clean and work on labels

test/label_test.rb

@@ -8,18 +8,25 @@ class TestExtern < MiniTest::Test
     @generator = Asm::Arm::CodeGenerator.new
   end
 
-  def test_generate_small
+  def test_extern
     @generator.instance_eval {
-      ldr r0, "hello world"   #1
-      bl :printf              #2
-    	mov r7, 1               #3
-    	swi 0                   #4  4 instruction x 4 == 16
+      push lr
+      ldr r0, "hello world".to_sym
+      mov r7, 4 #4 is write
+    	swi 0                   
+    	pop pc
+      mov r7, 1   #1 == exit
+    	swi 0
     }
 
+    write(7 , 'label')    
+  end
+  #helper to write the file
+  def write len ,name
     writer = Asm::ObjectWriter.new(Elf::Constants::TARGET_ARM)
     assembly = @generator.assemble
-    assert_equal 20 , assembly.length 
+    assert_equal len * 4 , assembly.length 
     writer.set_text assembly
-    writer.save('small_test.o')    
+    writer.save("#{name}_test.o")    
   end
 end

test/small_program_test.rb

@@ -15,8 +15,7 @@ class TestSmallProg < MiniTest::Test
   def test_generate_small
     @generator.instance_eval {
       mov r0, 5                #1
-      loop_start = label
-      loop_start.set!
+      loop_start = label!
       subs r0, r0, 1          #2
       bne loop_start          #3
     	mov r7, 1               #4
@@ -48,6 +47,6 @@ class TestSmallProg < MiniTest::Test
     assembly = @generator.assemble
     assert_equal len * 4 , assembly.length 
     writer.set_text assembly
-    writer.save('#{name}_test.o')    
+    writer.save("#{name}_test.o")    
   end
 end