Question

I’m new to at&t syntax. I compiled a test.c file with gcc -S test.c.

part of file in test.s:

 1. .file "test.c"
 2. .local temp
 3. .comm temp,8,4
 4. ...
 5. funtion1:
 6. blah
 7. blah
 8. blah
 9. movl $temp, -8(%ebp)

I know -8(%ebp) is a local var,but not sure what $temp means

How can this be done in nasm?

I have a global temp in the .bss section

can i say:

1. mov eax, [ebp-8]; Does eax contains the memory address of [ebp-8]?
2. mov ebx, temp; Does ebx contain the address of temp?
3. mov [eax], ebx; Does this mean make the local variable point to temp, or that it makes a copy of temp in the local variable?

Answer 1

movl $temp, -8(%ebp) writes the address of your temp into the local variable at ebp-8
This can be done in nasm as mov dword [ebp-8], temp

To answer your other questions:

1. no, eax contains the value of the local variable at [ebp-8]. To load the address, you can use lea eax, [ebp-8]
2. yes
3. makes the local variable a pointer to temp, if eax holds the address of the local variable (see point #1).