Keep the left and right array range value order information.

Previously Icarus normalized the results so array [7:0] would
be the same as array [0:7]. This works just fine for
simulation, but the VPI calls can select the left or right
value and this was incorrect for the [7:0] case since it was
being normalized to [0:7]. This patch swaps the two values in
the a.out file and from this creates the previous first/last
values and a new flag that can be used to get the correct
left and right values for the VPI interface.

ivl.def

@@ -181,6 +181,7 @@ ivl_scope_time_units
 ivl_scope_type
 ivl_scope_tname
 
+ivl_signal_array_addr_swapped
 ivl_signal_array_base
 ivl_signal_array_count
 ivl_signal_attr

ivl_target.h

@@ -1654,10 +1654,12 @@ extern int          ivl_scope_time_units(ivl_scope_t net);
  *
  * ivl_signal_array_base
  * ivl_signal_array_count
+ * ivl_signal_array_addr_swapped
  *    The signal may be arrayed. If so, the array_count is >1. Each
  *    word of the array has its own nexus. The array_base is the
- *    address is the Verilog source for the canonical zero word. This
+ *    address in the Verilog source for the canonical zero word. This
- *    may be negative, positive or zero.
+ *    may be negative, positive or zero. The array addresses may be
+ *    reversed/swapped.
  *
  *    Note that arraying of the signal into words is distinct from the
  *    vectors. The width of a signal is the width of a WORD.
@@ -1736,6 +1738,7 @@ extern int          ivl_scope_time_units(ivl_scope_t net);
 extern ivl_nexus_t ivl_signal_nex(ivl_signal_t net, unsigned word);
 extern int         ivl_signal_array_base(ivl_signal_t net);
 extern unsigned    ivl_signal_array_count(ivl_signal_t net);
+extern unsigned    ivl_signal_array_addr_swapped(ivl_signal_t net);
 extern unsigned    ivl_signal_dimensions(ivl_signal_t net);
 extern ivl_discipline_t ivl_signal_discipline(ivl_signal_t net);
 extern int         ivl_signal_msb(ivl_signal_t net);

netlist.cc

@@ -716,12 +716,20 @@ unsigned NetNet::array_dimensions() const
 
 long NetNet::array_first() const
 {
-      if (s0_ < e0_)
+      if (s0_ <= e0_)
 	    return s0_;
       else
 	    return e0_;
 }
 
+bool NetNet::array_addr_swapped() const
+{
+      if (s0_ <= e0_)
+	     return false;
+      else
+	     return true;
+}
+
 unsigned NetNet::array_count() const
 {
       return calculate_count(s0_, e0_);

netlist.h

@@ -602,6 +602,7 @@ class NetNet  : public NetObj {
 	   indices. (Currently only one array index is supported.) */
       unsigned array_dimensions() const;
       long array_first() const;
+      bool array_addr_swapped() const;
 
 	// This is the number of array elements.
       unsigned array_count() const;

t-dll-api.cc

@@ -1824,6 +1824,11 @@ extern "C" unsigned ivl_signal_array_count(ivl_signal_t net)
       return net->array_words;
 }
 
+extern "C" unsigned ivl_signal_array_addr_swapped(ivl_signal_t net)
+{
+      return net->array_addr_swapped;
+}
+
 extern "C" unsigned ivl_signal_dimensions(ivl_signal_t net)
 {
       return net->array_dimensions_;

t-dll.cc

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2000-2008 Stephen Williams (steve@icarus.com)
+ * Copyright (c) 2000-2009 Stephen Williams (steve@icarus.com)
  *
  *    This source code is free software; you can redistribute it
  *    and/or modify it in source code form under the terms of the GNU
@@ -2559,6 +2559,7 @@ void dll_target::signal(const NetNet*net)
 
       obj->array_base = net->array_first();
       obj->array_words = net->array_count();
+      obj->array_addr_swapped = net->array_addr_swapped() ? 1 : 0;
       if (obj->array_words > 1)
 	    obj->pins = new ivl_nexus_t[obj->array_words];
 

t-dll.h

@@ -639,6 +639,7 @@ struct ivl_signal_s {
 
 	/* For now, support only 0 or 1 array dimensions. */
       unsigned array_dimensions_ : 1;
+      unsigned array_addr_swapped : 1;
 
 	/* These encode the run-time index for the least significant
 	   bit, and the distance to the second bit. */

tgt-vvp/vvp_scope.c

@@ -400,12 +400,13 @@ static void draw_reg_in_scope(ivl_signal_t sig)
 	   write out the .array record to declare the array indices. */
       if (ivl_signal_dimensions(sig) > 0) {
 	    unsigned word_count = ivl_signal_array_count(sig);
+	    unsigned swapped = ivl_signal_array_addr_swapped(sig);
 	    int last = ivl_signal_array_base(sig)+word_count-1;
 	    int first = ivl_signal_array_base(sig);
 	    fprintf(vvp_out, "v%p .array%s \"%s\", %d %d, %d %d;\n",
 		    sig, datatype_flag,
 		    vvp_mangle_name(ivl_signal_basename(sig)),
-		    last, first, msb, lsb);
+		    swapped ? first: last, swapped ? last : first, msb, lsb);
 
       } else {
 
@@ -462,11 +463,12 @@ static void draw_net_in_scope(ivl_signal_t sig)
 			vec8 = "8";
 
 		  if (iword == 0 && dimensions > 0) {
+			unsigned swapped = ivl_signal_array_addr_swapped(sig);
 			int last = ivl_signal_array_base(sig) + word_count-1;
 			int first = ivl_signal_array_base(sig);
 			fprintf(vvp_out, "v%p .array \"%s\", %d %d;\n",
 				sig, vvp_mangle_name(ivl_signal_basename(sig)),
-				last, first);
+				swapped ? first : last, swapped ? last : first);
 		  }
 		  if (dimensions > 0) {
 			/* If this is a word of an array, then use an
@@ -511,12 +513,14 @@ static void draw_net_in_scope(ivl_signal_t sig)
 		    /* An alias for an individual word. */
 		  } else {
 			if (iword == 0) {
+			      unsigned swapped = ivl_signal_array_addr_swapped(sig);
 			      int first = ivl_signal_array_base(sig);
 			      int last = first + word_count-1;
 			      fprintf(vvp_out, "v%p .array \"%s\", %d %d;\n",
 				      sig,
 				      vvp_mangle_name(ivl_signal_basename(sig)),
-				      last, first);
+				      swapped ? first : last,
+				      swapped ? last : first);
 			}
 
 			fprintf(vvp_out, "v%p_%u .alias%s v%p %u, %d %d, "

vvp/array.cc

@@ -102,6 +102,7 @@ struct __vpiArray {
       class vvp_fun_arrayport*ports_;
       struct __vpiCallback *vpi_callbacks;
       bool signed_flag;
+      bool swap_addr;
 };
 
 struct __vpiArrayIterator {
@@ -384,10 +385,12 @@ static vpiHandle vpi_array_get_handle(int code, vpiHandle ref)
       switch (code) {
 
 	  case vpiLeftRange:
-	    return &(obj->first_addr.base);
+	    if (obj->swap_addr) return &(obj->last_addr.base);
+	    else return &(obj->first_addr.base);
 
 	  case vpiRightRange:
-	    return &(obj->last_addr.base);
+	    if (obj->swap_addr) return &(obj->first_addr.base);
+	    else return &(obj->last_addr.base);
 
 	  case vpiScope:
 	    return &obj->scope->base;
@@ -861,6 +864,14 @@ static vpiHandle vpip_make_array(char*label, const char*name,
       obj->signed_flag = signed_flag;
 
 	// Assume increasing addresses.
+      if (last_addr >= first_addr) {
+	    obj->swap_addr = false;
+      } else {
+	    obj->swap_addr = true;
+	    int tmp = last_addr;
+	    last_addr = first_addr;
+	    first_addr = tmp;
+      }
       assert(last_addr >= first_addr);
       unsigned array_count = last_addr+1-first_addr;