New Romheader format (#1628)

3 files changed, 196 insertions, 17 deletions

diff --git a/Makefile b/Makefile
index 113be97f9..be9071dee 100644
--- a/Makefile
+++ b/Makefile
@@ -417,7 +417,7 @@ $(BUILD_DIR)/src/boot/z_std_dma.o: $(BUILD_DIR)/dmadata_table_spec.h
 $(BUILD_DIR)/src/dmadata/dmadata.o: $(BUILD_DIR)/dmadata_table_spec.h
 
 $(BUILD_DIR)/asm/%.o: asm/%.s
-	$(AS) $(ASFLAGS) $< -o $@
+	$(CPP) $(CPPFLAGS) -Iinclude $< | $(AS) $(ASFLAGS) -o $@
 
 $(BUILD_DIR)/assets/%.o: assets/%.c
 	$(CC) -c $(CFLAGS) $(MIPS_VERSION) $(OPTFLAGS) -o $@ $<
diff --git a/include/rom_header.h b/include/rom_header.h
new file mode 100644
index 000000000..1069ae86f
--- /dev/null
+++ b/include/rom_header.h
@@ -0,0 +1,145 @@
+#ifndef ROM_HEADER_H
+#define ROM_HEADER_H
+
+/* Storage medium IDs, used internally in MEDIUM below */
+
+#define STORAGE_MEDIUM_CARTRIDGE            "N"
+#define STORAGE_MEDIUM_CARTRIDGE_EXPANDABLE "C"
+#define STORAGE_MEDIUM_DISK                 "D"
+#define STORAGE_MEDIUM_DISK_EXPANSION       "E"
+
+/* Region IDs, used internally in REGION below */
+
+#define REGION_CODE_ALL      "A"
+#define REGION_CODE_JP       "J"
+#define REGION_CODE_US       "E"
+#define REGION_CODE_PAL      "P"
+#define REGION_CODE_GATEWAY  "G"
+#define REGION_CODE_LODGENET "L"
+
+/**
+ * Magic value to determine if the ROM is byteswapped.
+ *
+ * This is not totally reliable since the PI Domain 1 Latency could also hold this value, however generally it can be
+ * assumed that this is not the case.
+ */
+#define ENDIAN_IDENTIFIER \
+    .byte 0x80
+
+/**
+ * Configures the timings for PI Domain 1. This determines how fast the PI hardware will read from the ROM. IPL2 reads
+ * this configuration using the slowest possible configuration before switching to the provided configuration.
+ */
+#define PI_DOMAIN_1_CFG(lat, pwd, pgs, rls)   \
+    .byte (((rls) & 3) << 4) | ((pgs) & 0xF); \
+    .byte (pwd) & 0xFF;                       \
+    .byte (lat) & 0xFF
+
+/**
+ * Some older libultra versions use this field to set osClockRate. It does not have any other meaningful effect, the
+ * clock rate of physical units does not actually change to match this value.
+ */
+#define SYSTEM_CLOCK_RATE_SETTING(num) \
+    .word (num)
+
+/**
+ * Indicates the entrypoint address of the program that IPL3 will load the boot segment to and execute.
+ * This should be >= 0x80000400.
+ */
+#define ENTRYPOINT(sym) \
+    .word (sym)
+
+/**
+ * Indicates the hardware revision the program is designed for (hw_major, hw_minor)
+ * and what libultra version (os_ver) it uses.
+ *
+ * The hardware revision for a retail N64 is (2,0).
+ * The libultra version may be a single letter, without quotes.
+ */
+#define LIBULTRA_VERSION(hw_major, hw_minor, os_ver)   \
+    .half 0;                                           \
+    .byte (hw_major) * 10 + (hw_minor);                \
+    _os_ver_start = .;                                 \
+    .ascii #os_ver ;                                   \
+    .if (. - _os_ver_start) != 1;                      \
+        .error "OS version should be just one letter"; \
+    .endif
+
+/**
+ * Leaves space to insert the ROM Checksum value. IPL3 computes a checksum over ROM data in the range 0x1000 to 0x101000
+ * and compares it to this value, if the results differ it will refuse to boot the program.
+ *
+ * This macro just writes 8 bytes of 0. The correct checksum value is filled in after the full ROM image is available to
+ * compute the checksum with.
+ */
+#define CHECKSUM() \
+    .word 0, 0
+
+/**
+ * For unused header space. Fills num bytes with 0.
+ */
+#define PADDING(num) \
+    .fill (num)
+
+/**
+ * Defines the ROM name. This should be a string that is at most 20 characters long, a null terminator is not required.
+ * If a name is less than 20 characters, the remaining space will be padded with spaces.
+ */
+#define ROM_NAME(name)                                             \
+    _name_start = .;                                               \
+    .ascii name;                                                   \
+    .if (. - _name_start) > 20;                                    \
+        .error "ROM name too long, must be at most 20 characters"; \
+    .endif;                                                        \
+    .if (. - _name_start) < 20;                                    \
+        .fill 20 - (. - _name_start), 1, 0x20;                     \
+    .endif
+
+/**
+ * Identifies the storage medium the program intends to use.
+ *
+ * Should be one of:
+ *  - CARTRIDGE
+ *  - CARTRIDGE_EXPANDABLE
+ *  - DISK
+ *  - DISK_EXPANSION
+ */
+#define MEDIUM(type) \
+    .ascii STORAGE_MEDIUM_##type
+
+/**
+ * Two-letter game identifier. Should be wrapped in quotes.
+ */
+#define GAME_ID(id)                             \
+    _game_id_start = .;                         \
+    .ascii id ;                                 \
+    .if (. - _game_id_start) != 2;              \
+        .error "Game ID should be two letters"; \
+    .endif
+
+/**
+ * Identifies the region the game is made for.
+ *
+ * Should be one of:
+ *  - ALL
+ *  - JP
+ *  - US
+ *  - PAL
+ *  - GATEWAY
+ *  - LODGENET
+ *
+ * Note: Often flashcarts and emulators will read this value to determine whether to act as an NTSC or PAL system and
+ *       will adjust the VI timings appropriately, which may be used to determine target FPS.
+ *       This can lead to glitchy video output on hardware if the program configures a video mode other than the native
+ *       video mode for the hardware version.
+ */
+#define REGION(name) \
+    .ascii REGION_CODE_##name
+
+/**
+ * Identifies the game revision number. Can be between 0 and 255.
+ */
+#define GAME_REVISION(num) \
+    .byte (num)
+
+#endif
diff --git a/tools/disasm/disasm.py b/tools/disasm/disasm.py
index 4a91303bb..3ab718c31 100755
--- a/tools/disasm/disasm.py
+++ b/tools/disasm/disasm.py
@@ -1756,16 +1756,48 @@ def get_overlay_sections(vram, overlay):
         [bss_end_vram, bss_end_vram, "reloc", None, overlay[header_loc:], None],
     ]
 
+def get_storage_medium(id):
+    if id == 'N':
+        return "CARTRIDGE"
+    elif id == 'C':
+        return "CARTRIDGE_EXPANDABLE"
+    elif id == 'D':
+        return "DISK"
+    elif id == 'E':
+        return "DISK_EXPANSION"
+    else:
+        return "UNKNOWN"
+
+def get_region(id):
+    if id == 'A':
+        return "ALL"
+    elif id == 'J':
+        return "JP"
+    elif id == 'E':
+        return "US"
+    elif id == 'P':
+        return "PAL"
+    elif id == 'G':
+        return "GATEWAY"
+    elif id == 'L':
+        return "LODGENET"
+    else:
+        return "UNKNOWN"
 
 def disassemble_makerom(section):
     os.makedirs(f"{ASM_OUT}/makerom/", exist_ok=True)
 
     if section[2] == "rom_header":
         (
+            endian,
             pi_dom1_reg,
+            pi_dom1_pwd,
+            pi_dom1_lat,
             clockrate,
             entrypoint,
-            revision,
+            pad_ver,
+            hw_ver,
+            os_ver,
             chksum1,
             chksum2,
             pad1,
@@ -1776,26 +1808,28 @@ def disassemble_makerom(section):
             cart_id,
             region,
             version,
-        ) = struct.unpack(">IIIIIIII20sII2s1sB", section[4])
+        ) = struct.unpack(">BBBBIIHBBIIII20sII2s1sB", section[4])
+
 
         out = f"""/*
  * The Legend of Zelda: Majora's Mask ROM header
  */
 
-.word  0x{pi_dom1_reg:08X}             /* PI BSD Domain 1 register */
-.word  0x{clockrate:08X}             /* Clockrate setting */
-.word  0x{entrypoint:08X}             /* Entrypoint function (`entrypoint`) */
-.word  0x{revision:08X}             /* Revision */
-.word  0x{chksum1:08X}             /* Checksum 1 */
-.word  0x{chksum2:08X}             /* Checksum 2 */
-.word  0x{pad1:08X}             /* Unknown */
-.word  0x{pad2:08X}             /* Unknown */
-.ascii "{rom_name.decode('ascii')}" /* Internal ROM name */
-.word  0x{pad3:08X}             /* Unknown */
-.word  0x{cart:08X}             /* Cartridge */
-.ascii "{cart_id.decode('ascii')}"                   /* Cartridge ID */
-.ascii "{region.decode('ascii')}"                    /* Region */
-.byte  0x{version:02X}                   /* Version */
+#include "rom_header.h"
+
+/* 0x00 */ ENDIAN_IDENTIFIER
+/* 0x01 */ PI_DOMAIN_1_CFG({pi_dom1_lat}, {pi_dom1_pwd}, {pi_dom1_reg & 0xF}, {(pi_dom1_reg >> 4) & 3})
+/* 0x04 */ SYSTEM_CLOCK_RATE_SETTING(0x{clockrate:X})
+/* 0x08 */ ENTRYPOINT(0x{entrypoint:08X})
+/* 0x0C */ LIBULTRA_VERSION({hw_ver // 10}, {hw_ver % 10}, {chr(os_ver)})
+/* 0x10 */ CHECKSUM()
+/* 0x18 */ PADDING(8)
+/* 0x20 */ ROM_NAME("{rom_name.decode('ascii').rstrip()}")
+/* 0x34 */ PADDING(7)
+/* 0x3B */ MEDIUM({get_storage_medium(chr(cart))})
+/* 0x3C */ GAME_ID("{cart_id.decode('ascii')}")
+/* 0x3E */ REGION({get_region(region.decode('ascii'))})
+/* 0x3F */ GAME_REVISION({version})
 """
         with open(ASM_OUT + "/makerom/rom_header.s", "w") as outfile:
             outfile.write(out)