From 8c5480309446e74f776e5a0d981d69e84e6f50cb Mon Sep 17 00:00:00 2001
From: Stephen Williams <steve@icarus.com>
Date: Wed, 25 Jun 2008 13:59:39 -0700
Subject: [PATCH] vpi_get_value of integer values replaces x/z bits with 0.

In arithmetic expressions, vectors with x/z are replaced with 0,
but vpi_get_value replaces x/z bits with 0 bits without replacing
the whole vector.
---
 vvp/vpi_signal.cc |  3 +--
 vvp/vvp_net.cc    | 11 ++++++++---
 vvp/vvp_net.h     |  9 ++++++++-
 3 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/vvp/vpi_signal.cc b/vvp/vpi_signal.cc
index 54ef5dd47..c3bdf03e9 100644
--- a/vvp/vpi_signal.cc
+++ b/vvp/vpi_signal.cc
@@ -298,8 +298,7 @@ static void format_vpiIntVal(vvp_fun_signal_vec*sig, int base, unsigned wid,
 {
       vvp_vector4_t sub = sig->vec4_value().subvalue(base, wid);
       long val = 0;
-      bool flag = vector4_to_value(sub, val, signed_flag);
-      if (! flag) val = 0;
+      bool flag = vector4_to_value(sub, val, signed_flag, false);
       vp->value.integer = val;
 }
 
diff --git a/vvp/vvp_net.cc b/vvp/vvp_net.cc
index b9d6b60be..eb5f154b4 100644
--- a/vvp/vvp_net.cc
+++ b/vvp/vvp_net.cc
@@ -1133,10 +1133,12 @@ ostream& operator<< (ostream&out, const vvp_vector4_t&that)
       return out;
 }
 
-bool vector4_to_value(const vvp_vector4_t&vec, long&val, bool is_signed)
+bool vector4_to_value(const vvp_vector4_t&vec, long&val,
+		      bool is_signed, bool is_arithmetic)
 {
       long res = 0;
       long msk = 1;
+      bool rc_flag = true;
 
       for (unsigned idx = 0 ;  idx < vec.size() ;  idx += 1) {
 	    switch (vec.value(idx)) {
@@ -1146,7 +1148,10 @@ bool vector4_to_value(const vvp_vector4_t&vec, long&val, bool is_signed)
 		  res |= msk;
 		  break;
 		default:
-		  return false;
+		  if (is_arithmetic)
+			return false;
+		  else
+			rc_flag = false;
 	    }
 
 	    msk <<= 1L;
@@ -1158,7 +1163,7 @@ bool vector4_to_value(const vvp_vector4_t&vec, long&val, bool is_signed)
       }
 
       val = res;
-      return true;
+      return rc_flag;
 }
 
 bool vector4_to_value(const vvp_vector4_t&vec, unsigned long&val)
diff --git a/vvp/vvp_net.h b/vvp/vvp_net.h
index 832689e72..2d352c4e3 100644
--- a/vvp/vvp_net.h
+++ b/vvp/vvp_net.h
@@ -381,8 +381,15 @@ template <class T> extern T coerce_to_width(const T&that, unsigned width);
  * place (this follows the rules of Verilog conversions from vector4
  * to real and integers) and the return value becomes false to
  * indicate an error.
+ *
+ * The "is_arithmetic" flag true will cause a result to be entirely 0
+ * if any bits are X/Z. That is normally what you want if this value
+ * is in the midst of an arithmetic expression. If is_arithmetic=false
+ * then the X/Z bits will be replaced with 0 bits, and the return
+ * value will be "false", but the other bits will be transferred. This
+ * is what you want if you are doing "vpi_get_value", for example.
  */
-extern bool vector4_to_value(const vvp_vector4_t&a, long&val, bool is_signed);
+extern bool vector4_to_value(const vvp_vector4_t&a, long&val, bool is_signed, bool is_arithmetic =true);
 extern bool vector4_to_value(const vvp_vector4_t&a, unsigned long&val);
 extern bool vector4_to_value(const vvp_vector4_t&a, double&val, bool is_signed);