Fix BASIC

src/io.c

@@ -13,5 +13,20 @@ int getChar(void) {
 
   int c = getchar();
 
+  // Specifically send FF for EOF to trigger echo cancellation
+  if (c == EOF) {
+    return 0xFF;
+  }
+
+  // BASIC expects CR always
+  if (c == '\n') {
+    return '\r';
+  }
+
+  // BASIC is uppercase only
+  if (c >= 'a' && c <= 'z') {
+    c = c - 'a' + 'A';
+  }
+
   return c;
 }

src/memoryMap.c

@@ -26,25 +26,34 @@ uint8_t readMemory(uint16_t address, uint8_t *ram, uint8_t *rom) {
 }
 
 void writeMemory(uint16_t address, uint8_t value, uint8_t *ram) {
-  if ((address < RAM_SIZE && address < IO_BASE) || address >= ROM_BASE) {
-    if (address < ROM_BASE && ram[IO_BASE + ROM_BANKED_OUT] != 0) {
+  /* Normal RAM */
+  if (address < IO_BASE) {
+    ram[address] = value;
+    return;
+  }
+
+  /* ROM area */
+  if (address >= ROM_BASE) {
+    if (ram[IO_BASE + ROM_BANKED_OUT] != 0) {
       ram[address] = value;
     }
-  } else {
-    uint16_t _address = address - IO_BASE;
-    switch (_address) {
-      case SCREEN_ADDRESS: {
-        putChar(value);
-        break;
-      }
-      case ROM_BANKED_OUT: {
-        ram[IO_BASE + ROM_BANKED_OUT] = value;
-        break;
-      }
+    return;
+  }
 
-      default:
-        break;
-    }
+  /* I/O area */
+  uint16_t _address = address - IO_BASE;
+
+  switch (_address) {
+    case SCREEN_ADDRESS:
+      putChar(value);
+      break;
+
+    case ROM_BANKED_OUT:
+      ram[IO_BASE + ROM_BANKED_OUT] = value;
+      break;
+
+    default:
+      break;
   }
 }