X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;f=base-target-features.lisp-expr;h=622a1b4a4192684d47273ba1b83271d1ea09c7a8;hb=095564c28a259002c7e34fd1d861f5bbd0a959b6;hp=2bef56042e4bf2b41840a0281e2cc45b46704820;hpb=e1ba5a0d68ff8d4c8e688cd6a951aea1d56b1b61;p=sbcl.git

diff --git a/base-target-features.lisp-expr b/base-target-features.lisp-expr
index 2bef560..622a1b4 100644
--- a/base-target-features.lisp-expr
+++ b/base-target-features.lisp-expr
@@ -107,10 +107,10 @@
  ;; readtable configured so that the system sources can be read.
  ; :sb-show
 
- ;; Build SBCL with the old CMU CL low level debugger, "ldb". If 
- ;; are aren't messing with CMU CL at a very low level (e.g. 
- ;; trying to diagnose GC problems, or trying to debug assembly
- ;; code for a port to a new CPU) you shouldn't need this.
+ ;; Build SBCL with the old CMU CL low level debugger, "ldb". If are
+ ;; aren't messing with SBCL at a very low level (e.g., trying to
+ ;; diagnose GC problems, or trying to debug assembly code for a port
+ ;; to a new CPU) you shouldn't need this.
  ; :sb-ldb
 
  ;; This isn't really a target Lisp feature at all, but controls
@@ -152,30 +152,39 @@
  ; :high-security
  ; :high-security-support
 
- ;; multiprocessing support
+ ;; low-level thread primitives support
  ;;
- ;; This is not maintained or tested in current SBCL. I haven't gone out
- ;; of my way to break it, but since it's derived from an old version of 
- ;; CMU CL where multiprocessing was pretty shaky, it's likely to be very
- ;; flaky now.
- ;;   :MP enables multiprocessing
- ;;   :MP-I486 is used, only within the multiprocessing code, to control
- ;;            what seems to control processor-version-specific code. It's
- ;;            probably for 486 or later, i.e. could be set as long as
- ;;            you know you're not running on a 386, but it doesn't seem
- ;;            to be documented anywhere, so that's just a guess.
- ; :mp
- ; :mp-i486
+ ;; As of SBCL 0.8,  this is only supposed to work in x86 Linux, on which
+ ;; system it's implemented using clone(2) and the %fs segment register.
+ ;; Note that no consistent effort to audit the SBCL library code for
+ ;; thread safety has been performed, so caveat executor.
+ ; :sb-thread
 
+ ;; Kernel support for futexes (so-called "fast userspace mutexes") is
+ ;; available in Linux 2.6 and some versions of 2.4 (Red Hat vendor
+ ;; kernels, possibly other vendors too).  We can take advantage of
+ ;; these to do faster and probably more reliable mutex and condition
+ ;; variable support.  An SBCL built with this feature will fall back
+ ;; to the old system if the futex() syscall is not available at
+ ;; runtime
+ ; :sb-futex
+
+ ;; Support for detection of unportable code (when applied to the
+ ;; COMMON-LISP package, or SBCL-internal pacakges) or bad-neighbourly
+ ;; code (when applied to user-level packages), relating to material
+ ;; alteration to packages or to bindings in symbols in packages.
+ :sb-package-locks
+
+ ;; Support for the entirety of the 21-bit character space defined by
+ ;; the Unicode consortium, rather than the classical 8-bit ISO-8859-1
+ ;; character set.
+ :sb-unicode
+ 
  ;; This affects the definition of a lot of things in bignum.lisp. It
  ;; doesn't seem to be documented anywhere what systems it might apply
  ;; to. It doesn't seem to be needed for X86 systems anyway.
  ; :32x16-divide
 
- ;; This is probably true for some processor types, but not X86. It
- ;; affects a lot of floating point code.
- ; :negative-zero-is-not-zero
-
  ;; This is set in classic CMU CL, and presumably there it means
  ;; that the floating point arithmetic implementation
  ;; conforms to IEEE's standard. Here it definitely means that the
@@ -206,6 +215,10 @@
  ;; in the *FEATURES* list
  ;;
 
+ ;; Any target feature which affects binary compatibility of fasl files
+ ;; needs to be recorded in *FEATURES-POTENTIALLY-AFFECTING-FASL-FORMAT*
+ ;; (elsewhere).
+
  ;; notes on the :NIL and :IGNORE features:
  ;;
  ;; #+NIL is used to comment out forms. Occasionally #+IGNORE is used
@@ -275,6 +288,7 @@
  ;;              particular version of BSD we're intended to run under.)
  ;;   :freebsd = We're intended to run under FreeBSD.
  ;;   :openbsd = We're intended to run under OpenBSD.
+ ;;   :netbsd  = We're intended to run under NetBSD.
  ;;   :sunos   = We're intended to run under Solaris user environment
  ;;              with the SunOS kernel.
  ;;   :osf1    = We're intended to run under Tru64 (aka Digital Unix