错误：FASM x86组件中的值超出范围

Question

why am I getting error: value out of range. in the following code?

mov eax,dword ptr "abcdlol$"

I want to put the address of "abcdlol" into eax register but looks like isn't this value that FASM is copying into eax .

An example In C code: int *p="lol";

How to fix this? Is this an assembler's limitation?

Answer 1

It FASM syntax it should be:

mov eax,my_string
my_string db "abcdlol$"

You can also use lea :

lea eax,[my_string]
my_string db "abcdlol$"

Whether to use ASCIIZ string (terminated with 0) or some other terminator depends on what you are going to do with the string. It seems that you are using $ as string terminator, that is used by DOS print string function. Check that $ is the right string terminator for the OS API functions you are going to use (if any). For example printf requires zero-terminated (ASCIIZ) strings.

See FASM HelloWorld .exe program see an example of FASM syntax.

dword ptr and the like are needed only when addressing the memory. mov eax,abcdlol is just a mov eax,immed32 . Processor does not worry whether you're you're going to use the value stored in eax as a number or as a pointer.

Answer 2

This should work:

mystring  db  "abcdlol", 0
mov eax,mystring

Answer 3

Back to basics:

EAX can store only 4 bytes. "abcdlol$" is 8 bytes. So instead of putting the value directly, you should put the address of it into EAX as suggested by other posters. But if you insist, use two registers:

mov eax,"abcd" ;4 bytes
mov ebx,"lol$" ;4 bytes

or in 64-bit,

mov rax,"abcdlol$"

You should tell the difference between passing immediate values and passing addresses to the registers.