add itoa and build "system"

build.sh

@@ -0,0 +1,30 @@
+build () {
+    FILE="$1"
+    PROGRAM_NAME=$(basename "$FILE" ".asm")
+
+    if [ ! -f "$FILE" ]; then
+        echo "$PROGRAM_NAME not found"
+        return
+    fi
+
+    echo "Building $PROGRAM_NAME"
+    nasm -g -F dwarf -f elf64 "$FILE" -o "./target/$PROGRAM_NAME.o" && ld.lld "./target/$PROGRAM_NAME.o" -o "./target/$PROGRAM_NAME"
+}
+
+
+if [ "$1" = "--clean" ]; then
+    rm -r target
+    exit
+fi
+
+if [ ! -d ./target ]; then
+  mkdir ./target
+fi
+
+if [ "$#" -eq 0 ]; then
+  for FILE in ./src/*.asm ; do
+    build "$FILE"
+  done
+else
+  build "src/$1.asm"
+fi