X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;ds=sidebyside;f=src%2Fcompiler%2Fbackend.lisp;h=cf140b1e644a7f241560dda3e86bf5fbfff258ac;hb=581e3d62de8cb37e13ad9db63e5537c0f962be28;hp=e843d695fbbc51a49ca18a44c27484f250039cfd;hpb=3c65762b927af861c9c8bc416e4cbac9a14ec0c3;p=sbcl.git

diff --git a/src/compiler/backend.lisp b/src/compiler/backend.lisp
index e843d69..cf140b1 100644
--- a/src/compiler/backend.lisp
+++ b/src/compiler/backend.lisp
@@ -107,7 +107,7 @@
 (defvar *backend-t-primitive-type*)
 (declaim (type primitive-type *backend-t-primitive-type*))
 
-;;; a hashtable translating from VOP names to the corresponding VOP-Parse
+;;; a hashtable translating from VOP names to the corresponding VOP-PARSE
 ;;; structures. This information is only used at meta-compile time.
 (defvar *backend-parsed-vops* (make-hash-table :test 'eq))
 (declaim (type hash-table *backend-parsed-vops*))
@@ -151,19 +151,19 @@
 		(eval-when (:compile-toplevel :load-toplevel :execute)
 		  (defparameter *vm-support-routines* ',routines))
 		(defstruct (vm-support-routines (:copier nil))
-		  ,@(mapcar #'(lambda (routine)
-				`(,routine nil :type (or function null)))
+		  ,@(mapcar (lambda (routine)
+			      `(,routine nil :type (or function null)))
 			    routines))
 		,@(mapcar
-		   #'(lambda (name)
-		       `(defun ,name (&rest args)
-			  (apply (or (,(symbolicate "VM-SUPPORT-ROUTINES-"
-						    name)
-				      *backend-support-routines*)
-				     (error "machine-specific support ~S ~
+		   (lambda (name)
+		     `(defun ,name (&rest args)
+			(apply (or (,(symbolicate "VM-SUPPORT-ROUTINES-"
+						  name)
+				    *backend-support-routines*)
+				   (error "machine-specific support ~S ~
 					    routine undefined"
-					    ',name))
-				 args)))
+					  ',name))
+			       args)))
 		   routines))))
 
   (def-vm-support-routines
@@ -180,12 +180,12 @@
     make-call-out-tns
 
     ;; from call.lisp
-    standard-argument-location
+    standard-arg-location
     make-return-pc-passing-location
     make-old-fp-passing-location
     make-old-fp-save-location
     make-return-pc-save-location
-    make-argument-count-location
+    make-arg-count-location
     make-nfp-tn
     make-stack-pointer-tn
     make-number-stack-pointer-tn
@@ -195,7 +195,7 @@
     ;; from nlx.lisp
     make-nlx-sp-tn
     make-dynamic-state-tns
-    make-nlx-entry-argument-start-location
+    make-nlx-entry-arg-start-location
 
     ;; from support.lisp
     generate-call-sequence
@@ -224,12 +224,53 @@
 ;;; the VM support routines
 (defvar *backend-support-routines* (make-vm-support-routines))
 (declaim (type vm-support-routines *backend-support-routines*))
-
-;;; This is a prototype interface to support Christophe Rhodes' new
-;;; (sbcl-0.pre7.57) VOP :GUARD clauses for implementations which
-;;; depend on CPU variants, e.g. the differences between I486,
-;;; Pentium, and Pentium Pro, or the differences between different
-;;; SPARC versions.
+
+;;;; This is a prototype interface to support Christophe Rhodes' new
+;;;; (sbcl-0.pre7.57) VOP :GUARD clauses for implementations which
+;;;; depend on CPU variants, e.g. the differences between I486,
+;;;; Pentium, and Pentium Pro, or the differences between different
+;;;; SPARC versions.
+
+;;;; Christophe Rhodes' longer explanation (cut and pasted
+;;;; from CLiki SBCL internals site 2001-10-12):
+#|
+In CMUCL, the :guard argument to VOPs provided a way of disallowing
+the use of a particular VOP in compiled code. As an example, from the
+SPARC code in CMUCL,
+
+(DEFINE-VOP? (FAST-V8-TRUNCATE/SIGNED=>SIGNED? FAST-SAFE-ARITH-OP?)
+  (:TRANSLATE TRUNCATE?)
+  ...
+  (:GUARD (OR (BACKEND-FEATUREP :SPARC-V8)
+              (AND (BACKEND-FEATUREP :SPARC-V9)
+                   (NOT (BACKEND-FEATUREP :SPARC-64)))))
+  ...)
+
+and at the IR2 translation stage, the function #'`(LAMBDA () ,GUARD) would be called. 
+
+Until SBCL-0.7pre57, this is translated as 
+  (:GUARD #!+(OR :SPARC-V8 (AND :SPARC-V9 (NOT :SPARC-64))) T
+          #!-(OR :SPARC-V8 (AND :SPARC-V9 (NOT :SPARC-64))) NIL)
+which means that whether this VOP will ever be used is determined at
+compiler compile-time depending on the contents of
+*SHEBANG-FEATURES*?.
+
+As of SBCL-0.7pre57, a new special variable,
+SB-C:*BACKEND-SUBFEATURES*?, is introduced. As of that version, only
+VOPs translating %log1p? query it, and :PENTIUM-STYLE-FYL2XP1 is the
+only useful value to be pushed onto that list, for x86. This is not
+yet an ideal interface, but it does allow for compile-time
+conditionalization.
+|#
+
+;;; The default value of NIL means use only unguarded VOPs. The
+;;; initial value is customizeable via
+;;; customize-backend-subfeatures.lisp
+(defvar *backend-subfeatures* '#.sb-cold:*shebang-backend-subfeatures*)
+
+;;; possible *BACKEND-SUBFEATURES* values:
 ;;;
-;;; The default value of NIL means use only unguarded VOPs.
-(defvar *backend-subfeatures* nil)
+;;; :PENTIUM-STYLE-FYL2XP1 is a useful value for x86 SBCLs to have on
+;;; SB-C:*BACKEND-SUBFEATURES*?; it enables the use of the
+;;; %flog1p-pentium? VOP rather than the %flog1p? VOP, which is a few
+;;; instructions longer.