Raymond Toy pushed to branch rtoy-15-handle-fpu-exceptions at cmucl / cmucl Commits: 1fab9bf3 by Raymond Toy at 2016-01-13T21:34:39Z Clean up sigfpe-handler; add comments. - - - - - 1 changed file: - src/code/float-trap.lisp Changes: ===================================== src/code/float-trap.lisp ===================================== --- a/src/code/float-trap.lisp +++ b/src/code/float-trap.lisp @@ -312,7 +312,6 @@ ;;; ;;; Signal the appropriate condition when we get a floating-point error. ;;; -(defvar *debug-sigfpe-handler* nil) (defun sigfpe-handler (signal code scp) (declare (ignore signal) (type system-area-pointer scp)) @@ -385,54 +384,53 @@ (error _"SIGFPE with no exceptions currently enabled? (si-code = ~D)" code)))) ;; Cleanup - #+(and darwin ppc) (let* ((new-modes modes) (new-exceptions (logandc2 (ldb float-exceptions-byte new-modes) traps))) - ;; (format t "sigfpe: modes = #B~32,'0b~%" modes) - ;; (format t "sigfpe: new-exc = #B~32,'0b~%" new-exceptions) - (setf (ldb float-exceptions-byte new-modes) new-exceptions) - ;; Clear out all exceptions and save them to the context. - ;; - ;; XXX: Should we just clear out the bits for the traps that are - ;; enabled? If we did that then the accrued exceptions would be - ;; correct. - (setf (ldb float-sticky-bits new-modes) 0) - ;; Clear out the various sticky invalid operation bits too. - ;; - ;; XXX: Should we only do that if the invalid trap is enabled? - (setf (ldb float-invalid-op-1-byte new-modes) 0) - (setf (ldb float-invalid-op-2-byte new-modes) 0) - ;; Clear the FP exception summary bit too. - (setf (ldb float-exceptions-summary-byte new-modes) 0) - ;; (format t "sigfpe: new modes = #B~32,'0b~%" new-modes) - (setf (floating-point-modes) new-modes) - #+nil - (setf (sigcontext-floating-point-modes - (alien:sap-alien scp (* unix:sigcontext))) - new-modes)) - - #+sse2 - (let* ((new-modes modes) - (new-exceptions (logandc2 (ldb float-exceptions-byte new-modes) - traps))) - ;; Clear out the status for any enabled traps. With SSE2, if - ;; the current exception is enabled, the next FP instruction - ;; will cause the exception to be signaled again. Hence, we - ;; need to clear out the exceptions that we are handling here. - (setf (ldb float-exceptions-byte new-modes) new-exceptions) - ;; XXX: This seems not right. Shouldn't we be setting the modes - ;; in the sigcontext instead? This however seems to do what we - ;; want. - - (when *debug-sigfpe-handler* - (format *debug-io* "sigcontext modes: #x~4x (~A)~%" - modes (decode-floating-point-modes modes)) - (format *debug-io* "current modes: #x~4x (~A)~%" - (vm:floating-point-modes) (get-floating-point-modes)) - (format *debug-io* "new modes: #x~x (~A)~%" - new-modes (decode-floating-point-modes new-modes))) - (setf (vm:floating-point-modes) new-modes)))))) + #+(and darwin ppc) + (progn + ;; (format t "sigfpe: modes = #B~32,'0b~%" modes) + ;; (format t "sigfpe: new-exc = #B~32,'0b~%" new-exceptions) + (setf (ldb float-exceptions-byte new-modes) new-exceptions) + ;; Clear out all exceptions. + ;; + ;; XXX: Should we just clear out the bits for the traps that are + ;; enabled? If we did that then the accrued exceptions would be + ;; correct. + (setf (ldb float-sticky-bits new-modes) 0) + ;; Clear out the various sticky invalid operation bits too. + ;; + ;; XXX: Should we only do that if the invalid trap is enabled? + (setf (ldb float-invalid-op-1-byte new-modes) 0) + (setf (ldb float-invalid-op-2-byte new-modes) 0) + ;; Clear the FP exception summary bit too. + (setf (ldb float-exceptions-summary-byte new-modes) 0) + ;; (format t "sigfpe: new modes = #B~32,'0b~%" new-modes) + (setf (floating-point-modes) new-modes)) + + #+sse2 + (progn + ;; Clear out the status for any enabled traps. With SSE2, if + ;; the current exception is enabled, the next FP instruction + ;; will cause the exception to be signaled again. Hence, we + ;; need to clear out the exceptions that we are handling here. + (setf (ldb float-exceptions-byte new-modes) new-exceptions) + #+nil + (progn + (format *debug-io* "sigcontext modes: #x~4x (~A)~%" + modes (decode-floating-point-modes modes)) + (format *debug-io* "current modes: #x~4x (~A)~%" + (vm:floating-point-modes) (get-floating-point-modes)) + (format *debug-io* "new modes: #x~x (~A)~%" + new-modes (decode-floating-point-modes new-modes))) + (setf (vm:floating-point-modes) new-modes)) + + #-(or sse2 (and darwin ppc)) + (progn + ;; Apparently nothing needed for sparc it seems The FPU + ;; state in the signal handler is unchanged and it seems we + ;; don't need to reset it any way when we throw out. + )))))) (macrolet ((with-float-traps (name merge-traps docstring) View it on GitLab: https://gitlab.common-lisp.net/cmucl/cmucl/commit/1fab9bf37ce138dba85e5fb85a...