ARM Architecture Reference Manual ARMv7-A and ARMv7-R edition

Application Level Programmers’ Model
A2.2.1 Integer arithmetic
The instruction set provides a wide variety of operations on the values in registers, including bitwise logical
operations, shifts, additions, subtractions, multiplications, and many others. These operations are defined
using the pseudocode described in Appendix I Pseudocode Definition, usually in one of three ways:
By direct use of the pseudocode operators and built-in functions defined in Operators and built-in
functions on page AppxI-11.
By use of pseudocode helper functions defined in the main text. These can be located using the table
in Appendix J Pseudocode Index.
By a sequence of the form:
1. Use of the SInt(), UInt(), and Int() built-in functions defined in Converting bitstrings to
integers on page AppxI-14 to convert the bitstring contents of the instruction operands to the
unbounded integers that they represent as two's complement or unsigned integers.
2. Use of mathematical operators, built-in functions and helper functions on those unbounded
integers to calculate other such integers.
3. Use of either the bitstring extraction operator defined in Bitstring extraction on page AppxI-12
or of the saturation helper functions described in Pseudocode details of saturation on
page A2-9 to convert an unbounded integer result into a bitstring result that can be written to
a register.
A2-4 Copyright © 1996-1998, 2000, 2004-2008 ARM Limited. All rights reserved. ARM DDI 0406B