arm

问题 what is tail chaining of Interrupts which is supported by NVIC in ARM Cortex M3. 回答1: Tail-chaining is back-to-back processing of exceptions without the overhead of state saving and restoration between interrupts. The processor skips the pop of eight registers and push of eight registers when exiting one ISR and entering another because this has no effect on the stack contents. Cortex™-M3 Technical Reference Manual Which basically means, handling pending interrupts without repeating the

问题 I have created an ARM template and am using it to: Create a resource group. Create and Application Service. Deploy code from GitHub (repoUrl) to said Application Service. All works wonderfully when I place my project inside GitHub but we are using VSTS Git to hold our code. I know I can create a VSTS jobs that will do this for me and this is the track we will get to again however we need to be able to run these ARM templates from our developer machines, running direct from our Visual Studios

问题 I'd like to use two array passed into a C function as below in assembly using a GCC compiler (Xcode on Mac). It has been many years since I've written assembly, so I'm sure this is an easy fix. The first line here is fine. The second line fails. I'm trying to do the following, A[0] += x[0]*x[0], and I want to do this for many elements in the array with different indices. I'm only showing one here. How do I use a read/write array in the assembly block? And if there is a better approach to do

问题 Is there a simple way to define a symbol for the Android NDK toolchain's assembler from the Android.mk file? My objective is to be able to build a native library made up from several .C and .s (assembler) files compiled and tuned for either ARMV6 or ARMV7A EABIS, with all the required conditional compilation driven by simply modifying the APP_ABI value on the Application.mk file. First I have succesfully used the ifeq() directives available in Android.mk to query the value of the APP_ABI

问题 I am learning ARM Assembly, and I am stuck on something right now. I know about the Link Register, which if I'm not wrong holds the address to return to when a function call completes. So if we have something like that (taken from the ARM documentation): 0 | here 1 | B there 2 | 3 | CMP R1, #0 4 | BEQ anotherfunc 5 | 6 | BL sub+rom ; Call subroutine at computed address. So, if we think of the column at the left as addresses of each instruction, then after the B there at address 1, the Link

问题 all. I try to get PMUs information such as Instructions, Cycle, Cache miss and etc. on 2nd Nexus7 with Krait CPU. The perf tool is not working correctly. Therefore, I am using follow a sample source code in perf_event tutorials. #include <stdlib.h> #include <stdio.h> #include <unistd.h> #include <string.h> #include <sys/ioctl.h> #include <linux/perf_event.h> #include <asm/unistd.h> static long perf_event_open(struct perf_event_attr *hw_event, pid_t pid, int cpu, int group_fd, unsigned long

问题 What is the earliest version of Visual Studio (C++) that supports the ARM NEON Intrinsics, if any ? 回答1: Visual Studio 2012 supports NEON intrinsics (as well as ARMv6 intrinsics) when compiling for Windows-on-ARM. Visual Studio 2008 supported only ARMv5 DSP, XScale, and WMMX instructions when compiling for Windows Mobile. 来源： https://stackoverflow.com/questions/11839780/arm-neon-intrisics-support-in-visual-studio

问题 I am trying to port my own driver to a Beagle board xm arm-cortex-A8 . While porting I am trying to figuring out how the .ko file actually builds. In our Makefile we only have a command to build an .o file. How is a .ko file built? Using linux- 2.6.38.8 kernel and trying to configure my driver for my kernel. 回答1: The kernel kbuild module document has lots of information on how to build an external module. If you have Raspberian or some other embedded ARM Linux, you will need to get the source

问题 I have a small question about using ASM in c. I want to execute the instruction: LDR PC,=0x123456 This gives me the error "unexpected token in operand". asm("LDR PC,=0x123456"); This gives "invalid constraint". asm("LDR PC," : "m" (0x123456)); What's the right way to do this? 回答1: You are using this: asm("LDR PC,=0x123456"); This is not a standard ARM assembly instruction, but a pseudo-instruction provided as a compiler extension. This pseudo-instruction is converted to other assembly

问题 I have a x86 assembly code: unsigned int oldval; __asm__ __volatile__ ( "movl $1, %0 \n" "lock xaddl %0, (%1) \n" : "=a" (oldval) : "b" (n))l; return oldval; and I want to translate it into arm assembly. Is there any prefix in arm assembly that does the same thing as "lock" here? 回答1: I don't know ARM, but from glossing over the manual, the following should approximate your atomic exchange-and-add: foo: LDREX R1, [R0] ; R0 is "n", load linked ADD R2, R1, 1 ; R2 = R1 + 1 STREX R3, R2, [R0] ;