X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;f=src%2Fruntime%2Finterrupt.c;h=94b2de85dac4fd03f2148c25b0124c346a7f4bbf;hb=4fc9d21ae1d8a6a2f8ff70f589d5da103203de13;hp=616bc78269a19e71a233089763d16eb6ea83f328;hpb=5dc28680e9cb2d598da02aed512aa49ea81fdade;p=sbcl.git

diff --git a/src/runtime/interrupt.c b/src/runtime/interrupt.c
index 616bc78..94b2de8 100644
--- a/src/runtime/interrupt.c
+++ b/src/runtime/interrupt.c
@@ -220,7 +220,7 @@ void
 interrupt_internal_error(int signal, siginfo_t *info, os_context_t *context,
 			 boolean continuable)
 {
-    lispobj context_sap;
+    lispobj context_sap = 0;
 
     fake_foreign_function_call(context);
 
@@ -257,7 +257,9 @@ interrupt_internal_error(int signal, siginfo_t *info, os_context_t *context,
 void
 interrupt_handle_pending(os_context_t *context)
 {
+#ifndef __i386__
     boolean were_in_lisp = !foreign_function_call_active;
+#endif
 
     SetSymbolValue(INTERRUPT_PENDING, NIL);
 
@@ -302,12 +304,27 @@ void
 interrupt_handle_now(int signal, siginfo_t *info, void *void_context)
 {
     os_context_t *context = (os_context_t*)void_context;
-    int were_in_lisp;
+#ifndef __i386__
+    boolean were_in_lisp;
+#endif
     union interrupt_handler handler;
 
-#ifdef __linux__
-    SET_FPU_CONTROL_WORD(context->__fpregs_mem.cw);
-#endif
+    /* FIXME: The CMU CL we forked off of had this Linux-only
+     * operation here. Newer CMU CLs (e.g. 18c) have hairier
+     * Linux/i386-only logic here. SBCL seems to be more reliable
+     * without anything here. However, if we start supporting code
+     * which sets the rounding mode, then we may want to do something
+     * special to force the rounding mode back to some standard value
+     * here, so that ISRs can have a standard environment. (OTOH, if
+     * rounding modes are under user control, then perhaps we should
+     * leave this up to the user.)
+     *
+     * In the absence of a test case to show that this is really a
+     * problem, we just suppress this code completely (just like the
+     * parallel code in maybe_now_maybe_later).
+     * #ifdef __linux__
+     *    SET_FPU_CONTROL_WORD(context->__fpregs_mem.cw);
+     * #endif */
 
     handler = interrupt_handlers[signal];
 
@@ -315,8 +332,8 @@ interrupt_handle_now(int signal, siginfo_t *info, void *void_context)
 	return;
     }
 
-    were_in_lisp = !foreign_function_call_active;
 #ifndef __i386__
+    were_in_lisp = !foreign_function_call_active;
     if (were_in_lisp)
 #endif
     {
@@ -381,14 +398,14 @@ maybe_now_maybe_later(int signal, siginfo_t *info, void *void_context)
 
     /* FIXME: See Debian cmucl 2.4.17, and mail from DTC on the CMU CL
      * mailing list 23 Oct 1999, for changes in FPU handling at
-     * interrupt time which should be ported into SBCL. 
+     * interrupt time which should be ported into SBCL. Also see the
+     * analogous logic at the head of interrupt_handle_now for
+     * more related FIXME stuff. 
      *
-     * (Is this related to the way that it seems that if we do decide
-     * to handle the interrupt later, we've now screwed up the FPU
-     * control word?) */
-#ifdef __linux__
-    SET_FPU_CONTROL_WORD(context->__fpregs_mem.cw);
-#endif
+     * For now, we just suppress this code completely.
+     * #ifdef __linux__
+     *    SET_FPU_CONTROL_WORD(context->__fpregs_mem.cw);
+     * #endif */
 
     if (SymbolValue(INTERRUPTS_ENABLED) == NIL) {