Hello,
Recently, I came back to digging into RTOS working principles at the lowest level on Cortex-M family processors. I understand the concept of SysTick (or other time base), SVC and PendSV as RTOS system exceptions. Though, one question is still itching…
Hey.
I read ARMv7-M Arch manual.
SHCSR register have SVCALLPENDED bit.
So that, It seem SVC is pendable.
But, 'Priority escalation' is written,
When the group priority of a pending synchronous fault or supervisor call is lower than or equal to…
I have been reading through the ARM documentation on memory and instruction barriers.
I have read that the single core ARMv7-M parts do not reorder instructions, as such the DSB and ISB are not needed, is this correct?
I have also read the same about…
Hi
Related to ARMv7-M architecture:
I am searching through all infocenter documents but still cannot find anything and answer this question: "When an exception is taken into account?" I mean, are exceptions only serviced after the current instruction…
I use DWT in Cortex-M4 to catch instructions that write or read memory contents and the problem is it doesn't stop immediately where I expect, it stops after 2-3 instruction later than where it should and the contents of registers are overwritten…
Hello people. I'm trying to do libgcc extraction for hard FPU's for k70 tower board. However, when I look at the libgcc library for arm targets, I find armv7-m, armv7e-m and armv7e-m-pic. I'm able to deduce from the armv7-m reference manual that the difference…
Hi,
I have a question regarding BASEPRI, BASEPRI_MAX, and DMBs as they relate to both the V7-M and V7E-M architectures.
Let's say I have the following assembly,
// stuff mrs r0, BASEPRI msr BASEPRI_MAX, #3 // more stuff
Is it necessary to put a…
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I have some assembly for Cortex M4 (Arm 7M Thumb), I want to enable an interrupt that is connected to a push button on an STM32 F407. It works, but for some reason when I enable the set enable register, the clear enable register also gets set ? Is…
Good day,
I want to refresh and (or) update my knowledge on ARMv7.
Is it true for ARMv7-M that when CPU starts execute one instruction, PC value has already been updated/is being updated in parallel with address of the next instruction? Or PC is updated…
Hi all,
I have little experience with bare metal programming at STM32 series and currently studying exception behavior in "ARMv-7m Architecture Reference Manual".
I'm confused about syn/asynchronous exception at B1-569. I have one question about…
Hello guys,
I am trying to verify some features of ARMv7-M3 in a software simulator platform for ARM. But this simulator only support ARMv7-A ISA.
Is ARMv7-M3 instructions compatible to ARMv7-A, especially thumb instructions?
Thank you very much.
According to ARM Architecture Procedure Call Standard (AAPCS) on the ARMv6-M, and ARMv7-M architecture in it says:
"Although the processor hardware allows SP to be at any word aligned address at function boundaries, standard programming practice…
Has an updated v7m architecture reference been published yet?
When we write such code as following, can keil compiler automaticly translate it into SIMD STM.
do{
*p++ = 1;
…
In software there are often cases where you need to have critical interrupts serviced. For example, for:
With the ARMv7-M architecture this can be achieved using nested interrupt handlers, but…
This article is a follow-on to Navigating the Cortex Maze. As a high-level overview, the earlier article provides an easy way-in to the ARM processor range. It covers Cortex-A (architecture ARMv7-A), Cortex-R (ARMv7-R) and Cortex-M (ARMv7-M).
But the…