From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:36359) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VR2Br-0005GP-J4 for qemu-devel@nongnu.org; Tue, 01 Oct 2013 11:48:53 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VR2Bl-0001TP-EW for qemu-devel@nongnu.org; Tue, 01 Oct 2013 11:48:47 -0400 Received: from cantor2.suse.de ([195.135.220.15]:34272 helo=mx2.suse.de) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VR2Bl-0001TE-5n for qemu-devel@nongnu.org; Tue, 01 Oct 2013 11:48:41 -0400 Message-ID: <524AEED6.4050908@suse.de> Date: Tue, 01 Oct 2013 17:48:38 +0200 From: Alexander Graf MIME-Version: 1.0 References: <1379945085-29086-1-git-send-email-rth@twiddle.net> <1379945085-29086-2-git-send-email-rth@twiddle.net> <5249BD03.60608@suse.de> <5249CDDD.3080100@twiddle.net> In-Reply-To: <5249CDDD.3080100@twiddle.net> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 01/10] target-s390: Move facilities bits to env List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Richard Henderson Cc: qemu-devel@nongnu.org, =?ISO-8859-1?Q?Andreas_F=E4rber?= On 09/30/2013 09:15 PM, Richard Henderson wrote: > On 09/30/2013 11:03 AM, Alexander Graf wrote: >> On 09/23/2013 04:04 PM, Richard Henderson wrote: >>> Rather than simply hard-coding them in STFL instruction. >>> >>> Signed-off-by: Richard Henderson >>> --- >>> target-s390x/cpu.c | 3 +++ >>> target-s390x/cpu.h | 1 + >>> target-s390x/translate.c | 10 +++++----- >>> 3 files changed, 9 insertions(+), 5 deletions(-) >>> >>> diff --git a/target-s390x/cpu.c b/target-s390x/cpu.c >>> index 3c89f8a..ff691df 100644 >>> --- a/target-s390x/cpu.c >>> +++ b/target-s390x/cpu.c >>> @@ -181,6 +181,9 @@ static void s390_cpu_initfn(Object *obj) >>> env->cpu_num = cpu_num++; >>> env->ext_index = -1; >>> >>> + env->facilities[0] = 0xc000000000000000ull; >>> + env->facilities[1] = 0; >> Could we add CPU definitions along the way here? I'm fine with making z9 the >> default CPU type, but we should make this explicit :). > Certainly that's what we should do. I just hadn't yet researched the > currently correct way to do that. I know there's some amount of out-of-date > examples in the current source base. I'll leave the answer to that to Andreas :). > > Pointers? > >>> static ExitStatus op_stfl(DisasContext *s, DisasOps *o) >>> { >>> - TCGv_i64 f, a; >>> - /* We really ought to have more complete indication of facilities >>> - that we implement. Address this when STFLE is implemented. */ >>> + TCGv_i64 f = tcg_temp_new_i64(); >>> + TCGv_i64 a = tcg_const_i64(200); >>> + >>> check_privileged(s); >>> - f = tcg_const_i64(0xc0000000); >>> - a = tcg_const_i64(200); >>> + tcg_gen_ld_i64(f, cpu_env, offsetof(CPUS390XState, facilities[0])); >>> + tcg_gen_shri_i64(f, f, 32); >> IMHO the facility list should be stored in DisasContext. That way we can check >> whether we're generating code against the correct target. > See patch 4. > > As for the code we generate here, does it really matter if we load the value > from env, or have it encoded as a constant? It still has to get stored to > memory, so it's not like the TCG optimizer is going to do anything with the > constant. No, it only seemed more straight forward to me from a "single source of information" point of view. But it really doesn't matter. Shifting in C seems to be easier to read :). Alex