Initial commit

src/snes/cart.c

@@ -0,0 +1,116 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <assert.h>
+
+#include "cart.h"
+#include "snes.h"
+
+static uint8_t cart_readLorom(Cart* cart, uint8_t bank, uint16_t adr);
+static void cart_writeLorom(Cart* cart, uint8_t bank, uint16_t adr, uint8_t val);
+static uint8_t cart_readHirom(Cart* cart, uint8_t bank, uint16_t adr);
+static void cart_writeHirom(Cart* cart, uint8_t bank, uint16_t adr, uint8_t val);
+
+Cart* cart_init(Snes* snes) {
+  Cart* cart = malloc(sizeof(Cart));
+  cart->snes = snes;
+  cart->type = 0;
+  cart->rom = NULL;
+  cart->romSize = 0;
+  cart->ram = NULL;
+  cart->ramSize = 0;
+  return cart;
+}
+
+void cart_free(Cart* cart) {
+  free(cart);
+}
+
+void cart_reset(Cart* cart) {
+  //if(cart->ramSize > 0 && cart->ram != NULL) memset(cart->ram, 0, cart->ramSize); // for now
+}
+
+void cart_saveload(Cart *cart, SaveLoadFunc *func, void *ctx) {
+  func(ctx, cart->ram, cart->ramSize);
+}
+
+void cart_load(Cart* cart, int type, uint8_t* rom, int romSize, int ramSize) {
+  cart->type = type;
+  if(cart->rom != NULL) free(cart->rom);
+  if(cart->ram != NULL) free(cart->ram);
+  cart->rom = malloc(romSize);
+  cart->romSize = romSize;
+  if(ramSize > 0) {
+    cart->ram = malloc(ramSize);
+    memset(cart->ram, 0, ramSize);
+  } else {
+    cart->ram = NULL;
+  }
+  cart->ramSize = ramSize;
+  memcpy(cart->rom, rom, romSize);
+}
+
+uint8_t cart_read(Cart* cart, uint8_t bank, uint16_t adr) {
+  switch(cart->type) {
+    case 0: 
+      assert(0);
+      return cart->snes->openBus;
+    case 1: return cart_readLorom(cart, bank, adr);
+    case 2: return cart_readHirom(cart, bank, adr);
+  }
+  assert(0);
+  return cart->snes->openBus;
+}
+
+void cart_write(Cart* cart, uint8_t bank, uint16_t adr, uint8_t val) {
+  switch(cart->type) {
+    case 0: break;
+    case 1: cart_writeLorom(cart, bank, adr, val); break;
+    case 2: cart_writeHirom(cart, bank, adr, val); break;
+  }
+}
+
+static uint8_t cart_readLorom(Cart* cart, uint8_t bank, uint16_t adr) {
+  if(((bank >= 0x70 && bank < 0x7e) || bank >= 0xf0) && adr < 0x8000 && cart->ramSize > 0) {
+    // banks 70-7e and f0-ff, adr 0000-7fff
+    return cart->ram[(((bank & 0xf) << 15) | adr) & (cart->ramSize - 1)];
+  }
+  bank &= 0x7f;
+  if(adr >= 0x8000 || bank >= 0x40) {
+    // adr 8000-ffff in all banks or all addresses in banks 40-7f and c0-ff
+    return cart->rom[((bank << 15) | (adr & 0x7fff)) & (cart->romSize - 1)];
+  }
+  assert(0);
+  return cart->snes->openBus;
+}
+
+static void cart_writeLorom(Cart* cart, uint8_t bank, uint16_t adr, uint8_t val) {
+  if(((bank >= 0x70 && bank < 0x7e) || bank > 0xf0) && adr < 0x8000 && cart->ramSize > 0) {
+    // banks 70-7e and f0-ff, adr 0000-7fff
+    cart->ram[(((bank & 0xf) << 15) | adr) & (cart->ramSize - 1)] = val;
+  }
+}
+
+static uint8_t cart_readHirom(Cart* cart, uint8_t bank, uint16_t adr) {
+  bank &= 0x7f;
+  if(bank < 0x40 && adr >= 0x6000 && adr < 0x8000 && cart->ramSize > 0) {
+    // banks 00-3f and 80-bf, adr 6000-7fff
+    return cart->ram[(((bank & 0x3f) << 13) | (adr & 0x1fff)) & (cart->ramSize - 1)];
+  }
+  if(adr >= 0x8000 || bank >= 0x40) {
+    // adr 8000-ffff in all banks or all addresses in banks 40-7f and c0-ff
+    return cart->rom[(((bank & 0x3f) << 16) | adr) & (cart->romSize - 1)];
+  }
+  assert(0);
+  return cart->snes->openBus;
+}
+
+static void cart_writeHirom(Cart* cart, uint8_t bank, uint16_t adr, uint8_t val) {
+  bank &= 0x7f;
+  if(bank < 0x40 && adr >= 0x6000 && adr < 0x8000 && cart->ramSize > 0) {
+    // banks 00-3f and 80-bf, adr 6000-7fff
+    cart->ram[(((bank & 0x3f) << 13) | (adr & 0x1fff)) & (cart->ramSize - 1)] = val;
+  }
+}