Now I am pretty sure this is a basic question but I couldn't find the answer. How many bits at most can offset be ?
1 Answers
There are six addressing modes supporting this format. The assembler will automatically pick the shortest addressing mode into which the displacement fits. The three relevant of these addressing modes are:
- register indirect, no displacement (displacement must be zero)
- register indirect, 8 bit displacement (displacement must be between −128 and 127)
- register indirect, 32 bit displacement (displacement must be between −2147483648 and 2147483647)
It is not possible to encode a greater displacement than what these addressing modes support. If you need a greater displacement, perform arithmetic to load it. For example, do
mov rax, 123456789abcdef0h
lea rax, [rbx+rax]
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