how to do add operation in ARM
Assembler instruction Effect of the assembler instruction
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add r0, r1, r2 r0 = r1 + r2
add r0, r0, r0 r0 = r0 + r0 = 2×r0
add r0, r0, #1 r0 = r0 + 1
sub r0, r1, r2 r0 = r1 - r2
rsb r0, r1, r2 r0 = r2 - r1
rsb r0, r0, #0 r0 = 0 - r1 = -r0 (negation !!)
mul r0, r1, r2 r0 = r1 * r2
mul r1, r0, r0 r1 = r0 * r0 = r02