Tool Comparison

This is a comparison of various operating system development tools.

x86 Assemblers

	Syntax		Output Format				Instruction Set
	AT&T	Intel	ELF	a.out	COFF	flat	16 bit	32 bit	64 bit
GAS	Yes	Yes[1]	Yes	Yes	Yes	Yes	Yes[2]	Yes	Yes[3]
NASM	No	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes[4]
YASM	Yes	Yes	Yes	No	Yes	Yes	Yes	Yes	Yes
FASM	No	Yes	Yes	No	Yes	Yes	Yes	Yes	Yes
JWASM	No	Yes	Yes	No	Yes	Yes	Yes	Yes	Yes
MASM[5]	No	Yes	No	No	Yes	Yes	Yes	Yes	Yes[6]
Sol_asm	No	Yes[7]	Yes	No	n/a	Yes	Yes	Yes	Yes
AS86	No	Yes	No	No	No	Yes	Yes	Yes	No
llvm-mc	Yes	Yes	Yes	Yes	Yes	No	No	Yes	Yes

• ↑  using the .intel_syntax directive. Several opcodes will still use the AT&T name.
• ↑  While GAS normally writes only "pure" 32-bit i386 code, it has limited support for writing code to run in real mode or in 16-bit protected mode code segments.
• ↑  You have to choose the instruction set at compile time (of the assembler). GAS can not assemble for more than one operating mode at a time, i.e. you would need one GAS for 32bit and one GAS for 64bit if you'd want to mix those two.
• ↑  64-bit support is only available in NASM 2.x.
• ↑  64-bit support is only available in a separate executable, named ml64.
• ↑  Sol_Asm uses its own syntax, which looks like the Intel syntax.

Compilers

	Extensions	Output format
	Inline Assembly	ELF	a.out	flat	PE	COFF	16-bit code segments	32-bit code segments	64-bit code segments
GCC	Yes	Yes	Yes	Yes	Yes	Yes	?	Yes	Yes
Clang	Yes	Yes	Yes	No	Yes	Yes	No	Yes	Yes
msvc	Yes	No	No	No[8]	Yes	Yes	Version 4.X	Yes	Yes
icl	Yes	No	No	No	Yes	Yes	No	Yes	Yes
Watcom	Yes	No	No	No	Yes	Yes	Yes	Yes	Yes
Smaller C	Yes	Yes	Yes	Yes	Yes	No	Yes (incl. huge & unreal mode(l)s)[9]	Yes	No

• ↑  Visual Studio can emit .COM files.
• ↑  Smaller C wasn't really designed to properly support 16-bit and 64-bit CPUs.

Linkers

Name	Input					Output					Flat Binary Images	Set Code Address	Library Support	Supports Debug Info	32bit Code
	OMF/ OBJ	Win32/ COFF	ELF	A.OUT	Others	Win32/ PE	Win32/ DLL	ELF	A.OUT	Others
JLoc	Yes					No	No	No	No	DOS/COM	Yes	Yes	No	OMF/OBJ	Yes
ALink	Yes	Yes	No	No	DJGPP/COFF	Yes	Yes	No	No	DOS/COM DOS/EXE	No	Yes	Yes	No	Yes
LD	Yes	Yes	Yes	Yes	DJGPP/COFF OMF/COFF	Yes	Yes	Yes	Yes	various	Yes	Yes	Yes	ECOFF DWARF STABS	Yes
TLink	Yes	Yes	No	No		Yes	Yes	No	No	DOS/EXE DOS/COM	No	Yes	Yes	OMF/OBJ	Yes
Link	Yes	Yes	No	No		Yes	Yes	No	No	DOS/EXE DOS/COM LE	No	Yes	Yes	CODEVIEW DWARF	Yes
VAL	Yes					No	No	No	No	DOS/EXE	No	No	No	Yes	No
WLink	Yes	Yes	Yes	No		Yes	Yes	Yes	No	DOS/EXE DOS/COM LE Pharlap Novell_NLM Causeway QNX	Yes	Yes	Yes	WATCOM CODEVIEW DWARF	Yes
smlrl	No	No	Yes	No		Yes	No	Yes	Yes	DOS/COM DOS/EXE MACH-O	Yes	Yes	Yes	No	Yes
LLD		Yes	Yes										Yes		Yes