From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:52646) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZQGSs-0007ns-1t for qemu-devel@nongnu.org; Fri, 14 Aug 2015 11:00:15 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZQGSr-0006dX-0A for qemu-devel@nongnu.org; Fri, 14 Aug 2015 11:00:13 -0400 Received: from mail-qg0-x22f.google.com ([2607:f8b0:400d:c04::22f]:34660) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZQGSq-0006dK-S6 for qemu-devel@nongnu.org; Fri, 14 Aug 2015 11:00:12 -0400 Received: by qgeg42 with SMTP id g42so53467815qge.1 for ; Fri, 14 Aug 2015 08:00:12 -0700 (PDT) Sender: Richard Henderson From: Richard Henderson Date: Fri, 14 Aug 2015 07:59:23 -0700 Message-Id: <1439564366-11633-9-git-send-email-rth@twiddle.net> In-Reply-To: <1439564366-11633-1-git-send-email-rth@twiddle.net> References: <1439564366-11633-1-git-send-email-rth@twiddle.net> Subject: [Qemu-devel] [PATCH 08/11] target-m68k: Optimize some comparisons List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: peter.maydell@linaro.org, schwab@linux-m68k.org, laurent@vivier.eu, gerg@uclinux.org Signed-off-by: Richard Henderson --- target-m68k/translate.c | 108 +++++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 102 insertions(+), 6 deletions(-) diff --git a/target-m68k/translate.c b/target-m68k/translate.c index 28c3e1e..6f60c6f 100644 --- a/target-m68k/translate.c +++ b/target-m68k/translate.c @@ -793,10 +793,43 @@ static void gen_cc_cond(DisasCompare *c, DisasContext *s, int cond) { TCGv tmp, tmp2; TCGCond tcond; + CCOp op = s->cc_op; - /* TODO: Optimize compare/branch pairs rather than always flushing - flag state to CC_OP_FLAGS. */ - gen_flush_flags(s); + /* The CC_OP_CMP form can handle most normal comparisons directly. */ + if (op == CC_OP_CMP) { + c->g1 = c->g2 = 1; + c->v1 = QREG_CC_N; + c->v2 = QREG_CC_V; + switch (cond) { + case 2: /* HI */ + case 3: /* LS */ + tcond = TCG_COND_LEU; + goto done; + case 4: /* CC */ + case 5: /* CS */ + tcond = TCG_COND_LTU; + goto done; + case 6: /* NE */ + case 7: /* EQ */ + tcond = TCG_COND_EQ; + goto done; + case 10: /* PL */ + case 11: /* MI */ + c->g1 = c->g2 = 0; + c->v2 = tcg_const_i32(0); + c->v1 = tmp = tcg_temp_new(); + tcg_gen_sub_i32(tmp, QREG_CC_N, QREG_CC_V); + /* fallthru */ + case 12: /* GE */ + case 13: /* LT */ + tcond = TCG_COND_LT; + goto done; + case 14: /* GT */ + case 15: /* LE */ + tcond = TCG_COND_LE; + goto done; + } + } c->g1 = 1; c->g2 = 0; @@ -807,7 +840,71 @@ static void gen_cc_cond(DisasCompare *c, DisasContext *s, int cond) case 1: /* F */ c->v1 = c->v2; tcond = TCG_COND_NEVER; + goto done; + case 14: /* GT (!(Z || (N ^ V))) */ + case 15: /* LE (Z || (N ^ V)) */ + /* Logic operations clear V, which simplifies LE to (Z || N), + and since Z and N are co-located, this becomes a normal + comparison vs N. */ + if (op == CC_OP_LOGIC) { + c->v1 = QREG_CC_N; + tcond = TCG_COND_LE; + goto done; + } + break; + case 12: /* GE (!(N ^ V)) */ + case 13: /* LT (N ^ V) */ + /* Logic operations clear V, which simplifies this to N. */ + if (op != CC_OP_LOGIC) { + break; + } + /* fallthru */ + case 10: /* PL (!N) */ + case 11: /* MI (N) */ + /* Several cases represent N normally. */ + if (op == CC_OP_ADD || op == CC_OP_SUB || op == CC_OP_LOGIC) { + c->v1 = QREG_CC_N; + tcond = TCG_COND_LT; + goto done; + } + break; + case 6: /* NE (!Z) */ + case 7: /* EQ (Z) */ + /* Some cases fold Z into N. */ + if (op == CC_OP_ADD || op == CC_OP_SUB || op == CC_OP_LOGIC) { + tcond = TCG_COND_EQ; + c->v1 = QREG_CC_N; + goto done; + } break; + case 4: /* CC (!C) */ + case 5: /* CS (C) */ + /* Some cases fold C into X. */ + if (op == CC_OP_ADD || op == CC_OP_SUB) { + tcond = TCG_COND_NE; + c->v1 = QREG_CC_X; + goto done; + } + /* fallthru */ + case 8: /* VC (!V) */ + case 9: /* VS (V) */ + /* Logic operations clear V and C. */ + if (op == CC_OP_LOGIC) { + tcond = TCG_COND_NEVER; + c->v2 = c->v1; + } + break; + } + + /* Otherwise, flush flag state to CC_OP_FLAGS. */ + gen_flush_flags(s); + + switch (cond) { + case 0: /* T */ + case 1: /* F */ + default: + /* Invalid, or handled above. */ + abort(); case 2: /* HI (!C && !Z) -> !(C || Z)*/ case 3: /* LS (C || Z) */ c->v1 = tmp = tcg_temp_new(); @@ -855,10 +952,9 @@ static void gen_cc_cond(DisasCompare *c, DisasContext *s, int cond) tcg_temp_free(tmp2); tcond = TCG_COND_LT; break; - default: - /* Should ever happen. */ - abort(); } + + done: if ((cond & 1) == 0) { tcond = tcg_invert_cond(tcond); } -- 2.4.3