Decompile graph.c (#274)

* Decompiled, 1 non-matching, add some bss reordering helpers

* Document stuff

* Review suggestions

* graphutil.c -> graphalloc.c

* Try to fix fault callback warnings

* Remove extra comments in GfxMasterList

* char pad -> u32 pad

Co-authored-by: Derek Hensley <hensley.derek58@gmail.com>

* Fix gameState

Co-authored-by: engineer124 <47598039+engineer124@users.noreply.github.com>

* Other suggestions

Co-authored-by: Derek Hensley <hensley.derek58@gmail.com>
Co-authored-by: engineer124 <47598039+engineer124@users.noreply.github.com>

src/code/graphalloc.c

@@ -0,0 +1,29 @@
+#include "global.h"
+
+Gfx* Graph_GfxPlusOne(Gfx* gfx) {
+    return &gfx[1];
+}
+
+Gfx* Graph_BranchDlist(Gfx* gfx, Gfx* dst) {
+    gSPBranchList(gfx, dst);
+    return dst;
+}
+
+/**
+ * Allocates a structure of `size` into the display list buffer`gfx`,
+ * returning a pointer to the start of the buffer.
+ * Since the alloc may not itself be display list commands, a BranchList
+ * command is used to step over this region.
+ */
+void* Graph_DlistAlloc(Gfx** gfx, size_t size) {
+    u8* start;
+    Gfx* end;
+
+    size = ALIGN8(size);
+    start = (u8*)&(*gfx)[1];
+    end = (Gfx*)(start + size);
+    gSPBranchList(*gfx, end);
+
+    *gfx = end;
+    return start;
+}