1.0.29.54: Inline unboxed constants on x86[-64]

[sbcl.git] / base-target-features.lisp-expr

diff --git a/base-target-features.lisp-expr b/base-target-features.lisp-expr
index f389507..50b732e 100644 (file)
--- a/base-target-features.lisp-expr
+++ b/base-target-features.lisp-expr
@@ -167,6 +167,42 @@
  ;;
  ; :complex-float-vops
 
+ ;; Enabled automatically for platforms which implement VOPs for EQL
+ ;; of single and double floats.
+ ;;
+ ; :float-eql-vops
+
+ ;; Enabled automatically for platform that can implement inline constants.
+ ;;
+ ;; Such platform must implement 5 functions, in SB!VM:
+ ;; * canonicalize-inline-constant: converts a constant descriptor (list) into
+ ;;    a canonical description, to be used as a key in an EQUAL hash table
+ ;;    and to guide the generation of the constant itself.
+ ;; * inline-constant-value: given a canonical constant descriptor, computes
+ ;;    two values:
+ ;;     1. A label that will be used to emit the constant (usually a
+ ;;         sb!assem:label)
+ ;;     2. A value that will be returned to code generators referring to
+ ;;         the constant (on x86oids, an EA object)
+ ;; * sort-inline-constants: Receives a vector of unique constants;
+ ;;    the car of each entry is the constant descriptor, and the cdr the
+ ;;    corresponding label. Destructively returns a vector of constants
+ ;;    sorted in emission order. It could actually perform arbitrary
+ ;;    modifications to the vector, e.g. to fuse constants of different
+ ;;    size.
+ ;; * emit-constant-segment-header: receives the vector of sorted constants
+ ;;    and a flag (true iff speed > space). Expected to emit padding
+ ;;    of some sort between the ELSEWHERE segment and the constants, or some
+ ;;    metadata.
+ ;; * emit-inline-constant: receives a constant descriptor and its associated
+ ;;    label. Emits the constant.
+ ;;
+ ;; Implementing this features lets VOP generators use sb!c:register-inline-constant
+ ;; to get handles (as returned by sb!vm:inline-constant-value) from constant
+ ;; descriptors.
+ ;;
+ ; :inline-constants
+
  ;; Peter Van Eynde's increase-bulletproofness code for CMU CL
  ;;
  ;; Some of the code which was #+high-security before the fork has now