From: "Edgar E. Iglesias" <edgar.iglesias@gmail.com>
To: qemu-devel@nongnu.org
Subject: [Qemu-devel] [6198] CRIS: Slight performance improvement for flag evaluation.
Date: Wed, 07 Jan 2009 12:25:15 +0000 [thread overview]
Message-ID: <E1LKXTH-00051p-TS@cvs.savannah.gnu.org> (raw)
Revision: 6198
http://svn.sv.gnu.org/viewvc/?view=rev&root=qemu&revision=6198
Author: edgar_igl
Date: 2009-01-07 12:25:15 +0000 (Wed, 07 Jan 2009)
Log Message:
-----------
CRIS: Slight performance improvement for flag evaluation.
Translate sub and cmp ops separately when evaluating flags to avoid checking
for them at runtime.
Signed-off-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
Modified Paths:
--------------
trunk/target-cris/helper.h
trunk/target-cris/op_helper.c
trunk/target-cris/translate.c
Modified: trunk/target-cris/helper.h
===================================================================
--- trunk/target-cris/helper.h 2009-01-07 12:19:50 UTC (rev 6197)
+++ trunk/target-cris/helper.h 2009-01-07 12:25:15 UTC (rev 6198)
@@ -14,6 +14,7 @@
DEF_HELPER_0(evaluate_flags_mulu, void)
DEF_HELPER_0(evaluate_flags_mcp, void)
DEF_HELPER_0(evaluate_flags_alu_4, void)
+DEF_HELPER_0(evaluate_flags_sub_4, void)
DEF_HELPER_0(evaluate_flags_move_4, void)
DEF_HELPER_0(evaluate_flags_move_2, void)
DEF_HELPER_0(evaluate_flags, void)
Modified: trunk/target-cris/op_helper.c
===================================================================
--- trunk/target-cris/op_helper.c 2009-01-07 12:19:50 UTC (rev 6197)
+++ trunk/target-cris/op_helper.c 2009-01-07 12:25:15 UTC (rev 6198)
@@ -245,17 +245,19 @@
static void evaluate_flags_writeback(uint32_t flags)
{
- int x;
+ unsigned int x, z, mask;
/* Extended arithmetics, leave the z flag alone. */
x = env->cc_x;
- if ((x || env->cc_op == CC_OP_ADDC)
- && flags & Z_FLAG)
- env->cc_mask &= ~Z_FLAG;
+ mask = env->cc_mask | X_FLAG;
+ if (x) {
+ z = flags & Z_FLAG;
+ mask = mask & ~z;
+ }
+ flags &= mask;
/* all insn clear the x-flag except setf or clrf. */
- env->pregs[PR_CCS] &= ~(env->cc_mask | X_FLAG);
- flags &= env->cc_mask;
+ env->pregs[PR_CCS] &= ~mask;
env->pregs[PR_CCS] |= flags;
}
@@ -323,33 +325,25 @@
uint32_t res;
uint32_t flags = 0;
- src = env->cc_src;
- dst = env->cc_dest;
+ src = env->cc_src & 0x80000000;
+ dst = env->cc_dest & 0x80000000;
res = env->cc_result;
if ((res & 0x80000000L) != 0L)
{
flags |= N_FLAG;
- if (((src & 0x80000000L) == 0L)
- && ((dst & 0x80000000L) == 0L))
- {
+ if (!src && !dst)
flags |= V_FLAG;
- }
- else if (((src & 0x80000000L) != 0L) &&
- ((dst & 0x80000000L) != 0L))
- {
+ else if (src & dst)
flags |= R_FLAG;
- }
}
else
{
if (res == 0L)
flags |= Z_FLAG;
- if (((src & 0x80000000L) != 0L)
- && ((dst & 0x80000000L) != 0L))
+ if (src & dst)
flags |= V_FLAG;
- if ((dst & 0x80000000L) != 0L
- || (src & 0x80000000L) != 0L)
+ if (dst | src)
flags |= R_FLAG;
}
@@ -363,56 +357,61 @@
uint32_t res;
uint32_t flags = 0;
- src = env->cc_src;
- dst = env->cc_dest;
+ src = env->cc_src & 0x80000000;
+ dst = env->cc_dest & 0x80000000;
+ res = env->cc_result;
- /* Reconstruct the result. */
- switch (env->cc_op)
+ if ((res & 0x80000000L) != 0L)
{
- case CC_OP_SUB:
- res = dst - src;
- break;
- case CC_OP_ADD:
- res = dst + src;
- break;
- default:
- res = env->cc_result;
- break;
+ flags |= N_FLAG;
+ if (!src && !dst)
+ flags |= V_FLAG;
+ else if (src & dst)
+ flags |= C_FLAG;
}
+ else
+ {
+ if (res == 0L)
+ flags |= Z_FLAG;
+ if (src & dst)
+ flags |= V_FLAG;
+ if (dst | src)
+ flags |= C_FLAG;
+ }
- if (env->cc_op == CC_OP_SUB || env->cc_op == CC_OP_CMP)
- src = ~src;
+ evaluate_flags_writeback(flags);
+}
+void helper_evaluate_flags_sub_4(void)
+{
+ uint32_t src;
+ uint32_t dst;
+ uint32_t res;
+ uint32_t flags = 0;
+
+ src = (~env->cc_src) & 0x80000000;
+ dst = env->cc_dest & 0x80000000;
+ res = env->cc_result;
+
if ((res & 0x80000000L) != 0L)
{
flags |= N_FLAG;
- if (((src & 0x80000000L) == 0L)
- && ((dst & 0x80000000L) == 0L))
- {
+ if (!src && !dst)
flags |= V_FLAG;
- }
- else if (((src & 0x80000000L) != 0L) &&
- ((dst & 0x80000000L) != 0L))
- {
+ else if (src & dst)
flags |= C_FLAG;
- }
}
else
{
if (res == 0L)
flags |= Z_FLAG;
- if (((src & 0x80000000L) != 0L)
- && ((dst & 0x80000000L) != 0L))
+ if (src & dst)
flags |= V_FLAG;
- if ((dst & 0x80000000L) != 0L
- || (src & 0x80000000L) != 0L)
+ if (dst | src)
flags |= C_FLAG;
}
- if (env->cc_op == CC_OP_SUB
- || env->cc_op == CC_OP_CMP) {
- flags ^= C_FLAG;
- }
+ flags ^= C_FLAG;
evaluate_flags_writeback(flags);
}
@@ -607,6 +606,13 @@
case CC_OP_FLAGS:
/* live. */
break;
+ case CC_OP_SUB:
+ case CC_OP_CMP:
+ if (env->cc_size == 4)
+ helper_evaluate_flags_sub_4();
+ else
+ helper_evaluate_flags();
+ break;
default:
{
switch (env->cc_size)
Modified: trunk/target-cris/translate.c
===================================================================
--- trunk/target-cris/translate.c 2009-01-07 12:19:50 UTC (rev 6197)
+++ trunk/target-cris/translate.c 2009-01-07 12:25:15 UTC (rev 6198)
@@ -728,8 +728,15 @@
case CC_OP_FLAGS:
/* live. */
break;
+ case CC_OP_SUB:
+ case CC_OP_CMP:
+ if (dc->cc_size == 4)
+ gen_helper_evaluate_flags_sub_4();
+ else
+ gen_helper_evaluate_flags();
+
+ break;
default:
- {
switch (dc->cc_size)
{
case 4:
@@ -739,7 +746,6 @@
gen_helper_evaluate_flags();
break;
}
- }
break;
}
if (dc->flagx_known) {
@@ -821,13 +827,8 @@
/* Update cc after executing ALU op. needs the result. */
static inline void cris_update_result(DisasContext *dc, TCGv res)
{
- if (dc->update_cc) {
- if (dc->cc_size == 4 &&
- (dc->cc_op == CC_OP_SUB
- || dc->cc_op == CC_OP_ADD))
- return;
+ if (dc->update_cc)
tcg_gen_mov_tl(cc_result, res);
- }
}
/* Returns one if the write back stage should execute. */
@@ -1890,6 +1891,10 @@
DIS(fprintf (logfile, "addc $r%u, $r%u\n",
dc->op1, dc->op2));
cris_evaluate_flags(dc);
+ /* Set for this insn. */
+ dc->flagx_known = 1;
+ dc->flags_x = X_FLAG;
+
cris_cc_mask(dc, CC_MASK_NZVC);
cris_alu(dc, CC_OP_ADDC,
cpu_R[dc->op2], cpu_R[dc->op2], cpu_R[dc->op1], 4);
@@ -2615,6 +2620,11 @@
dc->op2));
cris_evaluate_flags(dc);
+
+ /* Set for this insn. */
+ dc->flagx_known = 1;
+ dc->flags_x = X_FLAG;
+
cris_alu_m_alloc_temps(t);
insn_len = dec_prep_alu_m(dc, 0, 4, t[0], t[1]);
cris_cc_mask(dc, CC_MASK_NZVC);
reply other threads:[~2009-01-07 12:25 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=E1LKXTH-00051p-TS@cvs.savannah.gnu.org \
--to=edgar.iglesias@gmail.com \
--cc=qemu-devel@nongnu.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).