+;;;; -*- Lisp -*-
+
;;;; tags which are set during the build process and which end up in
;;;; CL:*FEATURES* in the target SBCL, plus some comments about other
;;;; CL:*FEATURES* tags which have special meaning to SBCL or which
;; our standard
:ansi-cl :common-lisp
;; FIXME: Isn't there a :x3jsomething feature which we should set too?
+ ;; No. CLHS says ":x3j13 [...] A conforming implementation might or
+ ;; might not contain such a feature." -- CSR, 2002-02-21
;; our dialect
:sbcl
;; Douglas Thomas Crosher's conservative generational GC (the only one
- ;; we currently support for X86)
- :gencgc
+ ;; we currently support for X86).
+ ;; :gencgc used to be here; CSR moved it into
+ ;; local-target-features.lisp-expr via make-config.sh, as alpha,
+ ;; sparc and ppc ports don't currently support it. -- CSR, 2002-02-21
;; We're running under a UNIX. This is sort of redundant, and it was also
;; sort of redundant under CMU CL, which we inherited it from: neither SBCL
;; the executable I'm running.
:sb-doc
- ;; Do regression and other tests when building the system. You
- ;; might or might not want this if you're not a developer,
- ;; depending on how paranoid you are. You probably do want it if
- ;; you are a developer.
+ ;; Do regression and other tests when building the system. You might
+ ;; or might not want this if you're not a developer, depending on how
+ ;; paranoid you are. You probably do want it if you are a developer.
+ ;; This test does not affect the target system (in much the same way
+ ;; as :sb-after-xc-core, below).
:sb-test
;; Make more debugging information available (for debugging SBCL
;; 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) you shouldn't need this.
+ ;; 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
;; whether the build process produces an after-xc.core file. This
- ;; can be useful for shortening the edit/compile/debug cycle if
- ;; you're messing around with low-level internals of the system,
- ;; as in slam.sh. Otherwise you don't need it.
+ ;; can be useful for shortening the edit/compile/debug cycle when
+ ;; you modify SBCL's own source code, as in slam.sh. Otherwise
+ ;; you don't need it.
; :sb-after-xc-core
;; Enable extra debugging output in the assem.lisp assembler/scheduler
; :high-security
; :high-security-support
- ;; multiprocessing 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
+ ;; low-level thread primitives support
+ ;;
+ ;; 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
+
;; 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
;; 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
;; any Intel 386 or better, or compatibles like the AMD K6 or K7
;; :alpha
;; DEC/Compaq Alpha CPU
- ;; (No other CPUs are supported by SBCL as of 0.6.12.15, but SPARC or
- ;; PowerPC support could be ported from CMU CL if anyone is
- ;; sufficiently motivated to do so, or if you're *really* motivated,
- ;; you could write a port from scratch for a new CPU architecture.)
+ ;; :sparc
+ ;; any Sun UltraSPARC (possibly also non-Ultras -- currently untested)
+ ;; :ppc
+ ;; any PowerPC CPU
+ ;; :hppa
+ ;; any PA-RISC CPU
+ ;; :mips
+ ;; any MIPS CPU (in little-endian mode with :little-endian -- currently
+ ;; untested)
+ ;;
;; (CMU CL also had a :pentium feature, which affected the definition
- ;; of some floating point vops. It was present but not enabled or
- ;; documented in the CMU CL code that SBCL is derived from, and is
- ;; present but stale in SBCL as of 0.6.12.)
+ ;; of some floating point vops. It was present but not enabled or
+ ;; documented in the CMU CL code that SBCL is derived from, and has
+ ;; now been moved to the backend-subfeatures mechanism.)
+ ;;
+ ;; properties derived from the machine architecture
+ ;; :control-stack-grows-downward-not-upward
+ ;; On the X86, the Lisp control stack grows downward. On the
+ ;; other supported CPU architectures as of sbcl-0.7.1.40, the
+ ;; system stack grows upward.
+ ;; Note that there are other stack-related differences between the
+ ;; X86 port and the other ports. E.g. on the X86, the Lisp control
+ ;; stack coincides with the C stack, meaning that on the X86 there's
+ ;; stuff on the control stack that the Lisp-level debugger doesn't
+ ;; understand very well. As of sbcl-0.7.1.40 things like that are
+ ;; just parameterized by #!+X86, but it'd probably be better to
+ ;; use new flags like :CONTROL-STACK-CONTAINS-C-STACK.
;;
;; operating system features:
;; :linux = We're intended to run under some version of Linux.
;; is not exclusive with the features which indicate which
;; 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 FreeBSD.
- ;; (No others are supported by SBCL as of 0.6.7, but :hpux or
- ;; :solaris support could be ported from CMU CL if anyone is
- ;; sufficiently motivated to do so, and it'd even be possible,
- ;; though harder, to port the system to Microsoft Windows.)
+ ;; :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
+ ;; aka OSF/1).
+ ;; (No others are supported by SBCL as of 0.7.5, but :hpux or :irix
+ ;; support could be ported from CMU CL if anyone is sufficiently
+ ;; motivated to do so, and it'd even be possible, though harder, to
+ ;; port the system to Microsoft Windows or MacOS X.)
)
projects / sbcl.git / blobdiff