Move screen management code to screen.c and fix cache-related issues

- Screen brightness is now updated as soon as the user selects a brightness option, on all boot environments
- Payloads can now be 1KB bigger
- Some cache-related bugs may have been fixed

loader/linker.ld

@@ -1,7 +1,7 @@
 ENTRY(_start)
 SECTIONS
 {
-    . = 0x24FFFB00;
+    . = 0x24FFFF00;
     .text.start : { *(.text.start) }
     .text : { *(.text) }
     .data : { *(.data) }

loader/source/main.c

@@ -4,7 +4,8 @@ void main(void)
 {
     void *payloadAddress = (void *)0x23F00000;
 
-    memcpy(payloadAddress, (void*)0x24F00000, *(u32 *)0x24FFFB04);
+    memcpy(payloadAddress, (void*)0x24F00000, *(u32 *)0x24FFFF04);
+    cleanInvalidateDCacheAndDMB(); //Ensure that all memory transfers have completed and that the data cache has been flushed 
 
     ((void (*)())payloadAddress)();
 }

loader/source/memory.c

@@ -7,4 +7,9 @@ void memcpy(void *dest, const void *src, u32 size)
 
     for(u32 i = 0; i < size; i++)
         destc[i] = srcc[i];
+}
+
+void cleanInvalidateDCacheAndDMB(void)
+{
+    ((void (*)())0xFFFF0830)(); //Why write our own code when it's well implemented in the unprotected bootROM?
 }

loader/source/memory.h

@@ -2,4 +2,14 @@
 
 #include "types.h"
 
-void memcpy(void *dest, const void *src, u32 size);
+void memcpy(void *dest, const void *src, u32 size);
+
+/***
+    Cleans and invalidates the data cache, then waits for all memory transfers to be finished.
+    This function MUST be called before doing the following:
+        - rebooting
+        - powering down
+        - setting the ARM11 entrypoint to execute a function
+        - jumping to a payload (?)
+***/
+void cleanInvalidateDCacheAndDMB(void);