Some event control assigns can be skipped so add an event clear.

Since some event control assignments can be skipped we need an
event control clear so that future %evctl statements do not fail
their assert. This patch adds %evctl/c and uses it in the compiler
as appropriate to keep the event control information in sync.

tgt-vvp/vvp_process.c

@@ -349,6 +349,7 @@ static void assign_to_lvector(ivl_lval_t lval, unsigned bit,
 		  fprintf(vvp_out, "    %%assign/v0/x1/e v%p_%lu, %u;\n",
 		          sig, use_word, bit);
 		  fprintf(vvp_out, "t_%u ;\n", skip_assign);
+		  fprintf(vvp_out, "    %%evctl/c;\n");
 	    } else {
 		    /* Constant delay... */
 		  draw_eval_expr_into_integer(part_off_ex, 1);

vvp/codes.h

@@ -82,6 +82,7 @@ extern bool of_DIV_S(vthread_t thr, vvp_code_t code);
 extern bool of_DIV_WR(vthread_t thr, vvp_code_t code);
 extern bool of_END(vthread_t thr, vvp_code_t code);
 extern bool of_EVCTL(vthread_t thr, vvp_code_t code);
+extern bool of_EVCTLC(vthread_t thr, vvp_code_t code);
 extern bool of_EVCTLI(vthread_t thr, vvp_code_t code);
 extern bool of_EVCTLS(vthread_t thr, vvp_code_t code);
 extern bool of_FORCE_LINK(vthread_t thr, vvp_code_t code);

vvp/compile.cc

@@ -126,6 +126,7 @@ const static struct opcode_table_s opcode_table[] = {
       { "%div/wr", of_DIV_WR, 2,  {OA_BIT1,     OA_BIT2,     OA_NONE} },
       { "%end",    of_END,    0,  {OA_NONE,     OA_NONE,     OA_NONE} },
       { "%evctl",  of_EVCTL,  2,  {OA_FUNC_PTR, OA_BIT1,     OA_NONE} },
+      { "%evctl/c",of_EVCTLC, 0,  {OA_NONE,     OA_NONE,     OA_NONE} },
       { "%evctl/i",of_EVCTLI, 2,  {OA_FUNC_PTR, OA_BIT1,     OA_NONE} },
       { "%evctl/s",of_EVCTLS, 2,  {OA_FUNC_PTR, OA_BIT1,     OA_NONE} },
       { "%force/link",of_FORCE_LINK,2,{OA_FUNC_PTR,OA_FUNC_PTR2,OA_NONE} },

vvp/opcodes.txt

@@ -308,6 +308,7 @@ right operand is 0, then the result is NaN.
 
 
 * %evctl <functor-label> <idx>
+* %evctl/c
 * %evctl/s <functor-label> <idx>
 * %evctl/i <functor-label> <value>
 
@@ -318,6 +319,12 @@ by the %assign/e instructions to do not blocking event control. The
 register to read the repetition count from (signed or unsigned).
 %evctl/i sets the repetition to an immediate unsigned value.
 
+%evctl/c clears the event control information. This is needed if a
+%assign/e may be skiped since the %assign/e statements clear the
+event control information and the other %evctl statements assert
+that this information has been cleared. You can get an assert if
+this information is not managed correctly.
+
 
 * %force/v <label>, <bit>, <wid>
 

vvp/vthread.cc

@@ -2061,6 +2061,12 @@ bool of_EVCTL(vthread_t thr, vvp_code_t cp)
       thr->ecount = thr->words[cp->bit_idx[0]].w_uint;
       return true;
 }
+bool of_EVCTLC(vthread_t thr, vvp_code_t)
+{
+      thr->event = 0;
+      thr->ecount = 0;
+      return true;
+}
 
 bool of_EVCTLI(vthread_t thr, vvp_code_t cp)
 {