MISC.556 by falling into gdb with
fatal error encountered in SBCL pid 2827: Unhandled SIGILL
unless the MISC.556 test is commented out.
+
+Analysis: + and a number of other arithmetic functions exhibit the
+same behaviour. Here's the underlying problem: On x86 we perform
+single-float + integer normally using double-precision, and then
+coerce the result back to single-float. (The FILD instruction always
+gives us a double-float, and unless we do MOVE-FROM-SINGLE it remains
+one. Or so it seems to me, and that would also explain the observed
+behaviour below.)
+
+During IR1 we derive the types for both
+
+ (+ <single> <integer>) ; uses double-precision
+ (+ <single> (FLOAT <integer> <single>)) ; uses single-precision
+
+and get a mismatch for a number of unlucky arguments. This leads to
+derived result type NIL, and ends up flushing the whole whole
+operation -- and finally we generate code without a return sequence,
+and fall through to whatever.
+
+The use of double-precision in the first case appears to be an
+(un)happy accident -- interval arithmetic gives us the
+double-precision result because that's what the backend does.
+
+ (+ 8172.0 (coerce -95195347 'single-float)) ; => -9.518717e7
+ (+ 8172.0 -95195347) ; => -9.5187176e7
+ (coerce (+ 8172.0 (coerce -95195347 'double-float)) 'single-float)
+ ; => -9.5187176e7
+
+Which should be fixed, the IR1, or the backend?
+
+421: READ-CHAR-NO-HANG misbehaviour on Windows Console:
+
+ It seems that on Windows READ-CHAR-NO-HANG hangs if the user
+ has pressed a key, but not yet enter (ie. SYSREAD-MAY-BLOCK-P
+ seems to lie if the OS is buffering input for us on Console.)
+
+ reported by Elliot Slaughter on sbcl-devel 2008/1/10.
projects / sbcl.git / blobdiff