You can place it in "Compiler settings -> Other options".
The assembly code will be in the *.o-files in this case (because C::B uses the -o-option), and it will be done for all processed files.
Or you can change the build-command for your file in the files properties (tab "advanced"):
check "Use custom command ..." and add $compiler $options $includes -S -c $file
$compiler $options $includes -c $file -o $object
The example is for c++-files.
I double the command, so the file will be processed twice, one-time only the assembly is generated, the second time I do the normal processing, otherwise your build will be broken due to missing object-file or because an old object-file is taken (if it exists).
And this is what mine first assembly file contains
.file "G2.c"
.text
.def _printf; .scl 3; .type 32; .endef
_printf:
pushl %ebp
movl %esp, %ebp
pushl %ebx
subl $36, %esp
leal 12(%ebp), %eax
movl %eax, -12(%ebp)
movl -12(%ebp), %eax
movl %eax, 4(%esp)
movl 8(%ebp), %eax
movl %eax, (%esp)
call ___mingw_vprintf
movl %eax, %ebx
movl %ebx, %eax
addl $36, %esp
popl %ebx
popl %ebp
ret
.def ___main; .scl 2; .type 32; .endef
.section .rdata,"dr"
LC0:
.ascii "\12\12Hi there\12\12\0"
.text
.globl _main
.def _main; .scl 2; .type 32; .endef
_main:
pushl %ebp
movl %esp, %ebp
andl $-16, %esp
subl $16, %esp
call ___main
movl $LC0, (%esp)
call _printf
leave
ret
.def ___mingw_vprintf; .scl 2; .type 32; .endef