diff --git a/vpi/sys_fileio.c b/vpi/sys_fileio.c
index 305775390..667d78fef 100644
--- a/vpi/sys_fileio.c
+++ b/vpi/sys_fileio.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003-2010 Stephen Williams (steve@icarus.com)
+ * Copyright (c) 2003-2012 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
@@ -680,7 +680,8 @@ static PLI_INT32 sys_fread_calltf(ICARUS_VPI_CONST PLI_BYTE8*name)
 	    vpi_free_object(argv);
       }
 
-      words = (width+31)/32;
+      assert(width > 0);
+      words = (width - 1)/32 + 1;
       vector = calloc(words, sizeof(s_vpi_vecval));
       bpe = (width+7)/8;
 
diff --git a/vvp/vpi_const.cc b/vvp/vpi_const.cc
index 2b95fe644..f7ca58757 100644
--- a/vvp/vpi_const.cc
+++ b/vvp/vpi_const.cc
@@ -121,7 +121,7 @@ void __vpiStringConst::vpi_get_value(p_vpi_value vp)
 {
       unsigned uint_value;
       p_vpi_vecval vecp;
-      int size = strlen(value_);
+      unsigned size = strlen(value_);
       char*rbuf = 0;
       char*cp;
 
@@ -145,7 +145,7 @@ void __vpiStringConst::vpi_get_value(p_vpi_value vp)
 	      }
 	      rbuf = need_result_buf(size + 1, RBUF_VAL);
 	      uint_value = 0;
-	      for(int i=0; i<size;i ++){
+	      for(unsigned i=0; i<size; i += 1){
 		  uint_value <<=8;
 		  uint_value += (unsigned char)(value_[i]);
 	      }
@@ -156,8 +156,8 @@ void __vpiStringConst::vpi_get_value(p_vpi_value vp)
           case vpiBinStrVal:
 	      rbuf = need_result_buf(8 * size + 1, RBUF_VAL);
 	      cp = rbuf;
-	      for(int i=0; i<size;i ++){
-		  for(int bit=7;bit>=0; bit--){
+	      for(unsigned i=0; i<size; i += 1){
+		  for(int bit=7; bit>=0; bit -= 1){
 		      *cp++ = "01"[ (value_[i]>>bit)&1 ];
 		  }
 	      }
@@ -168,8 +168,8 @@ void __vpiStringConst::vpi_get_value(p_vpi_value vp)
           case vpiHexStrVal:
 	      rbuf = need_result_buf(2 * size + 1, RBUF_VAL);
 	      cp = rbuf;
-	      for(int i=0; i<size;i++){
-		  for(int nibble=1;nibble>=0; nibble--){
+	      for(unsigned i=0; i<size; i += 1){
+		  for(int nibble=1; nibble>=0; nibble -= 1){
 		      *cp++ = "0123456789abcdef"[ (value_[i]>>(nibble*4))&15 ];
 		  }
 	      }
@@ -184,8 +184,8 @@ void __vpiStringConst::vpi_get_value(p_vpi_value vp)
 
           case vpiIntVal:
 	      vp->value.integer = 0;
-	      for(int i=0; i<size;i ++){
-		  for(int bit=7;bit>=0; bit--){
+	      for(unsigned i=0; i<size; i += 1){
+		  for(int bit=7; bit>=0; bit -= 1){
 		      vp->value.integer <<= 1;
 		      vp->value.integer += (value_[i]>>bit)&1;
 		  }
@@ -200,7 +200,7 @@ void __vpiStringConst::vpi_get_value(p_vpi_value vp)
               uint_value = 0;
               vecp = vp->value.vector;
               vecp->aval = vecp->bval = 0;
-	      for(int i=0; i<size;i ++){
+	      for(unsigned i=0; i<size; i += 1){
 		  vecp->aval |= value_[i] << uint_value*8;
 		  uint_value += 1;
 		  if (uint_value > 3) {
diff --git a/vvp/vpi_signal.cc b/vvp/vpi_signal.cc
index dd821c6c4..3478fed40 100644
--- a/vvp/vpi_signal.cc
+++ b/vvp/vpi_signal.cc
@@ -467,7 +467,7 @@ static void format_vpiVectorVal(vvp_signal_value*sig, int base, unsigned wid,
 {
       long end = base + (signed)wid;
       unsigned int obit = 0;
-      unsigned hwid = (wid - 1)/32 + 1;
+      unsigned hwid = (wid + 31)/32;
 
       s_vpi_vecval *op = (p_vpi_vecval)
                          need_result_buf(hwid * sizeof(s_vpi_vecval), RBUF_VAL);