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>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6198 c046a42c-6fe2-441c-8c8c-71466251a162
diff --git a/target-cris/op_helper.c b/target-cris/op_helper.c
index 5db4575..51323a2 100644
--- a/target-cris/op_helper.c
+++ b/target-cris/op_helper.c
@@ -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;
-
- /* Reconstruct the result. */
- switch (env->cc_op)
- {
- case CC_OP_SUB:
- res = dst - src;
- break;
- case CC_OP_ADD:
- res = dst + src;
- break;
- default:
- res = env->cc_result;
- break;
- }
-
- if (env->cc_op == CC_OP_SUB || env->cc_op == CC_OP_CMP)
- src = ~src;
+ 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;
+ 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 && !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;
+ }
+
+ 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)
