How to use gcc as a x86 assembler

[sshahir]

Hi all,

I have developed the following simple assembly program for x86 and called it "Assem_Test1.s":

.MODEL SMALL
.CODE

MOV AH,2
MOV DL,5A
INT 21
INT 20

I have tried the following there commands to generate the .obj file using C compiler as the X86 assembler:


gcc Assem_Test1.s

gcc -assembler Assem_Test1.s

g++ -assembler-with-cpp Assem_Test1.s m_Test1.s


however, I haven't been able to generate the .obj file; instead, the following error messages are thrown:

Assem_Test1.s:1: Error: unknown pseudo-op: `.model'
Assem_Test1.s:2: Error: unknown pseudo-op: `.code'
Assem_Test1.s:4: Error: too many memory references for `mov'
Assem_Test1.s:5: Error: too many memory references for `mov'
Assem_Test1.s:6: Error: suffix or operands invalid for `int'
Assem_Test1.s:7: Error: suffix or operands invalid for `int'
a

I am wondering how I can use the C compiler (either gcc or g++) to generate .obj files. Please let me know if you have any comments or suggestions.

Regards,
sshahir

[amingv]

Hi,

I may be wrong, but I think you can't compile Assembly source with gcc (gcc as the C compiler, I mean), they are different and some keywords just won't fit (for instance, in your source you use int, but int in C serves as an Integer declaration, and in assembler it stands for Interrupt, and transfers control of execution to another proccess). Maybe try this command:

To compile (or better said, assemble):

as Assem_Test1.s -o Assem_Test1.o

To link:

ld Assem_Test1.o -o Assem_Test1

Asuming everything goes right, that should give you an executable named Assem_Test1.

[NathanB]

The example you are attempting to assemble is MASM code for 16-bit DOS. The gcc back-end (g)as assembler expects a different syntax and also expects either 32- or 64-bit code. You should study the material, tutorials, and examples available for Linux ASM programming:

http://linuxassembly.org/

http://members.save-net.com/jko@save-net.com/asm/links.htm