What is a Thumb instruction set?
The Thumb instruction set is a subset of the most commonly used 32-bit ARM instructions. Thumb instructions are each 16 bits long, and have a corresponding 32-bit ARM instruction that has the same effect on the processor model. Thumb has all the advantages of a 32-bit core: 32-bit address space. 32-bit registers.
What is Thumb code?
Thumb code is implemented in the ARM processor as part of the instruction load and decode part of the pipeline. The ARM instruction decoder converts each 16-bit instruction into a 32-bit counterpart in the CPU, so the execution unit doesn’t know the difference.
What is Thumb mode operation?
The Thumb instruction set consists of 16-bit instructions that act as a compact shorthand for a subset of the 32-bit instructions of the standard ARM. When it’s operating in the Thumb state , the processor simply expands the smaller shorthand instructions fetched from memory into their 32-bit equivalents.
What is thumb How does the Thumb instruction set differ from ARM instruction set?
ARM and Thumb are two different instruction sets supported by ARM cores with a “T” in their name. ARM instructions are 32 bits wide, and Thumb instructions are 16 wide. Thumb mode allows for code to be smaller, and can potentially be faster if the target has slow memory.
What is Thumb-2 instruction?
Thumb-2 is an enhancement to the 16-bit Thumb instruction set. It adds 32-bit instructions that can be freely intermixed with 16-bit instructions in a program. The additional 32-bit instructions enable Thumb-2 to cover the functionality of the ARM instruction set.
How does the Thumb instruction set differ from ARM instruction set?
ARM instructions are 32 bits wide. Thumb instructions are 16 or 32-bits wide. The ARM instruction set is a set of 32-bit instructions providing a comprehensive range of operations. The Thumb instruction set provides better code density, at the expense of performance.
What is Thumb-2 instruction set?
What is Thumb How does the Thumb instruction set differ from ARM instruction set?
What is Thumb 2 instruction set?
What is Thumb instruction set what is the difference between thumb 1 and thumb 2?
Advanced Member level 1 Thumb = 16 bit instructions. Better performance / bigger code size in ARM mode vs Thumb. Thumb 2 is mixed 32/16 bit instructions. Somewhere in between the two.
What is Thumb instruction set what is the difference between Thumb 1 and Thumb 2?
Is the Thumb instruction set the same as arm?
Introduction to ARM thumb article continues below. The Thumb instruction set consists of 16-bit instructions that act as a compact shorthand for a subset of the 32-bit instructions of the standard ARM. Every Thumb instruction could instead be executed via the equivalent 32-bit ARM instruction.
Can a 32 bit instruction be executed on a thumb?
Every Thumb instruction could instead be executed via the equivalent 32-bit ARM instruction. However, not all ARM instructions are available in the Thumb subset; for example, there’s no way to access status or coprocessor registers.
How does a processor work in the thumb state?
When it’s operating in the Thumb state , the processor simply expands the smaller shorthand instructions fetched from memory into their 32-bit equivalents. The difference between two equivalent instructions lies in how the instructions are fetched and interpreted prior to execution, not in how they function.
How many instruction sets does an ARM processor have?
1 Answer 1. 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).