From 4d1e3fe83816eff4c0b914b7e2a008c81e73f682 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=B6rg=20F=2E=20Wittenberger?=
 <address@hidden>
Date: Wed, 19 Dec 2018 17:52:15 +0100
Subject: [PATCH] Use dedicated thread instead of forcing primordial for
 signals.

Note: force-primordial is a misnomer now.  Left alone to keep tests
working.  TBD: Hide the identifyer and remove those tests.
---
 scheduler.scm | 27 +++++++++++++++++++++++----
 1 file changed, 23 insertions(+), 4 deletions(-)

diff --git a/scheduler.scm b/scheduler.scm
index df4db928..63bced60 100644
--- a/scheduler.scm
+++ b/scheduler.scm
@@ -233,10 +233,29 @@ EOF
 		[(eq? (##sys#slot nt 3) 'ready) (switch nt)]
 		[else (loop2)] ) ) ) ) ) )
 
-(define (##sys#force-primordial)
-  (dbg "primordial thread forced due to interrupt")
-  (##sys#setislot ##sys#primordial-thread 13 #f)
-  (##sys#thread-unblock! ##sys#primordial-thread) )
+(define ##sys#force-primordial
+  (let* ((thread #f)
+	 (install!
+	  (lambda ()
+	    (set! thread
+		  (##sys#make-thread
+		   (lambda ()
+		     (let loop ()
+		       ;; inline from (thread-suspend! (current-thread))
+		       (##sys#setslot thread 3 'suspended)
+		       (##sys#call-with-current-continuation
+			(lambda (return)
+			  (##sys#setslot thread 1 (lambda () (return (##core#undefined))))
+			  (##sys#schedule) ) )
+		       (loop)))
+		   'suspended 'signal-handler 10)))))
+    (install!)
+    (lambda ()
+      (dbg "signal thread forced due to interrupt")
+      ;; inline from thread-resume!
+      (unless (eq? (##sys#slot thread 3) 'suspended) (install!))
+      (##sys#setslot thread 3 'ready)
+      (##sys#add-to-ready-queue thread))) )
 
 (define ready-queue-head '())
 (define ready-queue-tail '())
-- 
2.11.0