1.0.18.2: more conservative interval artihmetic

[sbcl.git] / src / compiler / generic / early-vm.lisp

diff --git a/src/compiler/generic/early-vm.lisp b/src/compiler/generic/early-vm.lisp
index 1e7ec1c..57c2d9d 100644 (file)
--- a/src/compiler/generic/early-vm.lisp
+++ b/src/compiler/generic/early-vm.lisp
@@ -25,13 +25,19 @@
 ;;; the bit width of positive fixnums
 (def!constant n-positive-fixnum-bits (- n-word-bits n-fixnum-tag-bits 1))
 
+;;; the number of bits to shift between word addresses and byte addresses
+(def!constant word-shift (1- (integer-length (/ n-word-bits n-byte-bits))))
+
+;;; the number of bytes in a word
+(def!constant n-word-bytes (/ n-word-bits n-byte-bits))
+
 ;;; the number of bits used in the header word of a data block to store
 ;;; the type
 (def!constant n-widetag-bits 8)
 ;;; a mask to extract the type from a data block header word
 (def!constant widetag-mask (1- (ash 1 n-widetag-bits)))
 
-(def!constant sb!xc:most-positive-fixnum  
+(def!constant sb!xc:most-positive-fixnum
     (1- (ash 1 (- n-word-bits n-lowtag-bits)))
   #!+sb-doc
   "the fixnum closest in value to positive infinity")
@@ -39,3 +45,12 @@
     (ash -1 (- n-word-bits n-lowtag-bits))
   #!+sb-doc
   "the fixnum closest in value to negative infinity")
+
+(def!constant most-positive-exactly-single-float-fixnum
+  (min #xffffff most-positive-fixnum))
+(def!constant most-negative-exactly-single-float-fixnum
+  (max #x-ffffff most-negative-fixnum))
+(def!constant most-positive-exactly-double-float-fixnum
+  (min #x1fffffffffffff most-positive-fixnum))
+(def!constant most-negative-exactly-double-float-fixnum
+  (max #x-1fffffffffffff most-negative-fixnum))