Assembly in DragonFly

Karthik Subramanian karthik301176 at
Mon Mar 13 23:25:09 PST 2006

Hi Folks,
After installing DragonFly on a spare box at work, I was trying out asimple "Hello World" in assembly, and found that one needed to do alittle more than "as -o hello.o hello.s; ld -o hello hello.o" to getit to work; here's what I did:
1. Wrote a "Hello World" in assembly:
============ hello.s =====================================.section .data
helloworld: .ascii "Hello, World\n"len      : .long . - helloworld
. section .text
. globl _start
syscall:    int $0x80    ret
_start:    pushl $len    pushl $helloworld    pushl $1    movl  $4, %eax    call  syscall    add   $12, %esp # clean up stack
    pushl $0    movl  $1, %eax    call syscall==========================================================
2. Ran "as -o hello.o hello.s; ld -o hello hello.o; ./hello", and sawthis on the console:
ELF binary type "0" not known.Abort trap
3. Running "file hello" produced this output:
hello: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV),statically linked,not stripped
4. Scratched head a little. Inspired by the lead of [1], wrote a small"Hello, World" in C, ran objdump on the executable. Et Voila, it lookedlike I had found what was required:
Contents of section .note.ABI-tag: 8048110 0a000000 04000000 01000000 44726167  ............Drag 8048120 6f6e466c 79000000 d6fb0100                        onFly.......
5. I then added the following to the original hello.s:
=============================================================.section .note.ABI-tag, "a"    .long 0xA    .long 0x4    .long 0x1    .string "DragonFly"    .long 0x1fbd6==============================================================
And it works!
This probably isn't of much use to anybody except for crazy guys likeme who like to code in assembly once in a while - but I thought I'dpost it here anyway.
1., and

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