assembly lea: invalid effective address

Question

I'm getting this kind of error:

beroset-p-637-invalid effective address

Here's a sample code block that contains the error line:

mov eax, 3
mov ebx, 0
lea ecx, [record + count*patient + firstName]          ;this one
int 80h

Here are my variables from the code block above:

patient equ 37
firstName equ 0

count resb 1
record resb patient*5

can't the count variable be used in multiplying with the patient?

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I'm using NASM in x86 Ubuntu 13

Answer 1

You can't multiply by a variable when computing an address. So you would have to multiply count * patient separately and add that in later.