undocumented opcodes added to ncpu

[fceu.git] / ncpu.h

diff --git a/ncpu.h b/ncpu.h
index 015320a..ac46a33 100644 (file)
--- a/ncpu.h
+++ b/ncpu.h
@@ -37,7 +37,7 @@
 #define REG_P_REST r8
 #define REG_NZ  r9             // 14
 #define REG_ADDR r10           // 18
-#define REG_CYCLE r11          // 1c
+#define REG_CYCLE r11          // 1c [31:16] - fceu cycles, [15:8] - fceu irqhook cycles, [7:0] - fceu timestamp cycles
 #define REG_OP_TABLE r12       // 20
 
 
@@ -78,7 +78,8 @@
  * note: fceu uses this differently
  * [7:0]   - interrupt flags (same as above)
  * [15:8]  - FCEU IRQ pending sources
- * [23:16] - unused
+ * [16]    - a flag which indicates that MapIRQHook is not null
+ * [23:17] - unused
  * [31:24] - stack pointer
  */