diff --git a/src/compiler/new-assem.lisp b/src/compiler/new-assem.lisp
index d9fdb32fb4343980652fe7b2cbef1c8726fc7ea1..f6179dea4e815a494807f063d07932695fcdae9e 100644
--- a/src/compiler/new-assem.lisp
+++ b/src/compiler/new-assem.lisp
@@ -1553,8 +1553,8 @@
 			  (quo rem)
 			  (truncate total-bits assembly-unit-bits)
 			(unless (zerop rem)
-			  (error (intl:gettext "~D isn't an even multiple of ~D")
-				 total-bits assembly-unit-bits))
+			  (error (intl:gettext "~D isn't an even multiple of ~D in emitter ~S")
+				 total-bits assembly-unit-bits name))
 			quo))
 	   (bytes (make-array num-bytes :initial-element nil))
 	   (segment-arg (gensym "SEGMENT-")))
@@ -1565,8 +1565,8 @@
 	       (arg (gensym (format nil "~:@(ARG-FOR-~S-~)" byte-spec-expr))))
 	  (when (ldb-test (byte byte-size byte-posn) overall-mask)
 	    (error (intl:gettext "Byte spec ~S either overlaps another byte spec, or ~
-		    extends past the end.")
-		   byte-spec-expr))
+		    extends past the end in emitter ~S.")
+		   byte-spec-expr name))
 	  (setf (ldb byte-spec overall-mask) -1)
 	  (arg-names arg)
 	  (arg-types `(type (integer ,(ash -1 (1- byte-size))