FPU: Update committed FPSCR value correctly

The committed FPSCR is updated in the cycle where an FPU instruction
signals completion.  Since we update the FPRF field in the FPSCR in
that same cycle, the value put into r.comm_fpscr needs to include
the new FPRF value.  Otherwise, a subsequent flush (for example,
due to the following instruction being an illegal instruction that
has to be emulated) will drop the FPSCR update.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>

Author: paulusmack

fpu.vhdl

@@ -1077,7 +1077,6 @@ begin
             v.writing_fpr := '0';
             v.writing_cr := '0';
             v.writing_xer := '0';
-            v.comm_fpscr := r.fpscr;
             v.illegal := '0';
         end if;
 
@@ -3728,6 +3727,10 @@ begin
             v.fpscr(FPSCR_FX) := '1';
         end if;
 
+        if r.complete = '1' or r.do_intr = '1' then
+            v.comm_fpscr := v.fpscr;
+        end if;
+
         if v.instr_done = '1' then
             if r.state /= IDLE then
                 v.state := IDLE;