From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53224) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YOYRL-0000e1-OJ for qemu-devel@nongnu.org; Thu, 19 Feb 2015 16:15:20 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YOYRK-0007MO-48 for qemu-devel@nongnu.org; Thu, 19 Feb 2015 16:15:19 -0500 Received: from mail-qa0-x230.google.com ([2607:f8b0:400d:c00::230]:34947) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YOYRK-0007MG-0R for qemu-devel@nongnu.org; Thu, 19 Feb 2015 16:15:18 -0500 Received: by mail-qa0-f48.google.com with SMTP id dc16so8503049qab.7 for ; Thu, 19 Feb 2015 13:15:17 -0800 (PST) Sender: Richard Henderson From: Richard Henderson Date: Thu, 19 Feb 2015 13:14:28 -0800 Message-Id: <1424380469-20138-11-git-send-email-rth@twiddle.net> In-Reply-To: <1424380469-20138-1-git-send-email-rth@twiddle.net> References: <1424380469-20138-1-git-send-email-rth@twiddle.net> Subject: [Qemu-devel] [PATCH 10/11] target-arm: Implement fccmp branchless List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: peter.maydell@linaro.org Signed-off-by: Richard Henderson --- target-arm/translate-a64.c | 50 +++++++++++++++++++++++++++------------------- 1 file changed, 29 insertions(+), 21 deletions(-) diff --git a/target-arm/translate-a64.c b/target-arm/translate-a64.c index 8171a1f..5539ae3 100644 --- a/target-arm/translate-a64.c +++ b/target-arm/translate-a64.c @@ -4128,11 +4128,11 @@ static void disas_data_proc_reg(DisasContext *s, uint32_t insn) } } -static void handle_fp_compare(DisasContext *s, bool is_double, - unsigned int rn, unsigned int rm, - bool cmp_with_zero, bool signal_all_nans) +static void handle_fp_compare_1(DisasContext *s, TCGv_i64 tcg_flags, + bool is_double, unsigned int rn, + unsigned int rm, bool cmp_with_zero, + bool signal_all_nans) { - TCGv_i64 tcg_flags = tcg_temp_new_i64(); TCGv_ptr fpst = get_fpstatus_ptr(); if (is_double) { @@ -4170,7 +4170,16 @@ static void handle_fp_compare(DisasContext *s, bool is_double, } tcg_temp_free_ptr(fpst); +} +static void handle_fp_compare(DisasContext *s, bool is_double, + unsigned int rn, unsigned int rm, + bool cmp_with_zero, bool signal_all_nans) +{ + TCGv_i64 tcg_flags = tcg_temp_new_i64(); + + handle_fp_compare_1(s, tcg_flags, is_double, rn, rm, + cmp_with_zero, signal_all_nans); gen_set_nzcv(tcg_flags); tcg_temp_free_i64(tcg_flags); @@ -4215,8 +4224,8 @@ static void disas_fp_compare(DisasContext *s, uint32_t insn) static void disas_fp_ccomp(DisasContext *s, uint32_t insn) { unsigned int mos, type, rm, cond, rn, op, nzcv; - TCGv_i64 tcg_flags; - TCGLabel *label_continue = NULL; + TCGv_i64 t_flags, t_zero, t_nzcv; + DisasCompare c; mos = extract32(insn, 29, 3); type = extract32(insn, 22, 2); /* 0 = single, 1 = double */ @@ -4235,23 +4244,22 @@ static void disas_fp_ccomp(DisasContext *s, uint32_t insn) return; } - if (cond < 0x0e) { /* not always */ - TCGLabel *label_match = gen_new_label(); - label_continue = gen_new_label(); - arm_gen_test_cc(cond, label_match); - /* nomatch: */ - tcg_flags = tcg_const_i64(nzcv << 28); - gen_set_nzcv(tcg_flags); - tcg_temp_free_i64(tcg_flags); - tcg_gen_br(label_continue); - gen_set_label(label_match); - } + /* Perform the new compare, but don't write the result back to flags. */ + t_flags = tcg_temp_new_i64(); + handle_fp_compare_1(s, t_flags, type, rn, rm, false, op); - handle_fp_compare(s, type, rn, rm, false, op); + /* If the condition is false, force the flags to #nzcv. */ + arm_test_cc(&c, cond); + t_zero = tcg_const_i64(0); + t_nzcv = tcg_const_i64(nzcv << 28); + tcg_gen_movcond_i64(c.cond, t_flags, c.value, t_zero, t_flags, t_nzcv); + tcg_temp_free_i64(t_zero); + tcg_temp_free_i64(t_nzcv); + arm_free_cc(&c); - if (cond < 0x0e) { - gen_set_label(label_continue); - } + /* Write back the new flags. */ + gen_set_nzcv(t_flags); + tcg_temp_free_i64(t_flags); } /* copy src FP register to dst FP register; type specifies single or double */ -- 2.1.0