2.5. Loading constants into registers

You cannot load an arbitrary 32-bit immediate constant into a register in a single ARM instruction without performing a data load from memory. This is because ARM instructions are only 32 bits long. Thumb instructions have a similar limitation.

You can also include many commonly-used constants directly as operands within data processing instructions, without a separate load operation.

You can load any 32-bit value into a register with a data load, but there are more direct and efficient ways to load many commonly-used constants.

In ARMv6T2 and above, you can also load any 32-bit value into a register with two instructions, a MOV followed by a MOVT. You can use a pseudo-instruction, MOV32, to construct the instruction sequence for you.

The following sections describe:

Copyright © 2002-2005 ARM Limited. All rights reserved.ARM DUI 0204F