Questions tagged [arm]

ARM (formerly Advanced RISC Machine and Acorn RISC Machine) is a reduced instruction set computer (RISC) instruction set architecture (ISA) developed by Acorn Computers and extended by ARM Holdings. The ARM architecture is the most widely used 32-bit instruction set architecture in numbers produced.

More information can be found in the Wikipedia article on ARM Architecture and the ARM Reference Documents.

There are many different variants of the ARM assembler that have evolved over time. The notation can be confusing. For instance, arm7 and armv7, are completely different. The first is a CPU implementation; the second is a CPU architecture. The architecture, also called a family, is a set of machine instructions (or ISA for instruction set architecture) that are generally compatible. See: Wikipedia's list of ARM microarchitectures for more.

Related tags:

• thumb - the first version consisted of a reduced set of 16bit instructions. thumb2, introduced with armv6, includes a mix of 16 and 32bit instructions, extended further in armv7 such that it can do most things the normal ARM ISA can.
• neon - a SIMD extension for ARM CPUs
• cortex-m - an embedded ISA of the armv7 that only supports thumb2.
• cortex-a - the application version of armv7 ISA.
• arm64 - the eighth arm architecture (armv8) includes 64bit registers.
• trust-zone - a security feature in some armv6, armv8 and armv7 CPUs.
• amba - bus or interconnect specification used between CPUs and peripherals.
• swd - SWD (Serial Wire Debug) is a light weight version of JTAG designed for ARM MCUs.

Do not create tags such as cortex-m3. Often those posts apply to other cortex-m CPUs and/or the difference between the versions is important to understand. Also newer future CPUs may extend a specific CPU and questions in that tag maybe relevant.

If you are only posting to the tag arm try to give some specifics about the system you are using.