Changeset 13940

Timestamp:

Jul 7, 2010, 8:16:23 PM (14 years ago)

Author:

R. Matthew Emerson

Message:

Only avoid saving/restoring the MXCSR around FF calls on x8664,
at least for now.

Location:

branches/rme-fpe/lisp-kernel

Files:

• x86-exceptions.c (modified) (2 diffs)
• x86-spentry32.s (modified) (4 diffs)

branches/rme-fpe/lisp-kernel/x86-exceptions.c

@@ -955 +955 @@
 
   if (old_valence == TCR_STATE_FOREIGN) {
+#ifdef X8632
+    return false;
+#else
     /* We got a floating point exception in foreign code.  Set a flag
        in the TCR to indicate this, and resume with FP exceptions
@@ -971 +974 @@
     xpMXCSR(xp) |= MXCSR_CONTROL_MASK;
     return true;
-  } else if ((fulltag_of(cmain) == fulltag_misc) &&
+#endif
+  }
+
+  if ((fulltag_of(cmain) == fulltag_misc) &&
              (header_subtag(header_of(cmain)) == subtag_macptr)) {
     xcf = create_exception_callback_frame(xp, tcr);

branches/rme-fpe/lisp-kernel/x86-spentry32.s

@@ -4184 +4184 @@
         __(popl rcontext(tcr.save_eflags))
         __(cld)        
+        __(stmxcsr rcontext(tcr.lisp_mxcsr))
         __(emms)
+        __(ldmxcsr rcontext(tcr.foreign_mxcsr))
         __(movl (%esp),%ebp)
 LocalLabelPrefix`'ffcall_setup:
@@ -4213 +4215 @@
         __(clr %fn)
         __(pxor %fpzero,%fpzero)
-        /* If we got a floating-point exception during the ff-call,
-           our handler will have set a flag, preserved lisp's MXCSR,
-           and resumed execution with fp exceptions masked. */
-        __(btrl $TCR_FLAG_BIT_FOREIGN_FPE,rcontext(tcr.flags))
-        __(jnc 1f)
         __(cmpb $0,C(bogus_fp_exceptions))
         __(je 0f)
@@ -4225 +4222 @@
         __ifdef(`SSE2_MATH_LIB')
         __(stmxcsr rcontext(tcr.ffi_exception))
-        __(ldmxcsr rcontext(tcr.lisp_mxcsr)) /* preserved by the handler */
         __else
         __(fnstsw rcontext(tcr.ffi_exception))
@@ -4239 +4235 @@
         __(pop %arg_y)           
         __(pop %temp1) 
+        __(ldmxcsr rcontext(tcr.lisp_mxcsr))
         __(check_pending_interrupt(%temp0))
         __(pop %temp0)