diff options
author | edgar_igl <edgar_igl@c046a42c-6fe2-441c-8c8c-71466251a162> | 2009-01-07 12:25:15 +0000 |
---|---|---|
committer | edgar_igl <edgar_igl@c046a42c-6fe2-441c-8c8c-71466251a162> | 2009-01-07 12:25:15 +0000 |
commit | a8cf66bb393ff420d40ae172a4c817bf2752918a (patch) | |
tree | 69a348d323293461b93e1e6ba46e76beeefa8841 /target-cris/op_helper.c | |
parent | 10c144e2fbc985d85e4ce5370dc2e97afe47403f (diff) | |
download | qemu-a8cf66bb393ff420d40ae172a4c817bf2752918a.zip qemu-a8cf66bb393ff420d40ae172a4c817bf2752918a.tar.gz qemu-a8cf66bb393ff420d40ae172a4c817bf2752918a.tar.bz2 |
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
Diffstat (limited to 'target-cris/op_helper.c')
-rw-r--r-- | target-cris/op_helper.c | 108 |
1 files changed, 57 insertions, 51 deletions
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 @@ void helper_rfn(void) 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 @@ void helper_evaluate_flags_mcp(void) 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 @@ void helper_evaluate_flags_alu_4(void) 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 @@ void helper_top_evaluate_flags(void) 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) |