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[174.21.81.121]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2076afe9c61sm5635915ad.231.2024.09.11.19.41.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 11 Sep 2024 19:41:34 -0700 (PDT) From: Richard Henderson To: qemu-devel@nongnu.org Cc: qemu-arm@nongnu.org, Peter Maydell Subject: [PATCH v3 21/29] target/arm: Split out subroutines of handle_shri_with_rndacc Date: Wed, 11 Sep 2024 19:41:06 -0700 Message-ID: <20240912024114.1097832-22-richard.henderson@linaro.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240912024114.1097832-1-richard.henderson@linaro.org> References: <20240912024114.1097832-1-richard.henderson@linaro.org> MIME-Version: 1.0 Received-SPF: pass client-ip=2607:f8b0:4864:20::62f; envelope-from=richard.henderson@linaro.org; helo=mail-pl1-x62f.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org There isn't a lot of commonality along the different paths of handle_shri_with_rndacc. Split them out to separate functions, which will be usable during the decodetree conversion. Simplify 64-bit rounding operations to not require double-word arithmetic. Reviewed-by: Peter Maydell Signed-off-by: Richard Henderson --- target/arm/tcg/translate-a64.c | 138 ++++++++++++++++++++------------- 1 file changed, 82 insertions(+), 56 deletions(-) diff --git a/target/arm/tcg/translate-a64.c b/target/arm/tcg/translate-a64.c index e59236330a..f4deacd554 100644 --- a/target/arm/tcg/translate-a64.c +++ b/target/arm/tcg/translate-a64.c @@ -7019,6 +7019,78 @@ static bool do_vec_shift_imm_wide(DisasContext *s, arg_qrri_e *a, bool is_u) TRANS(SSHLL_v, do_vec_shift_imm_wide, a, false) TRANS(USHLL_v, do_vec_shift_imm_wide, a, true) +static void gen_sshr_d(TCGv_i64 dst, TCGv_i64 src, int64_t shift) +{ + assert(shift >= 0 && shift <= 64); + tcg_gen_sari_i64(dst, src, MIN(shift, 63)); +} + +static void gen_ushr_d(TCGv_i64 dst, TCGv_i64 src, int64_t shift) +{ + assert(shift >= 0 && shift <= 64); + if (shift == 64) { + tcg_gen_movi_i64(dst, 0); + } else { + tcg_gen_shri_i64(dst, src, shift); + } +} + +static void gen_srshr_bhs(TCGv_i64 dst, TCGv_i64 src, int64_t shift) +{ + assert(shift >= 0 && shift <= 32); + if (shift) { + TCGv_i64 rnd = tcg_constant_i64(1ull << (shift - 1)); + tcg_gen_add_i64(dst, src, rnd); + tcg_gen_sari_i64(dst, dst, shift); + } else { + tcg_gen_mov_i64(dst, src); + } +} + +static void gen_urshr_bhs(TCGv_i64 dst, TCGv_i64 src, int64_t shift) +{ + assert(shift >= 0 && shift <= 32); + if (shift) { + TCGv_i64 rnd = tcg_constant_i64(1ull << (shift - 1)); + tcg_gen_add_i64(dst, src, rnd); + tcg_gen_shri_i64(dst, dst, shift); + } else { + tcg_gen_mov_i64(dst, src); + } +} + +static void gen_srshr_d(TCGv_i64 dst, TCGv_i64 src, int64_t shift) +{ + assert(shift >= 0 && shift <= 64); + if (shift == 0) { + tcg_gen_mov_i64(dst, src); + } else if (shift == 64) { + /* Extension of sign bit (0,-1) plus sign bit (0,1) is zero. */ + tcg_gen_movi_i64(dst, 0); + } else { + TCGv_i64 rnd = tcg_temp_new_i64(); + tcg_gen_extract_i64(rnd, src, shift - 1, 1); + tcg_gen_sari_i64(dst, src, shift); + tcg_gen_add_i64(dst, dst, rnd); + } +} + +static void gen_urshr_d(TCGv_i64 dst, TCGv_i64 src, int64_t shift) +{ + assert(shift >= 0 && shift <= 64); + if (shift == 0) { + tcg_gen_mov_i64(dst, src); + } else if (shift == 64) { + /* Rounding will propagate bit 63 into bit 64. */ + tcg_gen_shri_i64(dst, src, 63); + } else { + TCGv_i64 rnd = tcg_temp_new_i64(); + tcg_gen_extract_i64(rnd, src, shift - 1, 1); + tcg_gen_shri_i64(dst, src, shift); + tcg_gen_add_i64(dst, dst, rnd); + } +} + /* Shift a TCGv src by TCGv shift_amount, put result in dst. * Note that it is the caller's responsibility to ensure that the * shift amount is in range (ie 0..31 or 0..63) and provide the ARM @@ -9208,69 +9280,23 @@ static void handle_shri_with_rndacc(TCGv_i64 tcg_res, TCGv_i64 tcg_src, bool round, bool accumulate, bool is_u, int size, int shift) { - bool extended_result = false; - int ext_lshift = 0; - TCGv_i64 tcg_src_hi; - - if (round && size == 3) { - extended_result = true; - ext_lshift = 64 - shift; - tcg_src_hi = tcg_temp_new_i64(); - } else if (shift == 64) { - if (!accumulate && is_u) { - /* result is zero */ - tcg_gen_movi_i64(tcg_res, 0); - return; - } - } - - /* Deal with the rounding step */ - if (round) { - TCGv_i64 tcg_rnd = tcg_constant_i64(1ull << (shift - 1)); - if (extended_result) { - TCGv_i64 tcg_zero = tcg_constant_i64(0); - if (!is_u) { - /* take care of sign extending tcg_res */ - tcg_gen_sari_i64(tcg_src_hi, tcg_src, 63); - tcg_gen_add2_i64(tcg_src, tcg_src_hi, - tcg_src, tcg_src_hi, - tcg_rnd, tcg_zero); - } else { - tcg_gen_add2_i64(tcg_src, tcg_src_hi, - tcg_src, tcg_zero, - tcg_rnd, tcg_zero); - } + if (!round) { + if (is_u) { + gen_ushr_d(tcg_src, tcg_src, shift); } else { - tcg_gen_add_i64(tcg_src, tcg_src, tcg_rnd); + gen_sshr_d(tcg_src, tcg_src, shift); } - } - - /* Now do the shift right */ - if (round && extended_result) { - /* extended case, >64 bit precision required */ - if (ext_lshift == 0) { - /* special case, only high bits matter */ - tcg_gen_mov_i64(tcg_src, tcg_src_hi); + } else if (size == MO_64) { + if (is_u) { + gen_urshr_d(tcg_src, tcg_src, shift); } else { - tcg_gen_shri_i64(tcg_src, tcg_src, shift); - tcg_gen_shli_i64(tcg_src_hi, tcg_src_hi, ext_lshift); - tcg_gen_or_i64(tcg_src, tcg_src, tcg_src_hi); + gen_srshr_d(tcg_src, tcg_src, shift); } } else { if (is_u) { - if (shift == 64) { - /* essentially shifting in 64 zeros */ - tcg_gen_movi_i64(tcg_src, 0); - } else { - tcg_gen_shri_i64(tcg_src, tcg_src, shift); - } + gen_urshr_bhs(tcg_src, tcg_src, shift); } else { - if (shift == 64) { - /* effectively extending the sign-bit */ - tcg_gen_sari_i64(tcg_src, tcg_src, 63); - } else { - tcg_gen_sari_i64(tcg_src, tcg_src, shift); - } + gen_srshr_bhs(tcg_src, tcg_src, shift); } }