Move the system heap and the framebuffers to their own segments (#1488)

* make segments for the systemheap and the framebuffers

* define in the makefile

* undefined syms

* Make segments for the pre boot buffers too

* Update spec

Co-authored-by: Parker <20159000+jpburnett@users.noreply.github.com>

* review

* Update spec

Co-authored-by: Parker <20159000+jpburnett@users.noreply.github.com>

* Update Makefile

Co-authored-by: Dragorn421 <Dragorn421@users.noreply.github.com>

* comments

* comment

* move comment about the hardcoded address to buffers.h

* rewrite SYSTEM_HEAP_END_ADDR in terms of other symbols

* Use `ALIGNED` on all the buffers

* Rename SYSTEM_HEAP_END_ADDR to FRAMEBUFFERS_START_ADDR

* Put ALIGNED at the right like the rest of the codebase

* merge

* gLoBuffer

* gHiBuffer

* Add a static assert to ensure the address of gHiBuffer haven't shifted without the user noticing

* smol include cleanup

---------

Co-authored-by: Parker <20159000+jpburnett@users.noreply.github.com>
Co-authored-by: Dragorn421 <Dragorn421@users.noreply.github.com>

4 files changed, 75 insertions, 8 deletions

diff --git a/include/buffers.h b/include/buffers.h
index 72615a717..ed8b2152c 100644
--- a/include/buffers.h
+++ b/include/buffers.h
@@ -1,9 +1,24 @@
 #ifndef BUFFERS_H
 #define BUFFERS_H
 
-#include "z64.h"
+#include "libc/assert.h"
+#include "gfx.h"
 #include "macros.h"
 #include "stack.h"
+#include "z64save.h"
+
+typedef union {
+    u16 framebufferHiRes[HIRES_BUFFER_HEIGHT][HIRES_BUFFER_WIDTH] ALIGNED(64);
+    struct {
+        u16 framebuffer[SCREEN_HEIGHT][SCREEN_WIDTH] ALIGNED(64);
+        u8 skyboxBuffer[0x5A360] ALIGNED(16);
+    };
+} BufferLow;
+
+// Equivalent to gLoBuffer.framebufferHiRes, but a different symbol is required to match
+extern u16 gFramebufferHiRes1[HIRES_BUFFER_WIDTH][HIRES_BUFFER_HEIGHT];
+
+extern BufferLow gLoBuffer;
 
 
 extern u8 gGfxSPTaskYieldBuffer[OS_YIELD_DATA_SIZE];
@@ -12,9 +27,40 @@ extern GfxPool gGfxPools[2];
 extern u8 gAudioHeap[0x138000];
 extern u8 gSystemHeap[];
 
-extern u8 gPictoPhotoI8[PICTO_PHOTO_SIZE];
-extern u8 D_80784600[0x56200];
-extern u16 gFramebuffer0[SCREEN_HEIGHT][SCREEN_WIDTH];
+
+typedef union {
+    u16 framebufferHiRes[HIRES_BUFFER_HEIGHT][HIRES_BUFFER_WIDTH] ALIGNED(64);
+    struct {
+        u8 pictoPhotoI8[PICTO_PHOTO_SIZE] ALIGNED(64);
+        u8 D_80784600[0x56200] ALIGNED(64);
+        u16 framebuffer[SCREEN_HEIGHT][SCREEN_WIDTH] ALIGNED(64);
+    };
+} BufferHigh;
+
+// Equivalent to gHiBuffer.framebufferHiRes, but a different symbol is required to match
+extern u16 gFramebufferHiRes0[HIRES_BUFFER_HEIGHT][HIRES_BUFFER_WIDTH];
+
+extern BufferHigh gHiBuffer;
+
+#ifndef FRAMEBUFFERS_START_ADDR
+/**
+ * The `framebuffers` segment is located at a fixed location in RAM and has a
+ * fixed size.
+ * Those framebuffers are placed at the end of the RAM space.
+ * This address is calculated by doing `0x80800000 - (size of framebuffers)`,
+ * where 0x80800000 is the end of the Expansion Pak address range.
+ * In the vanilla game this value expands to `0x80780000`.
+ *
+ * Since the start of the `framebuffers` segment is the end of the not-fixed
+ * available RAM, then the `system_heap` covers all the remaining RAM that is
+ * not used by the non-relocatable code/data (i.e. `boot`, `code`, and other
+ * buffers) up to the start of the `framebuffers` segmemt.
+ * @see `Main`
+ */
+#define FRAMEBUFFERS_START_ADDR (PHYS_TO_K0(0x800000) - sizeof(BufferHigh))
+
+static_assert(FRAMEBUFFERS_START_ADDR == 0x80780000, "The expected address of gHiBuffer shifted. Please update said address in buffers.h and in the spec file.");
+#endif
 
 
 #endif
diff --git a/include/libc/assert.h b/include/libc/assert.h
new file mode 100644
index 000000000..7fee0a815
--- /dev/null
+++ b/include/libc/assert.h
@@ -0,0 +1,21 @@
+#ifndef LIBC_ASSERT_H
+#define LIBC_ASSERT_H
+
+// Static/compile-time assertions
+
+#if (__STDC_VERSION__ >= 202311L)
+// static_assert is a keyword in C23, do not define it
+#elif (__STDC_VERSION__ >= 201112L)
+# define static_assert(cond, msg) _Static_assert(cond, msg)
+#else
+# ifndef GLUE
+#  define GLUE(a, b) a##b
+# endif
+# ifndef GLUE2
+#  define GLUE2(a, b) GLUE(a, b)
+# endif
+
+# define static_assert(cond, msg) typedef char GLUE2(static_assertion_failed, __LINE__)[(cond) ? 1 : -1]
+#endif
+
+#endif
diff --git a/include/segment_symbols.h b/include/segment_symbols.h
index 4d5824138..c49c08026 100644
--- a/include/segment_symbols.h
+++ b/include/segment_symbols.h
@@ -39,6 +39,8 @@
 #define ROM_FILE_UNSET \
     { 0 }
 
+DECLARE_SEGMENT(framebuffer_lo)
+
 DECLARE_SEGMENT(boot)
 DECLARE_ROM_SEGMENT(boot)
 
@@ -78,6 +80,8 @@ DECLARE_SEGMENT(code)
 DECLARE_ROM_SEGMENT(code)
 DECLARE_BSS_SEGMENT(code)
 
+DECLARE_SEGMENT(system_heap)
+
 DECLARE_OVERLAY_SEGMENT(kaleido_scope)
 DECLARE_OVERLAY_SEGMENT(player_actor)
 
diff --git a/include/variables.h b/include/variables.h
index 638a8656c..dce2df663 100644
--- a/include/variables.h
+++ b/include/variables.h
@@ -5,10 +5,6 @@
 #include "segment_symbols.h"
 #include "macros.h"
 
-// pre-boot variables
-extern u16 gFramebuffer1[SCREEN_HEIGHT][SCREEN_WIDTH]; // at 0x80000500
-extern u8 D_80025D00[];
-
 // data
 extern size_t gDmaMgrDmaBuffSize;
 extern vs32 gIrqMgrResetStatus;