Mercurial > hg > xemacs-beta
view src/alloca.s @ 5566:4654c01af32b
Improve the implementation, documentation of #'labels, #'flet.
lisp/ChangeLog addition:
2011-09-07 Aidan Kehoe <kehoea@parhasard.net>
* bytecomp.el:
* bytecomp.el (for-effect): Move this earlier in the file, it's
referenced in byte-compile-initial-macro-environment.
* bytecomp.el (byte-compile-initial-macro-environment):
In the byte-compile-macro-environment definition for #'labels, put
off the compiling the lambda bodies until the point where the rest
of the form is being compiled, allowing the lambda bodies to
access appropriate values for byte-compile-bound-variables, and
reducing excessive warning about free variables.
Add a byte-compile-macro-environment definition for #'flet. This
modifies byte-compile-function-environment appropriately, and
warns about bindings of functions that have macro definitions in
the current environment, about functions that have byte codes, and
about functions that have byte-compile methods (which may not do
what the user wants at runtime).
* bytecomp.el (byte-compile-funcall):
If FUNCTION is constant, call #'byte-compile-callargs-warn if
that's appropriate, giving warnings about problems with calling
functions bound with #'labels.
* cl-macs.el:
* cl-macs.el (flet):
Mention the main difference from Common Lisp, that the bindings
are dynamic, not lexical. Counsel the use of #'labels, not #'flet,
for this and other reasons. Explain the limited single use case for
#'flet. Cross-reference to bytecomp.el in a comment.
* cl-macs.el (labels):
Go into detail on which functions may be called from
where. Explain how to access the function definition of a label
within FORM. Add a comment cross-referencing to bytecomp.el.
man/ChangeLog addition:
2011-09-07 Aidan Kehoe <kehoea@parhasard.net>
* cl.texi (Function Bindings):
Move #'labels first, describe it in more detail, explaining that
it is to be preferred over #'flet, and explaining why.
Explain that dynamic bindings with #'flet will also not work when
functions are accessed through their bytecodes.
| author | Aidan Kehoe <kehoea@parhasard.net> |
|---|---|
| date | Wed, 07 Sep 2011 16:26:45 +0100 |
| parents | 308d34e9f07d |
| children |
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/* `alloca' standard 4.2 subroutine for 68000's and 16000's and others. Copyright (C) 1985, 1986, 1988 Free Software Foundation, Inc. This file is part of XEmacs. XEmacs is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. XEmacs is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with XEmacs. If not, see <http://www.gnu.org/licenses/>. */ /* Synched up with: FSF 19.30. */ /* Both 68000 systems I have run this on have had broken versions of alloca. Also, I am told that non-berkeley systems do not have it at all. So replace whatever system-provided alloca there may be on all 68000 systems. */ #define NOT_C_CODE #ifdef emacs #include <config.h> #else #include "config.h" #endif #ifndef HAVE_ALLOCA /* define this to use system's alloca */ #ifndef m68k #ifndef m68000 you lose!! #endif /* m68000 */ #endif /* m68k */ #ifdef m68k /* SGS assembler totally different */ file "alloca.s" global alloca alloca: mov.l (%sp)+,%a1 # pop return addr from top of stack mov.l (%sp)+,%d0 # pop size in bytes from top of stack add.l &R%1,%d0 # round size up to long word and.l &-4,%d0 # mask out lower two bits of size sub.l %d0,%sp # allocate by moving stack pointer tst.b P%1(%sp) # stack probe to allocate pages mov.l %sp,%a0 # return pointer as pointer mov.l %sp,%d0 # return pointer as int to avoid disaster add.l &-4,%sp # new top of stack jmp (%a1) # not a normal return set S%1,64 # safety factor for C compiler scratch set R%1,3+S%1 # add to size for rounding set P%1,-132 # probe this far below current top of stack #else /* not m68k */ #ifdef m68000 /* Some systems want the _, some do not. Win with both kinds. */ .globl _alloca _alloca: .globl alloca alloca: movl sp@+,a0 movl a7,d0 subl sp@,d0 andl #~3,d0 movl d0,sp tstb sp@(0) /* Make stack pages exist */ /* Needed on certain systems that lack true demand paging */ addql #4,d0 jmp a0@ #endif /* m68000 */ #endif /* not m68k */ #endif /* not HAVE_ALLOCA */