hw2 done

bootloader/Start.S

@@ -12,8 +12,9 @@ wait:
 	b wait
 
 run:
+  // move dtb to x20
 	mov x20, x0
-	adr x0, _start
+	adrp x0, __stack_end
 	mov sp, x0
 
 	adr x0, __text_start
@@ -25,6 +26,7 @@ run:
 	adr x1, __bss_end
 	bl memzero
 
+	// move dtb back to x0
 	mov x0, x20
 	bl main
 	b wait
@@ -36,7 +38,8 @@ relocate:
 	adr x2, __text_end
 	sub x2, x2, x1
 	bl memcpy
-	mov x19, x0
+
+	mov x19, x0 // save return pointer
 
 	// move rodata section
 	ldr x0, =__new_ro_start
@@ -52,5 +55,6 @@ relocate:
 	sub x2, x2, x1
 	bl memcpy
 
+	mov x0, x20
 	br x19
 	b wait