diff --git a/ChangeLog b/ChangeLog
index 4ccc57d296..3051dce859 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Sat Dec 22 03:54:18 2007  Yukihiro Matsumoto  <matz@ruby-lang.org>
+
+	* encoding.c (rb_ascii_encoding): renamed from previous
+	  rb_default_encoding().
+
 Sat Dec 22 02:49:02 2007  Yukihiro Matsumoto  <matz@ruby-lang.org>
 
 	* parse.y (command): block from cmd_brace_block was ignored.
diff --git a/encoding.c b/encoding.c
index 5e60f95ad4..2f77f02d08 100644
--- a/encoding.c
+++ b/encoding.c
@@ -236,7 +236,7 @@ rb_define_dummy_encoding(const char *name)
     enc_check_duplication(name);
     if (index < ENCODING_INLINE_MAX) index = ENCODING_INLINE_MAX;
     if (enc_table_expand(index + 1) < 0) return -1;
-    encoding = rb_default_encoding();
+    encoding = rb_ascii_encoding();
     enc_register_at(index, name, encoding);
     enc = set_based_encoding(index, encoding);
     FL_SET(enc, ENC_DUMMY);
@@ -742,7 +742,7 @@ enc_load(VALUE klass, VALUE str)
 }
 
 rb_encoding *
-rb_default_encoding(void)
+rb_ascii_encoding(void)
 {
     if (!enc_table) {
 	rb_enc_init();
diff --git a/include/ruby/encoding.h b/include/ruby/encoding.h
index 46ecf2c173..db19ee9d70 100644
--- a/include/ruby/encoding.h
+++ b/include/ruby/encoding.h
@@ -115,7 +115,7 @@ int rb_enc_str_coderange(VALUE);
 int rb_enc_str_asciionly_p(VALUE);
 #define rb_enc_str_asciicompat_p(str) rb_enc_asciicompat(rb_enc_get(str))
 VALUE rb_enc_from_encoding(rb_encoding *enc);
-rb_encoding *rb_default_encoding(void);
+rb_encoding *rb_ascii_encoding(void);
 rb_encoding *rb_utf8_encoding(void);
 rb_encoding *rb_default_external_encoding(void);
 VALUE rb_enc_default_external(void);
diff --git a/io.c b/io.c
index 06a0c3aa23..567e7b5d5d 100644
--- a/io.c
+++ b/io.c
@@ -2862,7 +2862,7 @@ rb_io_binmode(VALUE io)
 
 #endif
     fptr->mode |= FMODE_BINMODE;
-    fptr->enc = rb_default_encoding();
+    fptr->enc = rb_ascii_encoding();
     return io;
 }
 
diff --git a/numeric.c b/numeric.c
index 45a9ce025e..a152c340d9 100644
--- a/numeric.c
+++ b/numeric.c
@@ -1860,7 +1860,7 @@ int_chr(int argc, VALUE *argv, VALUE num)
 	break;
     }
     enc = rb_to_encoding(argv[0]);
-    if (!enc) enc = rb_default_encoding();
+    if (!enc) enc = rb_ascii_encoding();
     if (i < 0 || (n = rb_enc_codelen(i, enc)) <= 0) goto out_of_range;
     str = rb_enc_str_new(0, n, enc);
     rb_enc_mbcput(i, RSTRING_PTR(str), enc);
diff --git a/re.c b/re.c
index e23a1b7622..971d3e667b 100644
--- a/re.c
+++ b/re.c
@@ -954,7 +954,7 @@ rb_reg_prepare_re(VALUE re, VALUE str)
             need_recompile = 1;
         }
         if ((RBASIC(re)->flags & REG_ENCODING_NONE) &&
-	    enc != rb_default_encoding() &&
+	    enc != rb_ascii_encoding() &&
             rb_enc_str_coderange(str) != ENC_CODERANGE_7BIT) {
             rb_warn("none encoding regexp with non ASCII string (string encoding: %s)",
                     rb_enc_name(enc));
@@ -1964,7 +1964,7 @@ rb_reg_initialize(VALUE obj, const char *s, int len, rb_encoding *enc,
     struct RRegexp *re = RREGEXP(obj);
     VALUE unescaped;
     rb_encoding *fixed_enc = 0;
-    rb_encoding *d_enc = rb_default_encoding();
+    rb_encoding *a_enc = rb_ascii_encoding();
 
     if (!OBJ_TAINTED(obj) && rb_safe_level() >= 4)
 	rb_raise(rb_eSecurityError, "Insecure: can't modify regexp");
@@ -1982,17 +1982,17 @@ rb_reg_initialize(VALUE obj, const char *s, int len, rb_encoding *enc,
 
     if (fixed_enc) {
 	if ((fixed_enc != enc && (options & ARG_ENCODING_FIXED)) ||
-            (fixed_enc != d_enc && (options & ARG_ENCODING_NONE))) {
+            (fixed_enc != a_enc && (options & ARG_ENCODING_NONE))) {
 	    strcpy(err, "incompatible character encoding");
 	    return -1;
 	}
-        if (fixed_enc != d_enc) {
+        if (fixed_enc != a_enc) {
 	    options |= ARG_ENCODING_FIXED;
 	    enc = fixed_enc;
 	}
     }
     else if (!(options & ARG_ENCODING_FIXED)) {
-        enc = d_enc;
+        enc = a_enc;
     }
 
     rb_enc_associate((VALUE)re, enc);
diff --git a/ruby.c b/ruby.c
index 19b243578f..adb7269ad2 100644
--- a/ruby.c
+++ b/ruby.c
@@ -144,12 +144,12 @@ locale_encoding(void)
     int idx;
 
     if (codeset == Qnil)
-        return rb_default_encoding();
+        return rb_ascii_encoding();
 
     name = StringValueCStr(codeset);
     idx = rb_enc_find_index(name);
     if (idx < 0)
-        return rb_default_encoding();
+        return rb_ascii_encoding();
     return rb_enc_from_index(idx);
 }
 
diff --git a/transcode.c b/transcode.c
index cd3f56dc6b..002024e104 100644
--- a/transcode.c
+++ b/transcode.c
@@ -345,7 +345,7 @@ str_transcode(int argc, VALUE *argv, VALUE *self)
     }
     /* set encoding */
     if (!to_enc) {
-	to_encidx = rb_enc_replicate(to_e, rb_default_encoding());
+	to_encidx = rb_enc_replicate(to_e, rb_ascii_encoding());
     }
     *self = dest;