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Questions tagged [armv8]

This tag is for questions regarding specifically version 8 of the ARM architecture - 32-bit or 64-bit. Questions about the 64-bit ARM execution state or instruction set should be tagged with [arm64].

Version 8 of the ARM architecture introduced a new 64-bit execution state (AArch64) with a new 64-bit instruction set (A64) as well as retaining and extending the existing 32-bit execution state (AArch32) and its instruction sets A32 ("ARM") and T32 ("Thumb").

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ARMv8 odd infinite loop

So for an assignment I need to create an assembly program that finds the cube root of a floating point passed in from a binary file. Everything seems to work except at the end of the calculation there's an infinite loop. calcCR: stp x29,…
Eric
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arm assembly Invalid number of vectors

There were two questions about asm assembly in armv8. First,"Invalid number of vectors," my code is below. "prfm pldl1keep, [%7, #64] \n" "ld1 {v0.4s, v1.4s, v2.4s, v3.4s, v4.4s, v5.4s}, [%7], #48 \n" Second,"Mismatched register size…
冯剑龙
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Illegal instruction in assembly language (ARMv8)

So I have to write a program (the image above) which finds the max of a function on the domain of -6 <= x <= 5 and if I try to run or debug (gdb) the program the terminal outputs a message saying illegal instruction, specifically "in top ()". I'm…
StrawberryWaferCookie
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How can I install Python pip on the 'aarch64/armv8' platform?

I have a board which is powered by the Linux kernel. The board is of the aarch64/armv8 architecture. The board does not have apt-get, but it has easy_install. I tried to install using easy_install, but I got the following error (as root): cd…
Pushpa
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How to perform write back of dirty L1-L2 cache lines in ARMv8

I'm looking for a way to flush the L1-L2 cache using a kernel module. Is there a way to completely flush the whole cluster cache (4 core configuration) or even better, write back the dirty cache lines into main memory?
Κυριάκος Παρασκευάς
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Determining the first memory address

I'm working on a project to extract a key from memory. So i want to know the first memory address. For that i have samsung galaxy S7 with ARM processor ARMv8-A.I have taken a look at its kernel and i found following: #include…
BoB
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Xen ARM - How to transfer pages between domains by using grant table

So far, I can run Xen v4.9 on ARMv8 and have Dom0 and DomU run normally. Next, I want to transfer pages (change page ownership) from one domain to another by using grant table. But I always got bad page status while issuing hypercall to transfer…
Andy CHH
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Emulating a keystroke using ARMv8 assembly and Uinput

Update 07/23/2018: I have C-code with uinput implemented as follows: #include #include #include #include #include void emit(int fd, int type, int code, int val) { struct input_event…
shurburt
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VMINNM instruction in ARM

I would like to know how vminnm is working. Since the pseudo-code is bit unclear, I am not able to understand what is the exact function of this instruction. vminnm.f32 d3, d5, d13 where d5 = 0xffd5432100000000 d13 =…
Salim
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Corresponding asm code for ARMv8 aarch64

The below is code for X86-64 code which contains some assembly can you please help us to convert assembly for ARMv8 aarch64 __asm__ __volatile__ ("lock; cmpxchgw %1,%2" : "=a"(sPrev) : "q"(aWith), …
Jason
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How can I cross compile a 32-bit Linux kernel for ARM64 with armv8l-gnueabi?

I am working on compiling a 32-bit Linux kernel (4.4.x) to run on an ARM64 device. I am using armv8l-linux-gnueabihf gcc from Linaro. To compile the Linux kernel, I run the following commands: # run defconfig with COMPAT enabled to enable EL0 to run…
user641674
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armv8 RRX register usage

In one of my homework exercises, I'm asked to write an armv8 program that counts number of 1-bits in a register. Here's my implementation: .arch armv8-a // specifies the ARMv8 Architecture .text .align 2 // align to a multiple…
Christian Temple
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ACPI sleep state S3(suspend to ram) is supported on ARM64?

I am using ARMv8/ARM64 Architecture and booting Linaro v4.9 lsk . I want to use ACPI sleep state S3 like below: echo mem > /sys/power/state I got an error : Invalid argument The only strings present in /sys/power/state are "freeze" and "mem" I am…
logic seeker
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UADDL vs UADDL2 in Aarch64 NEON

NEON Assembly I am trying to understand the arm-v8 NEON. Let me tell an example what I am trying to do. I load 16 Bytes (pixels in uchar) from array A. Now I want to try "lengthening ADD" to ushort. From the documentation, I see UADDL and UADDL will…
Abid Rahman K
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assembly read from file segmentation

.data pn: .string "input.bin" string: .string "%f\n" buf_size = 8 alloc = -(16+buf_size)&-16 dealloc = -alloc buf_s = 16 .text .balign 4 .global main main: stp x29,x30,[sp,alloc]! mov x29,sp mov w0,-100 ldr…
user2912093
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