    • 中文社区
    • 中文社区论区
  • AArch64 x30和LR有什么区别

    Jorney
    Jorney

    The X30 general-purpose register is used as the procedure call link register. <ARM Architecture Reference Manual ARMv8, for ARMv8-A architecture profile>

    如上,X30用作link register. 那么X30和LR是什么区别,在AArch64模式下是否是同一个寄存器。

    • over 5 years ago
    • 中文社区
    • 中文社区论区
  • AARCH64 assembly syntax for ARMCLANG

    cesare
    cesare

    Hello,

    where can I get documentation for the AARCH64 and NEON64 assembly syntax for armclang (internal assembler)

    I have some issues when compiling my GNU assembly code with armclang.

    For example, the instruction:

    MOV v0.2d[0], x4

    reports "error: invalid…

    • Answered
    • over 5 years ago
    • Processors
    • Cortex-A / A-Profile forum
  • How to measure program execution time in ARM Cortex-A53 processor?

    Rajeev Verma
    Rajeev Verma

    Hi,

    I was using following method to read clock in cortex-a15:

           static void readticks(unsigned int *result)

            {

                struct timeval t;…

    • Answered
    • over 5 years ago
    • Processors
    • Cortex-A / A-Profile forum
  • A strange problem in porting secure os in v8 secure EL1

    Steven Meng
    Steven Meng

    Hi, ARM experts:

        When we porting a secure os in 32bit mode in v8 secure EL1(our EL3 is running in AARCH 64bit mode), we got a strange problem:

        

        When start booting secure os in secure EL1, the bootstrap code…

    • Answered
    • over 5 years ago
    • Processors
    • Cortex-A / A-Profile forum
  • C代码中内嵌汇编代码问题,大家帮忙看看。

    caotianxiang
    caotianxiang

    1、Arm compiler 6 下target分为两种:aarch64-arm-none-eabi(对应AArch64执行状态)和armv8a-arm-none-eabi(对应AArch32执行状态),当target设置为aarch64-arm-none-eabi时无法使用内嵌汇编指令QADD、QADD16等,当target设置为armv8a-arm-none-eabi时可以使用内嵌汇编指令QADD、QADD16等,这应该是和两种执行状态各种的指令集相关,但是前面提前的可以编译时在Debug下…

    • over 5 years ago
    • 中文社区
    • 中文社区论区
  • Do Aarch64 char parameters and returns have the top undefined?

    daith
    daith

    If a char parameter is passed to a routine in Aarch64 is the top of the word undefined? and is the same true for if a char value is returned? I think the answer is yes but it would be good to be certain. This means if the char is used in some arithmetic…

    • Answered
    • over 5 years ago
    • Software Tools
    • Arm Development Studio forum
  • Linaro Kernel that AArch32 applications run in EL0

    Manabu Nakamura
    Manabu Nakamura

    Hello everyone.

    Would you let me know how to build Linaro Kernel that AArch32 applications run in EL0?

    I'm trying to build Linaro Kernel while seeing the following site.

    http://releases.linaro.org/latest/openembedded/juno-lsk

    I would like to build Linaro…

    • Answered
    • over 6 years ago
    • Software Tools
    • Arm Development Studio forum
  • AA64与ARM-V7 LPAE的MMU Table

    颠拐
    颠拐

    哪个亲知道ARM-V8的AA64与ARM-V7 LPAE的MMU Table差距多少?

    ARM DS-5自带的example看起来挺麻烦的,关键是没有run起来,光看代码没有效果!

    • over 6 years ago
    • 中文社区
    • 中文社区论区
  • Assembly language examples of ARMv8 AArch64 instruction set

    hgli
    hgli

    Hello everyone,

    I hope to find some assembly language examples of ARMv8 AArch64 instruction set.

    Where can I find them?

    Thank you in advance !

    • Answered
    • over 6 years ago
    • Processors
    • Cortex-A / A-Profile forum
  • 寻找 ARMv8 AArch64 汇编例程

    hgli
    hgli

    请问:

    哪里可以找到ARMv8 AArch64 汇编例程?

    提前致谢!

    • over 6 years ago
    • 中文社区
    • 中文社区论区
  • ARM64 Linaro toochain Link error ( R_AARCH64_LD_PREL_LO19 )

    Sreenath P V
    Sreenath P V

    Hi Experts,

    I am getting following linker error from Linaro aarch64 tool chain( aarch64-linux-gnu-gcc, gcc-linaro-aarch64-linux-gnu-4.8-2014.03_linux),  for our code which uses  pBitReverseIndex, pSignTable  global pointers which is declared out side the…

    • over 6 years ago
    • Software Tools
    • Arm Development Studio forum
  • 在64bit下,C程序可以使用内联汇编吗?

    chinatiger
    chinatiger

    比如:

    C函数中:使用asm volatile ("MRC......")之类的。

    使用Aarch64 gcc编译时,会报错吗?

    best wishes,

    • Answered
    • over 6 years ago
    • 中文社区
    • 中文社区论区
  • Switching from AARCH64 to AARCH32

    Biswa Singh
    Biswa Singh


    Hi,

    We are trying to switch from AARCh64 to AARCH32 using the following command.

    sudo su

    cd /root

    schroot  -c armhf-trusty

    But it says command not found. We are using munimal version of AARCH64 from linaro and prebuild board recovery image 4.0.

    What is…

    • Answered
    • over 6 years ago
    • Open Source Software and Platforms
    • Arm Development Platforms forum
  • Facing issues while using debugger ARMAEMv8-A_MP_0 on DS5. How to solve it?

    Nabaneeta
    Nabaneeta

    I am using ARM DS5 Ultimate Edition (Version 5.18.0)

    Target aarch64-arm-none-eabi is being used for compilation.
    I am trying to run the .axf on ARMAEMv8-A_MP_0.
    While running the .axf I am getting this error:-
    ERROR(CMD426): Cannot find symbol to start or…

    • Answered
    • over 6 years ago
    • Software Tools
    • Arm Development Studio forum
<>