diff --git a/Changes b/Changes
index f739e6fdb..a62e994ce 100644
--- a/Changes
+++ b/Changes
@@ -6,6 +6,8 @@ indicates the contributor was also the author of the fix; Thanks!
 
 * Verilator 3.887 devel
 
+****  Add error on DPI functions > 32 bits, msg1995. [Elliot Mednick]
+
 ****  Fix SystemC compiles with VPI, bug1081. [Arthur Kahlich]
 
 ****  Fix error on wide numbers that represent small msb/lsb, msg1991. [Mandy Xu]
diff --git a/src/V3Task.cpp b/src/V3Task.cpp
index 12a0f5caa..138ff8911 100644
--- a/src/V3Task.cpp
+++ b/src/V3Task.cpp
@@ -584,9 +584,14 @@ private:
 	return new AstCStmt(portp->fileline(), stmt);
     }
 
-    AstNode* createAssignInternalToDpi(AstVar* portp, bool isPtr, const string& frSuffix, const string& toSuffix) {
+    AstNode* createAssignInternalToDpi(AstVar* portp, bool isRtn, bool isPtr,
+				       const string& frSuffix, const string& toSuffix) {
 	// Create assignment from internal format into DPI temporary
 	bool bitvec = (portp->basicp()->isBitLogic() && portp->width() > 32);
+	if (isRtn && bitvec) {
+	    portp->v3error("DPI functions cannot return > 32 bits; use a two-state type or task instead: "<<portp->prettyName());
+	    // Code below works, but won't compile right, and IEEE illegal
+	}
 	string stmt;
 	string ket;
 	// Someday we'll have better type support, and this can make variables and casts.
@@ -727,14 +732,14 @@ private:
 	for (AstNode* stmtp = nodep->stmtsp(); stmtp; stmtp=stmtp->nextp()) {
 	    if (AstVar* portp = stmtp->castVar()) {
 		if (portp->isIO() && portp->isOutput() && !portp->isFuncReturn()) {
-		    dpip->addStmtsp(createAssignInternalToDpi(portp,true,"__Vcvt",""));
+		    dpip->addStmtsp(createAssignInternalToDpi(portp,false,true,"__Vcvt",""));
 		}
 	    }
 	}
 
 	if (rtnvarp) {
 	    dpip->addStmtsp(createDpiTemp(rtnvarp,""));
-	    dpip->addStmtsp(createAssignInternalToDpi(rtnvarp,false,"__Vcvt",""));
+	    dpip->addStmtsp(createAssignInternalToDpi(rtnvarp,true,false,"__Vcvt",""));
 	    string stmt = "return "+rtnvarp->name()+";\n";
 	    dpip->addStmtsp(new AstCStmt(nodep->fileline(), stmt));
 	}
@@ -784,7 +789,7 @@ private:
 
 		    cfuncp->addStmtsp(createDpiTemp(portp,"__Vcvt"));
 		    if (portp->isInput()) {
-			cfuncp->addStmtsp(createAssignInternalToDpi(portp,false,"","__Vcvt"));
+			cfuncp->addStmtsp(createAssignInternalToDpi(portp,false,false,"","__Vcvt"));
 		    }
 		}
 	    }
diff --git a/test_regress/t/t_dpi_exp_bad.pl b/test_regress/t/t_dpi_exp_bad.pl
new file mode 100755
index 000000000..99494afb2
--- /dev/null
+++ b/test_regress/t/t_dpi_exp_bad.pl
@@ -0,0 +1,19 @@
+#!/usr/bin/perl
+if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2003 by Wilson Snyder. This program is free software; you can
+# redistribute it and/or modify it under the terms of either the GNU
+# Lesser General Public License Version 3 or the Perl Artistic License
+# Version 2.0.
+
+compile (
+    v_flags2 => ["--lint-only"],
+    fails=>$Self->{v3},
+    expect=>
+'%Error: t/t_dpi_exp_bad.v:\d+: DPI functions cannot return > 32 bits; use a two-state type or task instead: dpix_f_bit48__Vfuncrtn
+%Error: Exiting due to .*'
+    );
+
+ok(1);
+1;
diff --git a/test_regress/t/t_dpi_exp_bad.v b/test_regress/t/t_dpi_exp_bad.v
new file mode 100644
index 000000000..f051e1ecb
--- /dev/null
+++ b/test_regress/t/t_dpi_exp_bad.v
@@ -0,0 +1,13 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// Copyright 2009 by Wilson Snyder. This program is free software; you can
+// redistribute it and/or modify it under the terms of either the GNU
+// Lesser General Public License Version 3 or the Perl Artistic License
+// Version 2.0.
+
+module t;
+
+   export "DPI-C" function dpix_f_bit48;
+   function bit [47:0]	dpix_f_bit48  (bit [47:0] i); dpix_f_bit48    = ~i;   endfunction
+
+endmodule
diff --git a/test_regress/t/t_dpi_export.v b/test_regress/t/t_dpi_export.v
index 9f02d8f92..bb441d3df 100644
--- a/test_regress/t/t_dpi_export.v
+++ b/test_regress/t/t_dpi_export.v
@@ -38,6 +38,8 @@ module t;
    function longint	dpix_f_longint (longint	 i);  dpix_f_longint  = ~i;   endfunction
    function chandle	dpix_f_chandle (chandle	 i);  dpix_f_chandle  = i;   endfunction
 
+   export "DPI-C" task dpix_t_bit48;
+   task dpix_t_bit48(input bit [47:0] i, output bit [47:0] o);  o = ~i; endtask
    export "DPI-C" task dpix_t_bit95;
    task dpix_t_bit95(input bit [94:0] i, output bit [94:0] o);  o = ~i; endtask
    export "DPI-C" task dpix_t_bit96;
diff --git a/test_regress/t/t_dpi_export_c.cpp b/test_regress/t/t_dpi_export_c.cpp
index 54c41b018..ebf1cca15 100644
--- a/test_regress/t/t_dpi_export_c.cpp
+++ b/test_regress/t/t_dpi_export_c.cpp
@@ -46,6 +46,8 @@ extern "C" {
     extern int dpix_int123();
 
     extern unsigned char dpix_f_bit(unsigned char i);
+    extern svBitVecVal   dpix_f_bit15(const svBitVecVal* i);
+    extern svBitVecVal   dpix_f_bit48(const svBitVecVal* i);
     extern int           dpix_f_int(int i);
     extern char          dpix_f_byte(char i);
     extern short int     dpix_f_shortint(short int i);
@@ -136,6 +138,17 @@ int dpix_run_tests() {
     CHECK_RESULT (unsigned long long, dpix_f_longint(1), 0xfffffffffffffffeULL);
     CHECK_RESULT (void*, dpix_f_chandle((void*)(12345)), (void*)(12345));
 
+    {
+	svBitVecVal i_vec48[2] = {0xab782a12,0x8a413bd9};
+	svBitVecVal o_vec48[2] = {0,0};
+	dpix_t_bit48(i_vec48, o_vec48);
+	CHECK_RESULT(int, o_vec48[0], ~i_vec48[0]);
+#ifdef VCS  // VCS has bug where doesn't clean input
+	CHECK_RESULT(int, o_vec48[1], (~i_vec48[1]));
+#else
+	CHECK_RESULT(int, o_vec48[1], (~i_vec48[1])&0x0000ffffUL);
+#endif
+    }
     {
 	svBitVecVal i_vec95[3] = {0x72912312,0xab782a12,0x8a413bd9};
 	svBitVecVal o_vec95[3] = {0,0,0};