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From: "Bruno Larsen (billionai)" <bruno.larsen@eldorado.org.br>
To: qemu-devel@nongnu.org
Cc: farosas@linux.ibm.com, richard.henderson@linaro.org,
	luis.pires@eldorado.org.br, lucas.araujo@eldorado.org.br,
	fernando.valle@eldorado.org.br, qemu-ppc@nongnu.org,
	matheus.ferst@eldorado.org.br, david@gibson.dropbear.id.au
Subject: [PATCH v3 3/9] target/ppc: reduce usage of fpscr_set_rounding_mode
Date: Fri, 21 May 2021 17:17:53 -0300	[thread overview]
Message-ID: <20210521201759.85475-4-bruno.larsen@eldorado.org.br> (raw)
In-Reply-To: <20210521201759.85475-1-bruno.larsen@eldorado.org.br>

It is preferable to store the current rounding mode and retore from that
than recalculating from fpscr, so we changed the behavior of do_fri and
VSX_ROUND to do it like that.

Suggested-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Bruno Larsen (billionai) <bruno.larsen@eldorado.org.br>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/ppc/fpu_helper.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/target/ppc/fpu_helper.c b/target/ppc/fpu_helper.c
index 44315fca0b..a4a283df2b 100644
--- a/target/ppc/fpu_helper.c
+++ b/target/ppc/fpu_helper.c
@@ -822,6 +822,7 @@ static inline uint64_t do_fri(CPUPPCState *env, uint64_t arg,
                               int rounding_mode)
 {
     CPU_DoubleU farg;
+    FloatRoundMode old_rounding_mode = get_float_rounding_mode(&env->fp_status);
 
     farg.ll = arg;
 
@@ -834,8 +835,7 @@ static inline uint64_t do_fri(CPUPPCState *env, uint64_t arg,
                       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);
+        set_float_rounding_mode(old_rounding_mode, &env->fp_status);
 
         /* fri* does not set FPSCR[XX] */
         if (!inexact) {
@@ -3136,8 +3136,10 @@ void helper_##op(CPUPPCState *env, ppc_vsr_t *xt, ppc_vsr_t *xb)       \
 {                                                                      \
     ppc_vsr_t t = *xt;                                                 \
     int i;                                                             \
+    FloatRoundMode curr_rounding_mode;                                 \
                                                                        \
     if (rmode != FLOAT_ROUND_CURRENT) {                                \
+        curr_rounding_mode = get_float_rounding_mode(&env->fp_status); \
         set_float_rounding_mode(rmode, &env->fp_status);               \
     }                                                                  \
                                                                        \
@@ -3160,7 +3162,7 @@ void helper_##op(CPUPPCState *env, ppc_vsr_t *xt, ppc_vsr_t *xb)       \
      * mode from FPSCR                                                 \
      */                                                                \
     if (rmode != FLOAT_ROUND_CURRENT) {                                \
-        fpscr_set_rounding_mode(env);                                  \
+        set_float_rounding_mode(curr_rounding_mode, &env->fp_status);  \
         env->fp_status.float_exception_flags &= ~float_flag_inexact;   \
     }                                                                  \
                                                                        \
-- 
2.17.1



  parent reply	other threads:[~2021-05-21 20:24 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-21 20:17 [PATCH v3 0/9] target/ppc: add support to disable-tcg Bruno Larsen (billionai)
2021-05-21 20:17 ` [PATCH v3 1/9] target/ppc: cleaned error_report from ppc_store_sdr1 Bruno Larsen (billionai)
2021-05-24  2:36   ` David Gibson
2021-05-21 20:17 ` [PATCH v3 2/9] target/ppc: moved ppc_store_lpcr and ppc_store_msr to cpu.c Bruno Larsen (billionai)
2021-05-24  2:37   ` David Gibson
2021-05-21 20:17 ` Bruno Larsen (billionai) [this message]
2021-05-24  2:38   ` [PATCH v3 3/9] target/ppc: reduce usage of fpscr_set_rounding_mode David Gibson
2021-05-21 20:17 ` [PATCH v3 4/9] target/ppc: overhauled and moved logic of storing fpscr Bruno Larsen (billionai)
2021-05-24  2:41   ` David Gibson
2021-05-25  2:01   ` Richard Henderson
2021-05-25  3:15     ` David Gibson
2021-05-21 20:17 ` [PATCH v3 5/9] target/ppc: removed unnecessary inclusion of helper-proto.h Bruno Larsen (billionai)
2021-05-24  2:41   ` David Gibson
2021-05-21 20:17 ` [PATCH v3 6/9] target/ppc: moved ppc_cpu_do_interrupt to cpu.c Bruno Larsen (billionai)
2021-05-24  2:57   ` David Gibson
2021-05-25  2:11   ` Richard Henderson
2021-05-21 20:17 ` [PATCH v3 7/9] target/ppc: Added options to disable many TCG-only functions Bruno Larsen (billionai)
2021-05-24  3:01   ` David Gibson
2021-05-21 20:17 ` [PATCH v3 8/9] target/ppc: created tcg-stub.c file Bruno Larsen (billionai)
2021-05-24  3:02   ` David Gibson
2021-05-24 12:54     ` Bruno Piazera Larsen
2021-05-21 20:17 ` [PATCH v3 9/9] target/ppc: updated meson.build to support disable-tcg Bruno Larsen (billionai)
2021-05-25  2:13   ` Richard Henderson

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