target-ppc: Fix and enable fri[mnpz]

The fri* series of instructions was introduced prior to ISA 2.06 and
is supported on Power7 and Power8 hardware.  However, the instruction
is still considered illegal in the P7 and P8 QEMU emulation models.
This patch enables these instructions for the P7 and P8 machines.

Also, the existing helper is modified to correctly handle some of
the boundary cases (NaNs and the inexact flag).

Signed-off-by: Tom Musta <tommusta@gmail.com>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Alexander Graf <agraf@suse.de>

1 files changed, 11 insertions, 7 deletions

diff --git a/target-ppc/fpu_helper.c b/target-ppc/fpu_helper.c
index eb56082c94..87ff60fc62 100644
--- a/target-ppc/fpu_helper.c
+++ b/target-ppc/fpu_helper.c
@@ -669,24 +669,28 @@ static inline uint64_t do_fri(CPUPPCState *env, uint64_t arg,
 
     if (unlikely(float64_is_signaling_nan(farg.d))) {
         /* sNaN round */
-        farg.ll = fload_invalid_op_excp(env, POWERPC_EXCP_FP_VXSNAN |
-                                        POWERPC_EXCP_FP_VXCVI, 1);
-    } else if (unlikely(float64_is_quiet_nan(farg.d) ||
-                        float64_is_infinity(farg.d))) {
-        /* qNan / infinity round */
-        farg.ll = fload_invalid_op_excp(env, POWERPC_EXCP_FP_VXCVI, 1);
+        fload_invalid_op_excp(env, POWERPC_EXCP_FP_VXSNAN, 1);
+        farg.ll = arg | 0x0008000000000000ul;
     } else {
+        int inexact = get_float_exception_flags(&env->fp_status) &
+                      float_flag_inexact;
         set_float_rounding_mode(rounding_mode, &env->fp_status);
         farg.ll = float64_round_to_int(farg.d, &env->fp_status);
         /* Restore rounding mode from FPSCR */
         fpscr_set_rounding_mode(env);
+
+        /* fri* does not set FPSCR[XX] */
+        if (!inexact) {
+            env->fp_status.float_exception_flags &= ~float_flag_inexact;
+        }
     }
+    helper_float_check_status(env);
     return farg.ll;
 }
 
 uint64_t helper_frin(CPUPPCState *env, uint64_t arg)
 {
-    return do_fri(env, arg, float_round_nearest_even);
+    return do_fri(env, arg, float_round_ties_away);
 }
 
 uint64_t helper_friz(CPUPPCState *env, uint64_t arg)