(cp-coding-system-for-codepage-1): On MS-DOS,

use dos-unsupported-char-glyph for characters not
supported by the codepage.
(cp-make-coding-systems-for-codepage): Likewise.

1 files changed, 14 insertions, 4 deletions

diff --git a/lisp/international/codepage.el b/lisp/international/codepage.el
index f4990ec2104..9d5e7872cb6 100644
--- a/lisp/international/codepage.el
+++ b/lisp/international/codepage.el
@@ -58,6 +58,11 @@ for these coding systems only support DOS and Unix style EOLs (the -mac
 variety is actually just an alias for the -unix variety)."
   (save-match-data
     (let* ((coding-name (symbol-name coding))
+           (undef (if (eq system-type 'ms-dos)
+                      (if dos-unsupported-char-glyph
+                          (logand dos-unsupported-char-glyph 255)
+                        127)
+                    ??))
            (ccl-decoder-dos
             (ccl-compile
              `(4 (loop (read r1)
@@ -89,7 +94,7 @@ variety is actually just an alias for the -unix variety)."
                          (if (r0 != ,(charset-id 'ascii))
                              ((translate-character ,encoder r0 r1)
                               (if (r0 == ,(charset-id 'japanese-jisx0208))
-                                  ((r1 = ??)
+                                  ((r1 = ,undef)
                                    (write r1))))))
                        (write-repeat r1)))))
            (ccl-encoder-unix
@@ -98,7 +103,7 @@ variety is actually just an alias for the -unix variety)."
                        (if (r0 != ,(charset-id 'ascii))
                            ((translate-character ,encoder r0 r1)
                             (if (r0 == ,(charset-id 'japanese-jisx0208))
-                                ((r1 = ??)
+                                ((r1 = ,undef)
                                  (write r1)))))
                        (write-repeat r1))))))
       (if (memq coding coding-system-list)
@@ -436,14 +441,19 @@ decoder and encoder created by this function."
     ;; For charsets other than ascii and ISO-NAME, set `?' for
     ;; one-column charsets, and some Japanese character for
     ;; wide-column charsets.  CCL encoder convert that Japanese
-    ;; character to "??".
+    ;; character to either dos-unsupported-char-glyph or "??".
     (let ((tbl (char-table-extra-slot (symbol-value nonascii-table) 0))
+          (undef (if (eq system-type 'ms-dos)
+                     (if dos-unsupported-char-glyph
+                         (logand dos-unsupported-char-glyph 255)
+                       127)
+                   ??))
           (charsets (delq 'ascii (delq iso-name
                                        (copy-sequence charset-list))))
           (wide-column-char (make-char 'japanese-jisx0208 32 32)))
       (while charsets
         (aset tbl (make-char (car charsets))
-              (if (= (charset-width (car charsets)) 1) ?? wide-column-char))
+              (if (= (charset-width (car charsets)) 1) undef wide-column-char))
         (setq charsets (cdr charsets))))
     (define-translation-table decode-translation
       (symbol-value nonascii-table))