First program to return to polmon

Makefile

@@ -53,15 +53,19 @@ wozmon.bin: wozmon.elf
 paracli.elf: LDFLAGS += -T doscom.ld
 paracli.elf: paracli.s paracomm.o
 
-mushroom.elf: LDFLAGS += -T doscom.ld
-mushroom.elf: mushroom.s paracomm.o
+dos-programs = mushroom.elf hello.elf
+$(dos-programs): LDFLAGS += -T doscom.ld
 
-polos.img: fat12boot.bin polmon.com polio.com mushroom.com
+mushroom.elf: mushroom.s
+hello.elf: hello.o stdlib.o crt0.s
+
+polos.img: fat12boot.bin polmon.com polio.com mushroom.com hello.com
 	dd if=/dev/zero of=$@ bs=512 count=720
 	mformat -i $@ -t 40 -h 2 -s 9
 	mcopy -i $@ polio.com ::/
 	mcopy -i $@ polmon.com ::/
 	mcopy -i $@ mushroom.com ::/
+	mcopy -i $@ hello.com ::/
 	dd if=fat12boot.bin of=$@ conv=notrunc
 
 .PHONY: clean

crt0.s

@@ -0,0 +1,8 @@
+    .arch i8086,jumps
+    .code16
+    .intel_syntax noprefix
+
+    .section .init
+    .global _start
+_start:
+    jmp main

hello.c

@@ -0,0 +1,5 @@
+#include <stdio.h>
+
+int main() {
+    puts("Hello, world!\r\n");
+}