Replace libmain:app_main.o with core/app_main.c

core/include/esp/wdev_regs.h

@@ -0,0 +1,30 @@
+/* esp/wdev_regs.h
+ *
+ * ESP8266 register definitions for the "wdev" region (0x3FF2xxx)
+ *
+ * Not compatible with ESP SDK register access code.
+ */
+
+#ifndef _ESP_WDEV_REGS_H
+#define _ESP_WDEV_REGS_H
+
+#include "esp/types.h"
+#include "common_macros.h"
+
+#define WDEV_BASE 0x3FF20000
+#define WDEV (*(struct WDEV_REGS *)(WDEV_BASE))
+
+/* Note: This memory region is not currently well understood.  Pretty much all
+ * of the definitions here are from reverse-engineering the Espressif SDK code,
+ * many are just educated guesses, and almost certainly some are misleading or
+ * wrong.  If you can improve on any of this, please contribute!
+ */
+
+struct WDEV_REGS {
+    uint32_t volatile _unknown[768];  // 0x0000 - 0x0bfc
+    uint32_t volatile SYS_TIME;       // 0x0c00
+} __attribute__ (( packed ));
+
+_Static_assert(sizeof(struct WDEV_REGS) == 0xc04, "WDEV_REGS is the wrong size");
+
+#endif /* _ESP_WDEV_REGS_H */

core/include/esp/wdt_regs.h

@@ -31,6 +31,17 @@ struct WDT_REGS {
 
 _Static_assert(sizeof(struct WDT_REGS) == 0x18, "WDT_REGS is the wrong size");
 
+/* Details for CTRL register */
+
+/* Note: these are currently just guesses based on interpretation of the startup code */
+
+#define WDT_CTRL_ENABLE  BIT(0)
+#define WDT_CTRL_FIELD0_M  0x00000003
+#define WDT_CTRL_FIELD0_S  1
+#define WDT_CTRL_FLAG3  BIT(3)
+#define WDT_CTRL_FLAG4  BIT(4)
+#define WDT_CTRL_FLAG5  BIT(5)
+
 /* Writing WDT_FEED_MAGIC to WDT.FEED register "feeds the dog" and holds off
  * triggering for another cycle (unconfirmed) */
 #define WDT_FEED_MAGIC  0x73