Automatically seed the PIF RAM based on CIC type.

device/device.c

@@ -74,7 +74,7 @@ struct cen64_device *device_create(struct cen64_device *device,
   }
 
   // Initialize the SI.
-  if (si_init(&device->si, &device->bus, pifrom->ptr) < 0) {
+  if (si_init(&device->si, &device->bus, pifrom->ptr, cart->ptr) < 0) {
     printf("create_device: Failed to initialize the SI.\n");
     return NULL;
   }

si/cic.c

@@ -0,0 +1,86 @@
+//
+// si/cic.c: PIF CIC security/lock out algorithms.
+//
+// CEN64: Cycle-Accurate Nintendo 64 Simulator.
+// Copyright (C) 2014, Tyler J. Stachecki.
+//
+// This file is subject to the terms and conditions defined in
+// 'LICENSE', which is part of this source code package.
+//
+
+#include "common.h"
+#include "si/cic.h"
+
+#define CIC_SEED_NUS_6101 0x00063F3FU
+#define CIC_SEED_NUS_6102 0x00023F3FU
+#define CIC_SEED_NUS_6103 0x0002783FU
+#define CIC_SEED_NUS_6105 0x0002913FU
+#define CIC_SEED_NUS_6106 0x0002853FU
+
+#define CRC_NUS_6101 0x6170A4A1U
+#define CRC_NUS_6102 0x90BB6CB5U
+#define CRC_NUS_6103 0x0B050EE0U
+#define CRC_NUS_6105 0x98BC2C86U
+#define CRC_NUS_6106 0xACC8580AU
+
+cen64_cold static uint32_t si_crc32(const uint8_t *data, size_t size);
+
+// Determines the CIC seed for a cart, given the ROM data.
+int get_cic_seed(const uint8_t *rom_data, uint32_t *cic_seed) {
+  uint32_t crc = si_crc32(rom_data + 0x40, 0x1000 - 0x40);
+
+  switch (crc) {
+    case CRC_NUS_6101:
+      *cic_seed = CIC_SEED_NUS_6101;
+      break;
+
+    case CRC_NUS_6102:
+      *cic_seed = CIC_SEED_NUS_6102;
+      break;
+
+    case CRC_NUS_6103:
+      *cic_seed = CIC_SEED_NUS_6103;
+      break;
+
+    case CRC_NUS_6105:
+      *cic_seed = CIC_SEED_NUS_6105;
+      break;
+
+    case CRC_NUS_6106:
+      *cic_seed = CIC_SEED_NUS_6106;
+      break;
+
+    default:
+      *cic_seed = 0;
+      return 1;
+  }
+
+  return 0;
+}
+
+uint32_t si_crc32(const uint8_t *data, size_t size) {
+  uint32_t table[256];
+  unsigned n, k;
+  uint32_t c;
+
+  for (n = 0; n < 256; n++) {
+    c = (uint32_t) n;
+
+    for (k = 0; k < 8; k++) {
+      if (c & 1)
+        c = 0xEDB88320L ^ (c >> 1);
+      else
+        c = c >> 1;
+    }
+
+    table[n] = c;
+  }
+
+  c = 0L ^ 0xFFFFFFFF;
+
+  for (n = 0; n < size; n++)
+    c = table[(c ^ data[n]) & 0xFF] ^ (c >> 8);
+
+  return c ^ 0xFFFFFFFF;
+}
+

si/cic.h

@@ -0,0 +1,17 @@
+//
+// si/cic.h: PIF CIC security/lock out algorithms.
+//
+// CEN64: Cycle-Accurate Nintendo 64 Simulator.
+// Copyright (C) 2014, Tyler J. Stachecki.
+//
+// This file is subject to the terms and conditions defined in
+// 'LICENSE', which is part of this source code package.
+//
+
+#ifndef __si_cic_h__
+#define __si_cic_h__
+
+int get_cic_seed(const uint8_t *rom_data, uint32_t *cic_seed);
+
+#endif
+

si/controller.c

@@ -13,6 +13,7 @@
 #include "bus/controller.h"
 #include "os/main.h"
 #include "ri/controller.h"
+#include "si/cic.h"
 #include "si/controller.h"
 #include "vi/controller.h"
 #include "vr4300/interface.h"
@@ -31,13 +32,22 @@ static int pif_perform_command(struct si_controller *si, unsigned channel,
   uint8_t *send_buf, uint8_t send_bytes, uint8_t *recv_buf, uint8_t recv_bytes);
 
 // Initializes the SI.
-int si_init(struct si_controller *si,
-  struct bus_controller *bus, const uint8_t *rom) {
-  si->bus = bus;
-  si->rom = rom;
+int si_init(struct si_controller *si, struct bus_controller *bus,
+  const uint8_t *pif_rom, const uint8_t *cart_rom) {
+  uint32_t cic_seed;
 
-  si->ram[0x26] = 0x3F;
-  si->ram[0x27] = 0x3F;
+  si->bus = bus;
+  si->rom = pif_rom;
+
+  if (get_cic_seed(cart_rom, &cic_seed)) {
+    printf("Unknown CIC type; is this a byte-swapped ROM?\n");
+    return 1;
+  }
+
+  si->ram[0x24] = cic_seed >> 24;
+  si->ram[0x25] = cic_seed >> 16;
+  si->ram[0x26] = cic_seed >>  8;
+  si->ram[0x27] = cic_seed >>  0;
 
   // Specify 8MiB RDRAM for 6102/6105 carts.
   if (si->ram[0x26] == 0x3F && si->ram[0x27] == 0x3F)

si/controller.h

@@ -36,8 +36,8 @@ struct si_controller {
   uint8_t input[4];
 };
 
-cen64_cold int si_init(struct si_controller *si,
-  struct bus_controller *bus, const uint8_t *rom);
+cen64_cold int si_init(struct si_controller *si, struct bus_controller *bus,
+  const uint8_t *pif_rom, const uint8_t *cart_rom);
 
 int read_pif_ram(void *opaque, uint32_t address, uint32_t *word);
 int read_pif_rom(void *opaque, uint32_t address, uint32_t *word);