Bootable 16bit C program with gcc-ia16

boot.c

void _start(void)
{
	int i, j;
	unsigned short __far *vmem = (void __far*)0xb8000000ul;
	unsigned short c;

	for(i=0; i<25; i++) {
		c = ((i & 0xf) << 8) | '@';
		for(j=0; j<80; j++) {
			*vmem++ = c;
		}
	}

	for(;;);
}

unsigned short bootsig __attribute__((section(".bootsig"))) = 0xaa55;

boot.ld

OUTPUT_FORMAT(binary)
ENTRY(_start)

SECTIONS {
	. = 0x7c00;
	.text : {
		*(.text*);
	}
	.data : {
		*(.rodata*);
		*(.data*);
	}
	.bss ALIGN(4) (NOLOAD): {
		_bss_start = .;
		*(.bss*);
		*(COMMON);
	}
	_bss_size = SIZEOF(.bss);

	. = 0x7c00 + 510;
	.bootsig : { *(.bootsig); }
};

Makefile

bin = boot.img

CC = ia16-elf-gcc
LD = ia16-elf-ld

$(bin): boot.o
	$(LD) -Tboot.ld -o $@ $^

.PHONY: clean
clean:
	rm -f boot.o $(bin)


.PHONY: run
run: $(bin)
	qemu-system-i386 -hda $(bin) -serial file:serial.log

.PHONY: debug
debug: $(bin)
	qemu-system-i386 -hda $(bin) -serial file:serial.log -s -S