Add Bocfel interpreter

[projects/chimara/chimara.git] / interpreters / bocfel / memory.h

diff --git a/interpreters/bocfel/memory.h b/interpreters/bocfel/memory.h
new file mode 100644 (file)
index 0000000..a53dee3
--- /dev/null
+++ b/interpreters/bocfel/memory.h
@@ -0,0 +1,55 @@
+#ifndef ZTERP_MEMORY_H
+#define ZTERP_MEMORY_H
+
+#include <stdint.h>
+
+#include "util.h"
+#include "zterp.h"
+
+/* Story files do not have access to memory beyond 64K.  If they do
+ * something that would cause such access, wrap appropriately.  This is
+ * the approach Frotz uses (at least for @loadw/@loadb), and is endorsed
+ * by Andrew Plotkin (see http://www.intfiction.org/forum/viewtopic.php?f=38&t=2052).
+ * The standard isn’t exactly clear on the issue, and this appears to be
+ * the most sensible way to deal with the problem.
+ */
+
+extern uint8_t *memory, *dynamic_memory;
+extern uint32_t memory_size;
+
+#define BYTE(addr)             (memory[addr])
+#define STORE_BYTE(addr, val)  ((void)(memory[addr] = (val)))
+
+static inline uint16_t WORD(uint32_t addr)
+{
+#ifndef ZTERP_NO_CHEAT
+  uint16_t cheat_val;
+  if(cheat_find_freezew(addr, &cheat_val)) return cheat_val;
+#endif
+  return (memory[addr] << 8) | memory[addr + 1];
+}
+
+static inline void STORE_WORD(uint32_t addr, uint16_t val)
+{
+  memory[addr + 0] = val >> 8;
+  memory[addr + 1] = val & 0xff;
+}
+
+static inline uint8_t user_byte(uint16_t addr)
+{
+  ZASSERT(addr < header.static_end, "attempt to read out-of-bounds address 0x%lx", (unsigned long)addr);
+
+  return BYTE(addr);
+}
+
+static inline uint16_t user_word(uint16_t addr)
+{
+  ZASSERT(addr < header.static_end - 1, "attempt to read out-of-bounds address 0x%lx", (unsigned long)addr);
+
+  return WORD(addr);
+}
+
+void user_store_byte(uint16_t, uint8_t);
+void user_store_word(uint16_t, uint16_t);
+
+#endif