Here’s how I understand the terms. Bootrom Bootrom (or Boot ROM) is a small piece of mask ROM or write-protected flash embedded inside the processor chip. It contains the very first code which is executed by the processor on power-on or reset. Depending on the configuration of some strap pins or internal fuses it may … Read more
You can edit the file: C:\Program Files (x86)\MSBuild\Microsoft.Cpp\v4.0\V110\Platforms\ARM\Microsoft.Cpp.ARM.Common.props In the <PropertyGroup> section add the line: <WindowsSDKDesktopARMSupport>true</WindowsSDKDesktopARMSupport> before </PropertyGroup> And that’s all, you can build ARM desktop apps with VS2012.
You say “different than what we think of”, as if everyone thinks in the same way 🙂 I would guess that you are coming from low-end microcontrollers which often have separate program and data address spaces. On ARM the situation is different: program code, data and peripheral registers all reside in the same flat 32-bit … Read more
In order to add your own machine, you need at least create one source file, containing the parameters and peripherals of your machine. After that, add a entry inside Makefile.objs, under qemu/hw/arm/. STM32 P103 machine entry. Let’s take as example Olimex STM32 P103 Development Board: Olimex STM32 P103 Development Board code. In lines 105 and … Read more
Sorry, not going to give you a straight-out example like you’re asking, because as you are already looking through the Linux source code, you have plenty of those to go around, and they don’t appear to help. No shame in that – every sane person is at least initially confused by memory access ordering issues … Read more
Register banking refers to providing multiple copies of a register at the same address. Taken from section 1.4.6 of the arm docs The term is referring to a solution for the problem that not all registers can be seen at once. There is a different register bank for each processor mode. The banked registers give … Read more
Oh, ARM and their silly naming… It’s a common misconception, but officially there’s no such thing as a “Thumb-2 instruction set”. Ignoring ARMv8 (where everything is renamed and AArch64 complicates things), from ARMv4T to ARMv7-A there are two instruction sets: ARM and Thumb. They are both “32-bit” in the sense that they operate on up-to-32-bit-wide … Read more
An ABI (Application Binary Interface) is a standard that defines a mapping between low-level concepts in high-level languages and the abilities of a specific hardware/OS platform’s machine code. That includes things like: how C/C++/Fortran/… data types are laid out in memory (data sizes / alignments) how nested function calls work (where and how the information … Read more
There are quite some difference between the two. Neon is a SIMD (Single Instruction Multiple Data) accelerator processor as part of the ARM core. It means that during the execution of one instruction the same operation will occur on up to 16 data sets in parallel. Since there is parallelism inside the Neon, you can … Read more
The ARM processor has 2 instruction sets, the traditional ARM set, where the instructions are all 32-bit long, and the more condensed Thumb set, where most common instructions are 16-bit long (and some are 32-bit long). Which instruction set to run can be chosen by the developer, and only one set can be active (i.e. … Read more