Add Mapper 002 (UxROM); more refactoring for redundant mapper init

src/cart.c

@@ -53,26 +53,6 @@ int nes_cart_load_mem(void* data, int size, nes* sys) {
     }
 
     if (0 == status) {
-        // PPU Bank 0 - 7: Default pattern tables
-        for (int page = 0; page < 8; ++page) {
-            mem->ppu.bank[page] = chr_page(&mem->ppu, page);
-        }
-
-        // PPU Bank 8 - 11: Mirrored VRAM
-        nes_ppu_set_mirroring(
-                &mem->ppu, hdr->flags_6 & ines_Flag_Vert_Mirror
-            );
-
-        // PPU Bank 12 - 15: Unused & Palette
-        for (int page = 12; page < 16; ++page) {
-            mem->ppu.bank[page] = mem->ppu.pal_bank;
-        }
-
-        // Map the SRAM bank to battery-backed SRAM if present
-        if (hdr->flags_6 & ines_Flag_Battery) {
-            mem->sram_bank = mem->sram;
-        }
-
         int i_mapper = (hdr->flags_7 & ines_Mapper_Nibble_Hi) |
                 ((hdr->flags_6 & ines_Mapper_Nibble_Lo) >> 4);
         const nes_Mapper *mapper = nes_mappers[i_mapper];
@@ -80,9 +60,48 @@ int nes_cart_load_mem(void* data, int size, nes* sys) {
             LOGE("Mapper %d not supported", i_mapper);
             status = -1;
         } else {
-            LOGI("Mapper %d", i_mapper);
+            // Set up CHR RAM if used
+            if (hdr->chr_size_lsb <= 0) {
+                int chr_size = mapper->max_chr_banks *
+                               NES_CHR_ROM_PAGE_SIZE;
+                mem->ppu.chr_ram = calloc(1, chr_size);
+                LOGI("CHR RAM: %d kB", chr_size / 1024);
+                mem->ppu.chr = mem->ppu.chr_ram;
+                mem->ppu.n_chr_banks = chr_size /
+                                       NES_CHR_ROM_PAGE_SIZE;
+            }
+
+            LOGI("Mapper %d: %s", i_mapper, mapper->name);
             mem->mapper = *mapper;
-            status = mem->mapper.init(&mem->mapper, hdr, mem);
+            mem->mapper.data = calloc(1, mapper->data_size);
+            if (NULL == mem->mapper.data) {
+                LOGE("Failed to allocate mapper data");
+                status = -1;
+            } else {
+                // PPU Bank 0 - 7: Default pattern tables
+                for (int page = 0; page < 8; ++page) {
+                    mem->ppu.bank[page] = chr_page(&mem->ppu, page);
+                }
+
+                // PPU Bank 8 - 11: Mirrored VRAM
+                nes_ppu_set_mirroring(
+                        &mem->ppu, hdr->flags_6 & ines_Flag_Vert_Mirror
+                    );
+
+                // PPU Bank 12 - 15: Unused & Palette
+                for (int page = 12; page < 16; ++page) {
+                    mem->ppu.bank[page] = mem->ppu.pal_bank;
+                }
+
+                // Map the SRAM bank to battery-backed SRAM if present
+                if (hdr->flags_6 & ines_Flag_Battery) {
+                    mem->sram_bank = mem->sram;
+                }
+
+                status = mem->mapper.init(&mem->mapper,
+                                          hdr, mem);
+            }
+            // TODO: Deallocate mapper data when we're done
         }
     }
 

src/map/map000.c

@@ -22,5 +22,6 @@ static int map000_init(nes_Mapper* map, const ines_Header* hdr,
 const nes_Mapper map000 = {
     .name           = "NROM",
     .max_chr_banks  = 8,
+    .data_size      = 0,
     .init           = map000_init,
 };

src/map/map001.c

@@ -1,5 +1,3 @@
-#include <stdlib.h>
-
 #include "memory.h"
 
 //#define DEBUG "MMC1"
@@ -90,16 +88,8 @@ static void map001_reset(nes_Mapper* map, nes_Memory* mem) {
 
 static int map001_init(nes_Mapper* map, const ines_Header* hdr,
                        nes_Memory* mem) {
-    int status = -1;
-
-    map->data = calloc(1, sizeof(map001_data));
-
-    if (NULL != map->data) {
-        map001_reset(map, mem);
-        status = 0;
-    }
-
-    return status;
+    map001_reset(map, mem);
+    return 0;
 }
 
 static int map001_write_rom(nes_Mapper* map, nes_Memory* mem,
@@ -156,6 +146,7 @@ static int map001_write_rom(nes_Mapper* map, nes_Memory* mem,
 const nes_Mapper map001 = {
     .name           = "MMC1",
     .max_chr_banks  = 128,
+    .data_size      = sizeof(map001_data),
     .init           = map001_init,
     .reset          = map001_reset,
     .write_rom      = map001_write_rom,

src/map/map002.c

@@ -0,0 +1,44 @@
+#include "memory.h"
+
+
+typedef struct {
+    uint8_t bank;
+} map002_data;
+
+
+static inline void uxrom_set_bank(map002_data* data,
+                                  nes_Memory* mem,
+                                  uint8_t bank) {
+    data->bank = (bank % (mem->n_rom_banks / 2));
+    mem->rom_bank[0] = prg_rom_page(mem, (data->bank * 2) + 0);
+    mem->rom_bank[1] = prg_rom_page(mem, (data->bank * 2) + 1);
+}
+
+static void map002_reset(nes_Mapper* map, nes_Memory* mem) {
+    uxrom_set_bank((map002_data*)map->data, mem, 0);
+}
+
+static int map002_init(nes_Mapper* map, const ines_Header* hdr,
+                       nes_Memory* mem) {
+    int last_bank = (mem->n_rom_banks / 2) - 1;
+    mem->rom_bank[2] = prg_rom_page(mem, (last_bank * 2) + 0);
+    mem->rom_bank[3] = prg_rom_page(mem, (last_bank * 2) + 1);
+    map002_reset(map, mem);
+    return 0;
+}
+
+static int map002_write_rom(nes_Mapper* map, nes_Memory* mem,
+                            uint16_t addr, uint8_t val) {
+    uxrom_set_bank((map002_data*)map->data, mem, val);
+    return 0;
+}
+
+
+const nes_Mapper map002 = {
+    .name           = "UxROM",
+    .max_chr_banks  = 8,
+    .data_size      = sizeof(map002_data),
+    .init           = map002_init,
+    .reset          = map002_reset,
+    .write_rom      = map002_write_rom,
+};

src/mapper.c

@@ -3,8 +3,10 @@
 
 extern const nes_Mapper map000;
 extern const nes_Mapper map001;
+extern const nes_Mapper map002;
 
 const nes_Mapper* nes_mappers[256] = {
     &map000,
     &map001,
+    &map002,
 };

src/mapper.h

@@ -11,6 +11,8 @@ struct nes_Memory;
 struct nes_Mapper {
     const char* name;
     int max_chr_banks;
+    int data_size;
+    void* data;
 
     int (*init)(struct nes_Mapper*, const ines_Header*, struct nes_Memory*);
     void (*done)(struct nes_Mapper*);
@@ -26,8 +28,6 @@ struct nes_Mapper {
 
     void (*ppu_bus)(struct nes_Mapper*, uint16_t addr);
     void (*ppu_mem_mode)(struct nes_Mapper*, uint8_t mode);
-
-    void* data;
 };
 typedef struct nes_Mapper nes_Mapper;