From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:33781) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WKsm8-0002B0-GT for qemu-devel@nongnu.org; Tue, 04 Mar 2014 12:05:10 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WKsm2-0001oY-NV for qemu-devel@nongnu.org; Tue, 04 Mar 2014 12:05:04 -0500 Received: from mail-qg0-x22a.google.com ([2607:f8b0:400d:c04::22a]:44445) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WKsm2-0001oO-J2 for qemu-devel@nongnu.org; Tue, 04 Mar 2014 12:04:58 -0500 Received: by mail-qg0-f42.google.com with SMTP id q107so16118485qgd.1 for ; Tue, 04 Mar 2014 09:04:58 -0800 (PST) Sender: Richard Henderson From: Richard Henderson Date: Tue, 4 Mar 2014 09:04:09 -0800 Message-Id: <1393952650-16802-10-git-send-email-rth@twiddle.net> In-Reply-To: <1393952650-16802-1-git-send-email-rth@twiddle.net> References: <1393952650-16802-1-git-send-email-rth@twiddle.net> Subject: [Qemu-devel] [PATCH 09/10] tcg-aarch64: Simplify tcg_out_ldst_9 encoding List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Peter Maydell , Claudio Fontana At first glance the code appears to be using 1's compliment encoding, a-la AArch32. Except that the constant is "off", creating a complicated split field 2's compliment encoding. Much clearer to just use a normal mask and shift. Signed-off-by: Richard Henderson --- tcg/aarch64/tcg-target.c | 14 ++------------ 1 file changed, 2 insertions(+), 12 deletions(-) diff --git a/tcg/aarch64/tcg-target.c b/tcg/aarch64/tcg-target.c index 58a5ff3..d75d685 100644 --- a/tcg/aarch64/tcg-target.c +++ b/tcg/aarch64/tcg-target.c @@ -305,18 +305,8 @@ static inline void tcg_out_ldst_9(TCGContext *s, TCGReg rd, TCGReg rn, tcg_target_long offset) { /* use LDUR with BASE register with 9bit signed unscaled offset */ - unsigned int mod, off; - - if (offset < 0) { - off = (256 + offset); - mod = 0x1; - } else { - off = offset; - mod = 0x0; - } - - mod |= op_type; - tcg_out32(s, op_data << 24 | mod << 20 | off << 12 | rn << 5 | rd); + tcg_out32(s, op_data << 24 | op_type << 20 + | (offset & 0x1ff) << 12 | rn << 5 | rd); } /* tcg_out_ldst_12 expects a scaled unsigned immediate offset */ -- 1.8.5.3