How can ARM's MOV instruction work with a large number as the second operand?

Question

I just begin to study ARM assembly language, and am not clear about how to use MOV to transfer an immediate number into a register.

From both the ARM reference manual

Answer 1

One possibility is that the ARM assembler throws away the significant bits of the number and uses only the lowest FF.

The MOV instruction is a staple in many CPU instruction sets, and usually the assembler resolves the size of the target register and the immediate value being supplied.

For example the following MOV instructions from the x86 set are

MOV BL, 80h, ; 8bit
MOV BX, ACACh ;16bit
MOV EBX, 12123434h ; 32bit