[PATCH] * lisp.h (USE_LSB_TAG): Sync comment with code

[PATCH] * lisp.h (USE_LSB_TAG): Sync comment with code

[Lee Duhem]

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Hi,

In `lisp.h', the comment before `USE_LSB_TAG' does not match
the actual code, this patch fixes that. You may want to take a look.

Sincerely,
lee

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From 4ce73b19ca0032b0cfbdd5b8dee0ca07010d3c17 Mon Sep 17 00:00:00 2001
From: Lee Duhem <lee.duhem@gmail.com>
Date: Tue, 25 Nov 2014 09:54:37 +0800
Subject: [PATCH] * lisp.h (USE_LSB_TAG): Sync comment with code.

---
 src/lisp.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/lisp.h b/src/lisp.h
index bdff019..94c524a 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -261,7 +261,8 @@ enum Lisp_Bits
 #define VAL_MAX (EMACS_INT_MAX >> (GCTYPEBITS - 1))
 
 /* Whether the least-significant bits of an EMACS_INT contain the tag.
-   On hosts where pointers-as-ints do not exceed VAL_MAX, USE_LSB_TAG is:
+   On hosts where pointers-as-ints do not exceed EMACS_INT_MAX >> GCTYPEBITS,
+   USE_LSB_TAG is:
     a. unnecessary, because the top bits of an EMACS_INT are unused, and
     b. slower, because it typically requires extra masking.
    So, USE_LSB_TAG is true only on hosts where it might be useful.  */
@@ -272,7 +273,6 @@ DEFINE_GDB_SYMBOL_END (USE_LSB_TAG)
 #if !USE_LSB_TAG && !defined WIDE_EMACS_INT
 # error "USE_LSB_TAG not supported on this platform; please report this." \
 	"Try 'configure --with-wide-int' to work around the problem."
-error !;
 #endif
 
 #ifndef alignas
-- 
1.9.3

Re: [PATCH] * lisp.h (USE_LSB_TAG): Sync comment with code

[Andreas Schwab]

Lee Duhem <lee.duhem@gmail.com> writes:

>  /* Whether the least-significant bits of an EMACS_INT contain the tag.
> -   On hosts where pointers-as-ints do not exceed VAL_MAX, USE_LSB_TAG is:
> +   On hosts where pointers-as-ints do not exceed EMACS_INT_MAX >> GCTYPEBITS,

Aka VAL_MAX / 2.

Andreas.

-- 
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 58CA 54C7 6D53 942B 1756  01D3 44D5 214B 8276 4ED5
"And now for something completely different."

Re: [PATCH] * lisp.h (USE_LSB_TAG): Sync comment with code

[Paul Eggert]

Andreas Schwab wrote:
> Aka VAL_MAX / 2.

Thanks, I installed something along those lines in the Emacs master as commit
366c1ce.