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20 Jan 2004 23:53:32 -0500
Gnus/5.09 (Gnus v5.9.0) Emacs/21.3.50
I've just installed code that should make it possible to use low-bits for
tags, thus allowing the use of the whole address space for lisp data.
By default, things should work exactly as before, but if you define
USE_LSB_TAG, then the new tagging should be used. Things to note:
- if you use a compiler other than gcc, you will need to provide
a definition of DECL_ALIGN, otherwise USE_LSB_TAG will be ignored.
Please add the relevant definition to src/s/*.h or src/m/*.h or
src/lisp.h or post it here if you don't know where to put it.
- this will lead to errors if your malloc does not always return addresses
that are multiple-of-8.
- please also define ENABLE_CHECKING when using this new code.
- scratch that: please always use ENABLE_CHECKING.
- the .gdbinit file has not been updated, so gdb commands like xtype and
friends won't do the right thing.
- Also, please try it with the attached patch below to see if your system
can be automatically selected to USE_LSB_TAG. It seems that s/darwin.h
can also set USE_LSB_TAG. Tell me of other systems where USE_LSB_TAG
can be set. I'm especially interested to hear about systems where it
would be really useful such as on Mac OS 9 or FreeBSD.
- tell me if it works. Tell me if it doesn't.
--- lisp.h.~1.476.~ Tue Jan 20 23:29:29 2004
+++ lisp.h Tue Jan 20 23:46:34 2004
@@ -291,6 +291,11 @@
/***** Select the tagging scheme. *****/
+/* Try to USE_LSB_TAG on systems where we know malloc returns multiple-of-8 */
+#if defined GNU_MALLOC || defined DOUG_LEA_MALLOC || defined __GLIBC__
/* First, try and define DECL_ALIGN(type,var) which declares a static
variable VAR of type TYPE with the added requirement that it be
Stefan Monnier <=