Dick Hollenbeck <dick@softplc.com> part deux of previous changes just committed.

git-svn-id: svn://svn.berlios.de/openocd/trunk@1617 b42882b7-edfa-0310-969c-e2dbd0fdcd60

diff --git a/src/xsvf/xsvf.c b/src/xsvf/xsvf.c
index 17dec493891b8c75392ac82a5e5a185cc2dd11ae..24a14de72f03dfea3b51e06ccd80f930deb504e4 100644 (file)
--- a/src/xsvf/xsvf.c
+++ b/src/xsvf/xsvf.c
@@ -177,13 +177,13 @@ static tap_state_t xsvf_to_tap( int xsvf_state )
 /**
  * Function xsvf_add_statemove
  * moves from the current state to the goal \a state. This needs
- * to be handled according to the xsvf spec, which has nothing
- * to do with the JTAG spec or OpenOCD as such.
- *
- * Implemented via jtag_add_pathmove().
+ * to be handled according to the xsvf spec, see the XSTATE command
+ * description.
  */
-static void xsvf_add_statemove(tap_state_t goal_state)
+static int xsvf_add_statemove(tap_state_t goal_state)
 {
+       int retval = ERROR_OK;
+
        tap_state_t moves[8];
        tap_state_t cur_state = cmd_queue_cur_state;
        int i;
@@ -194,29 +194,69 @@ static void xsvf_add_statemove(tap_state_t goal_state)
                tap_state_name(cur_state),
                tap_state_name(goal_state) );
 
+
+       /*      From the XSVF spec, pertaining to XSTATE:
+
+               For special states known as stable states (Test-Logic-Reset,
+               Run-Test/Idle, Pause-DR, Pause- IR), an XSVF interpreter follows
+               predefined TAP state paths when the starting state is a stable state and
+               when the XSTATE specifies a new stable state (see the STATE command in
+               the [Ref 5] for the TAP state paths between stable states). For
+               non-stable states, XSTATE should specify a state that is only one TAP
+               state transition distance from the current TAP state to avoid undefined
+               TAP state paths. A sequence of multiple XSTATE commands can be issued to
+               transition the TAP through a specific state path.
+       */
+
        if (goal_state==cur_state )
-               return;
+               ;       /* nothing to do */
 
-       if( goal_state==TAP_RESET )
+       else if( goal_state==TAP_RESET )
        {
                jtag_add_tlr();
-               return;
        }
 
-       tms_bits  = tap_get_tms_path(cur_state, goal_state);
-       tms_count = tap_get_tms_path_len(cur_state, goal_state);
+       else if( tap_is_state_stable(cur_state) && tap_is_state_stable(goal_state) )
+       {
+               /*      note: unless tms_bits holds a path that agrees with [Ref 5] in above
+                       spec, then this code is not fully conformant to the xsvf spec.  This
+                       puts a burden on tap_get_tms_path() function from the xsvf spec.
+                       If in doubt, you should confirm that that burden is being met.
+               */
+
+               tms_bits  = tap_get_tms_path(cur_state, goal_state);
+               tms_count = tap_get_tms_path_len(cur_state, goal_state);
 
-       assert( (unsigned) tms_count < DIM(moves) );
+               assert( (unsigned) tms_count < DIM(moves) );
 
-       for (i=0;   i<tms_count;   i++, tms_bits>>=1)
+               for (i=0;   i<tms_count;   i++, tms_bits>>=1)
+               {
+                       bool bit = tms_bits & 1;
+
+                       cur_state = tap_state_transition(cur_state, bit);
+                       moves[i] = cur_state;
+               }
+
+               jtag_add_pathmove(tms_count, moves);
+       }
+
+       /*      else state must be immediately reachable in one clock cycle, and does not
+               need to be a stable state.
+       */
+       else if( tap_state_transition(cur_state, true)  == goal_state
+               ||   tap_state_transition(cur_state, false) == goal_state )
        {
-               bool bit = tms_bits & 1;
+               /* move a single state */
+               moves[0] = goal_state;
+               jtag_add_pathmove( 1, moves );
+       }
 
-               cur_state = tap_state_transition(cur_state, bit);
-               moves[i] = cur_state;
+       else
+       {
+               retval = ERROR_FAIL;
        }
 
-       jtag_add_pathmove(tms_count, moves);
+       return retval;
 }
 
 
@@ -557,7 +597,32 @@ static int handle_xsvf_command(struct command_context_s *cmd_ctx, char *cmd, cha
 
                                LOG_DEBUG("XSTATE 0x%02X %s", uc, tap_state_name(mystate) );
 
-                               xsvf_add_statemove( mystate );
+                               /*      there is no need for the lookahead code that was here since we
+                                       queue up the jtag commands anyway.  This is a simple way to handle
+                                       the XSTATE.
+                               */
+
+                               if( xsvf_add_statemove( mystate ) != ERROR_OK )
+                               {
+                                       /*      For special states known as stable states
+                                               (Test-Logic-Reset, Run-Test/Idle, Pause-DR, Pause- IR),
+                                               an XSVF interpreter follows predefined TAP state paths
+                                               when the starting state is a stable state and when the
+                                               XSTATE specifies a new stable state (see the STATE
+                                               command in the [Ref 5] for the TAP state paths between
+                                               stable states). For non-stable states, XSTATE should
+                                               specify a state that is only one TAP state transition
+                                               distance from the current TAP state to avoid undefined
+                                               TAP state paths. A sequence of multiple XSTATE commands
+                                               can be issued to transition the TAP through a specific
+                                               state path.
+                                       */
+
+                                       LOG_ERROR("XSTATE %s is not reachable from current state %s in one clock cycle",
+                                               tap_state_name(mystate),
+                                               tap_state_name(cmd_queue_cur_state)
+                                               );
+                               }
                        }
                        break;
 
@@ -703,7 +768,7 @@ static int handle_xsvf_command(struct command_context_s *cmd_ctx, char *cmd, cha
 
                                comment[sizeof(comment)-1] = 0;         /* regardless, terminate */
                                if (verbose)
-                                       LOG_USER("\"# %s\"", comment);
+                                       LOG_USER("# %s", comment);
                        }
                        break;