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Adjust comments/debug to match C bignum code

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* doc/lispintro/emacs-lisp-intro.texi (Digression into C):
Adjust to match current C code.
* lisp/emacs-lisp/ert.el (ert--force-message-log-buffer-truncation):
Simplify.
* src/.gdbinit (Lisp_Object_Printer.to_string): Return
a string that says "make_fixnum", not "make_number".
This commit is contained in:
Paul Eggert 2019-06-04 08:29:37 -07:00
parent 7f4558e3d9
commit 741d04a879
3 changed files with 24 additions and 25 deletions
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37
doc/lispintro/emacs-lisp-intro.texi
View file

@ -9014,26 +9014,24 @@ Lisp; it is written in C and is one of the primitives of the GNU Emacs
system. Since it is very simple, I will digress briefly from Lisp and
describe it here.
@c GNU Emacs 24 in src/editfns.c
@c the DEFUN for delete-and-extract-region
@need 1500
Like many of the other Emacs primitives,
@code{delete-and-extract-region} is written as an instance of a C
macro, a macro being a template for code. The complete macro looks
like this:
@c This is a copy of editfns.c's DEFUN for delete-and-extract-region.
@smallexample
@group
DEFUN ("delete-and-extract-region", Fdelete_and_extract_region,
Sdelete_and_extract_region, 2, 2, 0,
doc: /* Delete the text between START and END and return it. */)
(Lisp_Object start, Lisp_Object end)
(Lisp_Object start, Lisp_Object end)
@{
validate_region (&start, &end);
if (XINT (start) == XINT (end))
if (XFIXNUM (start) == XFIXNUM (end))
return empty_unibyte_string;
return del_range_1 (XINT (start), XINT (end), 1, 1);
return del_range_1 (XFIXNUM (start), XFIXNUM (end), 1, 1);
@}
@end group
@end smallexample
@ -9097,9 +9095,9 @@ consists of the following four lines:
@smallexample
@group
validate_region (&start, &end);
if (XINT (start) == XINT (end))
if (XFIXNUM (start) == XFIXNUM (end))
return empty_unibyte_string;
return del_range_1 (XINT (start), XINT (end), 1, 1);
return del_range_1 (XFIXNUM (start), XFIXNUM (end), 1, 1);
@end group
@end smallexample
@ -9111,27 +9109,28 @@ then return an empty string.
The @code{del_range_1} function actually deletes the text. It is a
complex function we will not look into. It updates the buffer and
does other things. However, it is worth looking at the two arguments
passed to @code{del_range_1}. These are @w{@code{XINT (start)}} and
@w{@code{XINT (end)}}.
passed to @code{del_range_1}. These are @w{@code{XFIXNUM (start)}} and
@w{@code{XFIXNUM (end)}}.
As far as the C language is concerned, @code{start} and @code{end} are
two integers that mark the beginning and end of the region to be
deleted@footnote{More precisely, and requiring more expert knowledge
to understand, the two integers are of type @code{Lisp_Object}, which can
also be a C union instead of an integer type.}.
two opaque values that mark the beginning and end of the region to be
deleted. More precisely, and requiring more expert knowledge
to understand, the two values are of type @code{Lisp_Object}, which
might be a C pointer, a C integer, or a C @code{struct}; C code
ordinarily should not care how @code{Lisp_Object} is implemented.
Integer widths depend on the machine, and are typically 32 or 64 bits.
A few of the bits are used to specify the type of information; the
remaining bits are used as content.
@code{Lisp_Object} widths depend on the machine, and are typically 32
or 64 bits. A few of the bits are used to specify the type of
information; the remaining bits are used as content.
@samp{XINT} is a C macro that extracts the relevant number from the
@samp{XFIXNUM} is a C macro that extracts the relevant integer from the
longer collection of bits; the type bits are discarded.
@need 800
The command in @code{delete-and-extract-region} looks like this:
@smallexample
del_range_1 (XINT (start), XINT (end), 1, 1);
del_range_1 (XFIXNUM (start), XFIXNUM (end), 1, 1);
@end smallexample
@noindent

8
lisp/emacs-lisp/ert.el
View file

@ -792,13 +792,13 @@ This mainly sets up debugger-related bindings."
This can be useful after reducing the value of `message-log-max'."
(with-current-buffer (messages-buffer)
;; This is a reimplementation of this part of message_dolog() in xdisp.c:
;; if (NATNUMP (Vmessage_log_max))
;; if (FIXNATP (Vmessage_log_max))
;; {
;; scan_newline (Z, Z_BYTE, BEG, BEG_BYTE,
;; -XFASTINT (Vmessage_log_max) - 1, 0);
;; del_range_both (BEG, BEG_BYTE, PT, PT_BYTE, 0);
;; -XFIXNAT (Vmessage_log_max) - 1, false);
;; del_range_both (BEG, BEG_BYTE, PT, PT_BYTE, false);
;; }
(when (and (integerp message-log-max) (>= message-log-max 0))
(when (natnump message-log-max)
(let ((begin (point-min))
(end (save-excursion
(goto-char (point-max))

4
src/.gdbinit
View file

@ -1316,7 +1316,7 @@ if hasattr(gdb, 'printing'):
itype = ival >> (0 if USE_LSB_TAG else VALBITS)
itype = itype & ((1 << GCTYPEBITS) - 1)
# For a Lisp integer N, yield "make_number(N)".
# For a Lisp fixnum N, yield "make_fixnum(N)".
if itype == Lisp_Int0 or itype == Lisp_Int1:
if USE_LSB_TAG:
ival = ival >> (GCTYPEBITS - 1)
@ -1324,7 +1324,7 @@ if hasattr(gdb, 'printing'):
ival = ival | (-1 << VALBITS)
else:
ival = ival & ((1 << VALBITS) - 1)
return "make_number(%d)" % ival
return "make_fixnum(%d)" % ival
# For non-integers other than nil yield "XIL(N)", where N is a C integer.
# This helps humans distinguish Lisp_Object values from ordinary