arm

问题 I know that the ARM PMU is partially implemented, thanks to the gem5 source code and some publications. I have a binary which uses perf_event to access the PMU on a Linux-based OS, under an ARM processor. Could it use perf_event inside a gem5 full-system simulation with a Linux kernel, under the ARM ISA? So far, I haven't found the right way to do it. If someone knows, I will be very grateful! 回答1: As of September 2020, gem5 needs to be patched in order to use the ARM PMU . Edit : As of

问题 I know that the ARM PMU is partially implemented, thanks to the gem5 source code and some publications. I have a binary which uses perf_event to access the PMU on a Linux-based OS, under an ARM processor. Could it use perf_event inside a gem5 full-system simulation with a Linux kernel, under the ARM ISA? So far, I haven't found the right way to do it. If someone knows, I will be very grateful! 回答1: As of September 2020, gem5 needs to be patched in order to use the ARM PMU . Edit : As of

问题 This question was originally posed for SSE2 here. Since every single algorithm overlapped with ARMv7a+NEON's support for the same operations, the question was updated to include the ARMv7+NEON versions. At the request of a commenter, this question is asked here to show that it is indeed a separate topic and to provide alternative solutions that might be more practical for ARMv7+NEON. The net purpose of these questions is to find ideal implementations for consideration into WebAssembly SIMD.

问题 Intel supports RDRAND (also known as Intel secure key) instruction for returning random numbers. And it's available in Ivy Bridge processors. I wonder, is there any ARM processor featuring instructions for on-chip hw random number generator functionally similar to RDRAND? And I have an additional question. In the Linux kernel (version 3.10), there are driver sources for hw random number generators in /linux/drivers/char/hw_random . (http://lxr.free-electrons.com/source/drivers/char/hw_random/

问题 Linux supports running 32-bit application, as long as kernel enables CONFIG_COMPAT the hardware supports the AArch32 I assume that 32-bit application must run in arm AArch32 execution state and if the environment has 32-bit application and 64-bit application. 32-bit application process -> arm state is AArch32 64-bit application process and kernel -> arm state is AArch64 Is it correct? If so, how does the Linux handle the AArch32 and AArch64 switch? Does the kernel know the running process is

问题 Linux supports running 32-bit application, as long as kernel enables CONFIG_COMPAT the hardware supports the AArch32 I assume that 32-bit application must run in arm AArch32 execution state and if the environment has 32-bit application and 64-bit application. 32-bit application process -> arm state is AArch32 64-bit application process and kernel -> arm state is AArch64 Is it correct? If so, how does the Linux handle the AArch32 and AArch64 switch? Does the kernel know the running process is

问题 Is there a way to perform a bitwise NAND operation on the bits in two registers in ARM7, either with the existing AND, OR and EOR operations or other instructions? 回答1: Sure; AND the two registers and then EOR the result with all 1's (for the negation). 回答2: and then mvn (move not). From GCC explorer int nand(int a, int b) { return ~(a & b); } nand(int, int): and r0, r0, r1 mvn r0, r0 bx lr 来源： https://stackoverflow.com/questions/21207561/nand-logical-bitwise-operation-in-arm

来源： https://stackoverflow.com/questions/64864035/any-cpuid-like-instruction-in-armv8

来源： https://stackoverflow.com/questions/40435552/arm-assembly-proper-way-to-push-pop-link-register-and-pc-in-a-subroutine-and-cal

来源： https://stackoverflow.com/questions/40435552/arm-assembly-proper-way-to-push-pop-link-register-and-pc-in-a-subroutine-and-cal