+\r
+/**\r
+ * Function tap_state_transition\r
+ * takes a current TAP state and returns the next state according to the tms value.\r
+ *\r
+ * Even though there is code to duplicate this elsewhere, we do it here a little\r
+ * differently just to get a second opinion, i.e. a verification, on state tracking\r
+ * in that other logic. Plus array lookups without index checking are no favorite thing.\r
+ * This is educational for developers new to TAP controllers.\r
+ */\r
+static tap_state_t tap_state_transition(tap_state_t cur_state, int tms)\r
+{\r
+ tap_state_t new_state;\r
+\r
+ if (tms)\r
+ {\r
+ switch (cur_state)\r
+ {\r
+ case TAP_RESET:\r
+ new_state = cur_state;\r
+ break;\r
+ case TAP_IDLE:\r
+ case TAP_DRUPDATE:\r
+ case TAP_IRUPDATE:\r
+ new_state = TAP_DRSELECT;\r
+ break;\r
+ case TAP_DRSELECT:\r
+ new_state = TAP_IRSELECT;\r
+ break;\r
+ case TAP_DRCAPTURE:\r
+ case TAP_DRSHIFT:\r
+ new_state = TAP_DREXIT1;\r
+ break;\r
+ case TAP_DREXIT1:\r
+ case TAP_DREXIT2:\r
+ new_state = TAP_DRUPDATE;\r
+ break;\r
+ case TAP_DRPAUSE:\r
+ new_state = TAP_DREXIT2;\r
+ break;\r
+ case TAP_IRSELECT:\r
+ new_state = TAP_RESET;\r
+ break;\r
+ case TAP_IRCAPTURE:\r
+ case TAP_IRSHIFT:\r
+ new_state = TAP_IREXIT1;\r
+ break;\r
+ case TAP_IREXIT1:\r
+ case TAP_IREXIT2:\r
+ new_state = TAP_IRUPDATE;\r
+ break;\r
+ case TAP_IRPAUSE:\r
+ new_state = TAP_IREXIT2;\r
+ break;\r
+ default:\r
+ LOG_ERROR( "fatal: invalid argument cur_state=%d", cur_state );\r
+ exit(1);\r
+ break;\r
+ }\r
+ }\r
+ else\r
+ {\r
+ switch (cur_state)\r
+ {\r
+ case TAP_RESET:\r
+ case TAP_IDLE:\r
+ case TAP_DRUPDATE:\r
+ case TAP_IRUPDATE:\r
+ new_state = TAP_IDLE;\r
+ break;\r
+ case TAP_DRSELECT:\r
+ new_state = TAP_DRCAPTURE;\r
+ break;\r
+ case TAP_DRCAPTURE:\r
+ case TAP_DRSHIFT:\r
+ case TAP_DREXIT2:\r
+ new_state = TAP_DRSHIFT;\r
+ break;\r
+ case TAP_DREXIT1:\r
+ case TAP_DRPAUSE:\r
+ new_state = TAP_DRPAUSE;\r
+ break;\r
+ case TAP_IRSELECT:\r
+ new_state = TAP_IRCAPTURE;\r
+ break;\r
+ case TAP_IRCAPTURE:\r
+ case TAP_IRSHIFT:\r
+ case TAP_IREXIT2:\r
+ new_state = TAP_IRSHIFT;\r
+ break;\r
+ case TAP_IREXIT1:\r
+ case TAP_IRPAUSE:\r
+ new_state = TAP_IRPAUSE;\r
+ break;\r
+ default:\r
+ LOG_ERROR( "fatal: invalid argument cur_state=%d", cur_state );\r
+ exit(1);\r
+ break;\r
+ }\r
+ }\r
+\r
+ return new_state;\r
+}\r