[Nasm-devel] 2 Problems: (Strange Linking Problem) && (Strange Syntatx Error)

[Matthias-Christian O. <mat...@ti...>]

Hi!
I've 2 Problems with nasm:

1: *Strage Linking Problem*

I have this code:

SECTION .DATA
        hello:     db 'Hello world!',10
        helloLen:  equ $-hello

SECTION .TEXT
        GLOBAL main

main:
        ; Write 'Hello world!' to the screen
        mov eax,4            ; 'write' system call
        mov ebx,1            ; file descriptor 1 = screen
        mov ecx,hello        ; string to write
        mov edx,helloLen     ; length of string to write
        int 80h              ; call the kernel

        ; Terminate program
        mov eax,1            ; 'exit' system call
        mov ebx,0            ; exit with error code 0
        int 80h              ; call the kernel

If try to assemble, link (by using ld) and run it, I only get a 
segementation fault (I have to rename main to _start):

nasm -f elf hello.asm
ld -s -o hello hello.o
./hello
segementation fault

If I try to link it with the gcc (_start -> main), everything works fine.

What's wrong? Why doesn't it work?

2: *Strange Syntax Error*

I have this code (I know that it will only work in the priviledged mode, 
but it should assemble cleanly (?)):

global sys_core_in

sys_core_in:
        push    ebp
        push    dx
        mov     ebp,esp
        in      edx,[ebp+4]
        mov     eax,dx
        pop     dx
        pop     ebp
        ret

global sys_core_out

sys_core_out:
        push    ebp
        mov     ebp,esp
        out     [ebp+4],[ebp+8]
        pop     ebp
        ret

If I try to assemble it I get this:

io.s:7: error: invalid combination of opcode and operands
io.s:8: error: invalid combination of opcode and operands
io.s:18: error: invalid combination of opcode and operands

What's wrong with the syntax?

Thanks
Matthias-Chritian Ott