166 questions
- Bountied 0
- Unanswered
- Frequent
- Score
- Trending
- Week
- Month
- Unanswered (my tags)
2
votes
1
answer
90
views
Why are J1 and J2 used with XOR in ARMv6-M BL instruction immediate calculation?
I’m trying to understand how the BL instruction is decoded in the ARMv6-M architecture.
The part I don’t get is in the imm32 calculation: the values of I1 and I2 are derived using J1 and J2, but they’...
1
vote
1
answer
467
views
How do you `docker buildx build` for ARM v6 on QEMU emulated platforms that present as arm7l to the build container?
When you build a Docker image with docker buildx build and specify '--platform=linux/arm/v6', the build container runs as arm7l rather than the expected arm6l, which creates issues if the build ...
1
vote
0
answers
413
views
How do I run a C++20 program on a Raspberry Pi 1B?
The Raspberry Pi 1B has an armv6 architecture. I have gone to https://github.com/tttapa/docker-arm-cross-toolchain and installed the armv6-rpi-linux-gnueabihf compiler toolchain on a more modern Linux ...
0
votes
1
answer
106
views
Atags are non-sensical when booting custom RaspberryPi kernel
I'm working on a kernel for a RaspberryPi 1B+ and I'm having some trouble with the ATAGS. My orientation for the implementation was this page.
The implementation for parsing looks something like this:
...
0
votes
1
answer
148
views
in ARMv6 assembly one code is not working, but the modified version works. Why?
i have a programm in armv6 assembly which calculates the result of (x +y)^2
this code doesn't work, and returns: "Unsupported ARM syscall: 0xffffffdf"
.global _start
.text
_start:
MOV r0,...
0
votes
0
answers
186
views
runtime detection whether ARMv7 ELF binaries can be loaded on ARMv6 host
Consider a host application that has been compiled for armv6 (think: Raspbian) and can dlopen() extensions/plugins.
Some of these plugins might be compiled for armv7.
If the host application is ...
0
votes
1
answer
2k
views
pyelftool get symbol absolute address
My Goal: use pyelftool to retrieve variables absolute placement and functions absolute address from an elf file to automatize breakpoint placement for whitebox testing.
my code:
import elftools
from ...
0
votes
1
answer
140
views
ATSAMD GCLK[x] for more Peripherals
is it possible to use one GCLK for more peripherals?
The ATSAMD09C13 have six GCLK Generators but this isn ́t enougth.
This example works:
GCLK->CLKCTRL.reg = GCLK_CLKCTRL_ID(SERCOM0_GCLK_ID_CORE) |
...
-1
votes
1
answer
2k
views
Clarity About TST Instruction - ARM Assembly
So here I have the following code (ARMv6 assembly):
wait$:
ldr r2,[r0,#24] //read 32 bits from addr + 24 in r0 and store in r2
tst r2,#0x80000000 //????
bne wait$
I understand all of the ...
1
vote
0
answers
207
views
ARMv6 calling convention with args in r0,r3 and return in r1
I am analyzing a binary taken from a STM32 SoC (ArmV6)
and it uses a to me unknown calling convention for small functions.
First argument in r0, second argument in r3 and return in r1. (In my binary ...
0
votes
1
answer
137
views
Why are non-consecutive loads faster, even when the cache miss penalty is guaranteed to be zero?
Background:
I wrote a function in C and compiled it with arm-none-eabi-gcc (7-2018-q2-update).
The generated assembly code for the loop body looks like it should take 20 cycles per iteration,
...
0
votes
2
answers
941
views
Cortex-M0+ not responding to PendSV
I'm running on a Raspberry Pi Pico (RP2040, Cortex-M0+ core, debugging via VSCode cortex-debug using JLink SWD), and I'm seeing strange behaviour regarding PendSV.
Immediately prior, the SVCall ...
0
votes
1
answer
356
views
Macro for optimization level (ARMCC V6)
There are predefined macros such as __OPTIMIZE__ (defined in all optimizing compilations) and __OPTIMIZE_SIZE__ (defined if the compiler is optimizing for size).
I use these macros to check if the ...
user avatar
user9387989
5
votes
0
answers
1k
views
Building Python wheels in Docker for Raspberry Pi Zero on x86_64 machine
I'm hoping this is an appropriate venue for my question. There's a lot of pieces to this puzzle.
I'm building a container using Docker that is destined to run on a Raspberry Pi Zero. The RPi Zero has ...
2
votes
0
answers
882
views
Problems installing OpenMediaVault 5 on Raspberry Pi 1
BTW, I am trying to install OpenMediaVault on a Raspberry Pi 1, however, whenever I try and install OpenMediaVault on a Raspberry Pi 1, I get problems with the monit package, the FastCGI Process ...