X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;ds=sidebyside;f=src%2Fcompiler%2Fx86%2Fsap.lisp;h=b9e6bcdacc72e7a694219b60bf3c83231fb6d9a6;hb=f17811c866c0412da17d3ee94f11cf38783301f7;hp=052b427e58e990c77b349edaa237a1e34eef431d;hpb=cea4896b2482b7b2b429c1631d774b4cfbc0efba;p=sbcl.git

diff --git a/src/compiler/x86/sap.lisp b/src/compiler/x86/sap.lisp
index 052b427..b9e6bcd 100644
--- a/src/compiler/x86/sap.lisp
+++ b/src/compiler/x86/sap.lisp
@@ -76,6 +76,12 @@
 
 ;;;; SAP-INT and INT-SAP
 
+;;; The function SAP-INT is used to generate an integer corresponding
+;;; to the system area pointer, suitable for passing to the kernel
+;;; interfaces (which want all addresses specified as integers). The
+;;; function INT-SAP is used to do the opposite conversion. The
+;;; integer representation of a SAP is the byte offset of the SAP from
+;;; the start of the address space.
 (define-vop (sap-int)
   (:args (sap :scs (sap-reg) :target int))
   (:arg-types system-area-pointer)
@@ -85,7 +91,6 @@
   (:policy :fast-safe)
   (:generator 1
     (move int sap)))
-
 (define-vop (int-sap)
   (:args (int :scs (unsigned-reg) :target sap))
   (:arg-types unsigned-num)