The following example does not have a class specifying the brush to use. This is extracted from the mode-line. This line also specifies other options, in this case the tab-width.
# -*- mode: asm; tab-width: 4; -*- .text .global _start _start: # ssize_t sys_write(unsigned int fd, const char __user * buf, size_t count) movl $len, %edx # size_t count movl $msg, %ecx # const char __user * buf movl $1, %ebx # unsigned int fd movl $4, %eax # system call number (sys_write) int $0x80 # call kernel # void _exit(int status); movl $0, %ebx # int status movl $1, %eax # system call number (sys_exit) int $0x80 # call kernel .data # section declaration msg: .ascii "Hello, world!\n" len = . - msg