From 37dbb99f509305dbf76ec7a4abe8d2c198595aee Mon Sep 17 00:00:00 2001
From: "brice.boisson" <brice.boisson@epita.fr>
Date: Wed, 11 Oct 2023 09:38:29 +0900
Subject: [PATCH] Add: userland hello world code

---
 Makefile          |  4 ++--
 Makefile.common   |  1 +
 app/hello_world.c | 10 ++++++++++
 3 files changed, 13 insertions(+), 2 deletions(-)
 create mode 100644 app/hello_world.c

diff --git a/Makefile b/Makefile
index b87473f..252c1bb 100644
--- a/Makefile
+++ b/Makefile
@@ -11,8 +11,8 @@ install:
 
 bin:
 	$(MAKE) -C $(LIB)
-	gcc -c test.c -Ilibk -Llibk -lk -m32
-	ld -m elf_i386 -Ttext=0x6000000 --entry=main test.o -L./libk/ -lk
+	gcc -c ./app/$(APP).c -Ilibk -Llibk -lk -m32
+	ld -m elf_i386 -Ttext=0x6000000 --entry=main ./$(APP).o -L./libk/ -lk
 	objcopy --input binary --output elf32-i386 --binary-architecture i386 --rename-section .data=.rodata,CONTENTS,ALLOC,LOAD,READONLY,DATA a.out myfile.o
 	cp myfile.o $(SOURCEDIR)/myfile.o
 
diff --git a/Makefile.common b/Makefile.common
index 92ed0b0..561c3fb 100644
--- a/Makefile.common
+++ b/Makefile.common
@@ -5,3 +5,4 @@ GRUBDIR = iso
 SOURCEDIR = src
 TARGET = kernel
 LIB=libk
+APP=hello_world
diff --git a/app/hello_world.c b/app/hello_world.c
new file mode 100644
index 0000000..6c98f9c
--- /dev/null
+++ b/app/hello_world.c
@@ -0,0 +1,10 @@
+#include <syscall.h>
+
+static char s[] = "Hello from userland!\n";
+
+int main(void)
+{
+    write(1, s, 21);
+    while (1);
+    return 0;
+}