What is MOV in ARM assembly?

What is MOV in ARM assembly?

The MOV instruction copies the value of Operand2 into Rd . In certain circumstances, the assembler can substitute MVN for MOV , or MOV for MVN . Be aware of this when reading disassembly listings.

Is Assembly a hex?

Computers don’t use the hexadecimal number system for assembly language. Assembly language, or rather machine code, uses base 256 (typically): instructions are encoded in units of bytes. When displaying machine code, it is customary to use octal or hexadecimal.

How many bits are in the MOV instruction?

12 bits
The mov instruction has only 12 bits to represent the value x.

How do you load a 32-bit constant value to the register ARM?

Load 32-bit immediate values to a register using LDR Rd, =const. The LDR Rd,=const pseudo-instruction generates the most efficient single instruction to load any 32-bit number. You can use this pseudo-instruction to generate constants that are out of range of the MOV and MVN instructions.

Why does the arm MOV instruction use the lowest possible FF?

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.

What is the decimal value of 0xFF in disassembly?

If the tools you’re using to view the disassembly handles the 0..255 as a signed byte, then when it loads it into a larger int type (or register) it will fill all the upper bits with the sign bit of the original value. Or to put it another way, if 0xFF is a signed byte its decimal value is -1.

What is the range of immediate number following MOV instruction?

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 and my textbook, it’s said that range of immediate number following MOV instruction is 0-255. But when I test on my own PC in ADS 1.2 IDE, instruction performs well.

How many bits are in a single ARM instruction?

A single ARM instruction can only encode an immediate constant that can be represented as an 8-bit immediate value, shifted by any even power of two. However, there is also a MVN instruction, which is like MOV but inverts all the bits.