From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:45400) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1c75qX-00047b-9n for qemu-devel@nongnu.org; Wed, 16 Nov 2016 14:26:14 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1c75qW-0005vI-3Q for qemu-devel@nongnu.org; Wed, 16 Nov 2016 14:26:13 -0500 Received: from mail-wm0-x241.google.com ([2a00:1450:400c:c09::241]:36630) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1c75qV-0005v0-T7 for qemu-devel@nongnu.org; Wed, 16 Nov 2016 14:26:12 -0500 Received: by mail-wm0-x241.google.com with SMTP id m203so14288566wma.3 for ; Wed, 16 Nov 2016 11:26:11 -0800 (PST) Sender: Richard Henderson From: Richard Henderson Date: Wed, 16 Nov 2016 20:25:24 +0100 Message-Id: <1479324335-2074-15-git-send-email-rth@twiddle.net> In-Reply-To: <1479324335-2074-1-git-send-email-rth@twiddle.net> References: <1479324335-2074-1-git-send-email-rth@twiddle.net> Subject: [Qemu-devel] [PATCH 14/25] target-i386: Use clz and ctz opcodes List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Eduardo Habkost Cc: Eduardo Habkost Signed-off-by: Richard Henderson --- target-i386/helper.h | 2 -- target-i386/int_helper.c | 11 ----------- target-i386/translate.c | 31 ++++++++++++++----------------- 3 files changed, 14 insertions(+), 30 deletions(-) diff --git a/target-i386/helper.h b/target-i386/helper.h index 4e859eb..1e76b09 100644 --- a/target-i386/helper.h +++ b/target-i386/helper.h @@ -201,8 +201,6 @@ DEF_HELPER_FLAGS_3(xsetbv, TCG_CALL_NO_WG, void, env, i32, i64) DEF_HELPER_FLAGS_2(rdpkru, TCG_CALL_NO_WG, i64, env, i32) DEF_HELPER_FLAGS_3(wrpkru, TCG_CALL_NO_WG, void, env, i32, i64) -DEF_HELPER_FLAGS_1(clz, TCG_CALL_NO_RWG_SE, tl, tl) -DEF_HELPER_FLAGS_1(ctz, TCG_CALL_NO_RWG_SE, tl, tl) DEF_HELPER_FLAGS_2(pdep, TCG_CALL_NO_RWG_SE, tl, tl, tl) DEF_HELPER_FLAGS_2(pext, TCG_CALL_NO_RWG_SE, tl, tl, tl) diff --git a/target-i386/int_helper.c b/target-i386/int_helper.c index 9e873ac..4dc5c65 100644 --- a/target-i386/int_helper.c +++ b/target-i386/int_helper.c @@ -417,17 +417,6 @@ void helper_idivq_EAX(CPUX86State *env, target_ulong t0) # define clztl clz64 #endif -/* bit operations */ -target_ulong helper_ctz(target_ulong t0) -{ - return ctztl(t0); -} - -target_ulong helper_clz(target_ulong t0) -{ - return clztl(t0); -} - target_ulong helper_pdep(target_ulong src, target_ulong mask) { target_ulong dest = 0; diff --git a/target-i386/translate.c b/target-i386/translate.c index 4d6d36f..0eac334 100644 --- a/target-i386/translate.c +++ b/target-i386/translate.c @@ -6792,21 +6792,18 @@ static target_ulong disas_insn(CPUX86State *env, DisasContext *s, ? s->cpuid_ext3_features & CPUID_EXT3_ABM : s->cpuid_7_0_ebx_features & CPUID_7_0_EBX_BMI1)) { int size = 8 << ot; + /* For lzcnt/tzcnt, C bit is defined related to the input. */ tcg_gen_mov_tl(cpu_cc_src, cpu_T0); if (b & 1) { /* For lzcnt, reduce the target_ulong result by the number of zeros that we expect to find at the top. */ - gen_helper_clz(cpu_T0, cpu_T0); + tcg_gen_clzi_tl(cpu_T0, cpu_T0, TARGET_LONG_BITS); tcg_gen_subi_tl(cpu_T0, cpu_T0, TARGET_LONG_BITS - size); } else { - /* For tzcnt, a zero input must return the operand size: - force all bits outside the operand size to 1. */ - target_ulong mask = (target_ulong)-2 << (size - 1); - tcg_gen_ori_tl(cpu_T0, cpu_T0, mask); - gen_helper_ctz(cpu_T0, cpu_T0); - } - /* For lzcnt/tzcnt, C and Z bits are defined and are - related to the result. */ + /* For tzcnt, a zero input must return the operand size. */ + tcg_gen_ctzi_tl(cpu_T0, cpu_T0, size); + } + /* For lzcnt/tzcnt, Z bit is defined related to the result. */ gen_op_update1_cc(); set_cc_op(s, CC_OP_BMILGB + ot); } else { @@ -6814,20 +6811,20 @@ static target_ulong disas_insn(CPUX86State *env, DisasContext *s, to the input and not the result. */ tcg_gen_mov_tl(cpu_cc_dst, cpu_T0); set_cc_op(s, CC_OP_LOGICB + ot); + + /* ??? The manual says that the output is undefined when the + input is zero, but real hardware leaves it unchanged, and + real programs appear to depend on that. Accomplish this + by passing the output as the value to return upon zero. */ if (b & 1) { /* For bsr, return the bit index of the first 1 bit, not the count of leading zeros. */ - gen_helper_clz(cpu_T0, cpu_T0); + tcg_gen_xori_tl(cpu_T1, cpu_regs[reg], TARGET_LONG_BITS - 1); + tcg_gen_clz_tl(cpu_T0, cpu_T0, cpu_T1); tcg_gen_xori_tl(cpu_T0, cpu_T0, TARGET_LONG_BITS - 1); } else { - gen_helper_ctz(cpu_T0, cpu_T0); + tcg_gen_ctz_tl(cpu_T0, cpu_T0, cpu_regs[reg]); } - /* ??? The manual says that the output is undefined when the - input is zero, but real hardware leaves it unchanged, and - real programs appear to depend on that. */ - tcg_gen_movi_tl(cpu_tmp0, 0); - tcg_gen_movcond_tl(TCG_COND_EQ, cpu_T0, cpu_cc_dst, cpu_tmp0, - cpu_regs[reg], cpu_T0); } gen_op_mov_reg_v(ot, reg, cpu_T0); break; -- 2.7.4