diff --git a/src/mesa/shader/nvfragparse.c b/src/mesa/shader/nvfragparse.c
index 364c706..1361041 100644
--- a/src/mesa/shader/nvfragparse.c
+++ b/src/mesa/shader/nvfragparse.c
@@ -1009,14 +1009,14 @@
       srcReg->Index = idx;
    }
    else if (token[0] == 'f') {
-      /* XXX this might be an identier! */
+      /* XXX this might be an identifier! */
       srcReg->File = PROGRAM_INPUT;
       if (!Parse_FragReg(parseState, &idx))
          RETURN_ERROR;
       srcReg->Index = idx;
    }
    else if (token[0] == 'p') {
-      /* XXX this might be an identier! */
+      /* XXX this might be an identifier! */
       srcReg->File = PROGRAM_LOCAL_PARAM;
       if (!Parse_ProgramParamReg(parseState, &idx))
          RETURN_ERROR;
@@ -1146,6 +1146,20 @@
       srcReg->File = PROGRAM_NAMED_PARAM;
       srcReg->Index = paramIndex;      
    }
+   else if (IsLetter(token[0])){
+      /* named param/constant */
+      GLubyte ident[100];
+      GLint paramIndex;
+      if (!Parse_Identifier(parseState, ident))
+         RETURN_ERROR;
+      paramIndex = _mesa_lookup_parameter_index(parseState->parameters,
+                                                -1, (const char *) ident);
+      if (paramIndex < 0) {
+         RETURN_ERROR2("Undefined constant or parameter: ", ident);
+      }
+      srcReg->File = PROGRAM_NAMED_PARAM;
+      srcReg->Index = paramIndex;      
+   }
    else if (IsDigit(token[0])) {
       /* scalar literal */
       GLfloat values[4];