diff --git a/driver-vpi/main.c b/driver-vpi/main.c
index bfd1ec77b..1785fbf78 100644
--- a/driver-vpi/main.c
+++ b/driver-vpi/main.c
@@ -236,7 +236,9 @@ static int GetRegistryKey(char *key, char **value)
 	}
 	regKeyBuffer[regKeySize] = 0;		/* makes sure there is a trailing NULL */
 
-	lrv = RegQueryValueEx(hkKey,key,NULL,&regKeyType,regKeyBuffer,&regKeySize);
+	/* This needs an unsigned char *, but for MinGW the char is signed. */
+	lrv = RegQueryValueEx(hkKey, key, NULL, &regKeyType,
+	                      (unsigned char *) regKeyBuffer, &regKeySize);
 	if ((lrv != ERROR_SUCCESS) || (regKeyType != REG_SZ) || (!regKeySize)) {
 		lrv = RegCloseKey(hkKey);
 		free(regKeyBuffer);
@@ -269,7 +271,9 @@ static void SetRegistryKey(char *key, char *value)
 		&res) != ERROR_SUCCESS)
 			return;
 
-	RegSetValueEx(hkKey,key,0,REG_SZ,value,strlen(value)+1);
+	/* This needs an unsigned char *, but for MinGW the char is signed. */
+	RegSetValueEx(hkKey, key, 0, REG_SZ, (unsigned char *) value,
+	              strlen(value)+1);
 	RegCloseKey(hkKey);
 
 	printf("info:  storing %s in Windows' registry entry\n",value);
diff --git a/t-dll.cc b/t-dll.cc
index a06c76b3d..a5279a127 100644
--- a/t-dll.cc
+++ b/t-dll.cc
@@ -2283,7 +2283,7 @@ bool dll_target::net_const(const NetConst*net)
       unsigned idx;
       char*bits;
       static char*bits_tmp = 0;
-      static size_t bits_cnt = 0;
+      static unsigned bits_cnt = 0;
 
       struct ivl_net_const_s *obj = new struct ivl_net_const_s;
 
@@ -2298,7 +2298,7 @@ bool dll_target::net_const(const NetConst*net)
 	    bits = obj->b.bit_;
 
       } else {
-	    if (obj->width_+1 > bits_cnt) {
+	    if (obj->width_ >= bits_cnt) {
 		  bits_tmp = (char*)realloc(bits_tmp, obj->width_+1);
 		  bits_cnt = obj->width_+1;
 	    }
diff --git a/vvp/main.cc b/vvp/main.cc
index bb447731f..bdfb3913c 100644
--- a/vvp/main.cc
+++ b/vvp/main.cc
@@ -372,18 +372,34 @@ int main(int argc, char*argv[])
       }
 
       if (verbose_flag) {
+#ifdef __MINGW32__  /* MinGW does not know about z. */
+	    vpi_mcd_printf(1, " ... %8lu functors (net_fun pool=%u bytes)\n",
+#else
 	    vpi_mcd_printf(1, " ... %8lu functors (net_fun pool=%zu bytes)\n",
+#endif
 			   count_functors, vvp_net_fun_t::heap_total());
 	    vpi_mcd_printf(1, "           %8lu logic\n",  count_functors_logic);
 	    vpi_mcd_printf(1, "           %8lu bufif\n",  count_functors_bufif);
 	    vpi_mcd_printf(1, "           %8lu resolv\n",count_functors_resolv);
 	    vpi_mcd_printf(1, "           %8lu signals\n", count_functors_sig);
+#ifdef __MINGW32__  /* MinGW does not know about z. */
+	    vpi_mcd_printf(1, " ... %8lu filters (net_fil pool=%u bytes)\n",
+#else
 	    vpi_mcd_printf(1, " ... %8lu filters (net_fil pool=%zu bytes)\n",
+#endif
 			   count_filters, vvp_net_fil_t::heap_total());
+#ifdef __MINGW32__  /* MinGW does not know about z. */
+	    vpi_mcd_printf(1, " ... %8lu opcodes (%u bytes)\n",
+#else
 	    vpi_mcd_printf(1, " ... %8lu opcodes (%zu bytes)\n",
+#endif
 	                   count_opcodes, size_opcodes);
 	    vpi_mcd_printf(1, " ... %8lu nets\n",     count_vpi_nets);
+#ifdef __MINGW32__  /* MinGW does not know about z. */
+	    vpi_mcd_printf(1, " ... %8lu vvp_nets (%u bytes)\n",
+#else
 	    vpi_mcd_printf(1, " ... %8lu vvp_nets (%zu bytes)\n",
+#endif
 			   count_vvp_nets, size_vvp_nets);
 	    vpi_mcd_printf(1, " ... %8lu arrays (%lu words)\n",
 			   count_net_arrays, count_net_array_words);