Always perform a sign-extending load. In the extremely unlikely
case that we've used an 0x66 prefix, the extension to 64-bits is
unnecessary but not wrong; the store will still examine only 16 bits.
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>
We can use the MO_SIGN bit to tidy the reg-reg switch statement
as well as pass it on to gen_op_ld_v, eliminating one call.
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>
By inspection, obviously we should be storing T[1] not T[0].
This could only happen for x86_64 in 64-bit mode with 0x66
prefix to call insn -- i.e. never.
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>
Too many places have the same test vs OR_TMP0 to indicate
a write back to memory. Hoist that to a subroutine.
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>
Replace its users by gen_op_ld_v with the MO_SIGN bit set.
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>
The MO_8/16/32/64 constants have the same encoding and meaning
as the OT_BYTE/WORD/LONG/QUAD. Since we rely on them being the
same, for the qemu_ld/st helpers, standardize on the common names.
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>
In preference to the older helpers. Stores only in this patch.
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>
In preference to the older helpers. Loads only in this patch.
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>
Now that we don't combine mem_index with operand size info,
we don't need to encode it. Which tidies many places that
access it.
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>
Rather than add s->mem_index into a combined size+mem_index
argument, pass the context down. This will allow cleaning
up s->mem_index later.
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>
After commit b1bbfe7 (aio / timers: On timer modification, qemu_notify
or aio_notify, 2013-08-21) FreeBSD guests report a huge slowdown.
The problem shows up as soon as FreeBSD turns out its periodic (~1 ms)
tick, but the timers are only the trigger for a pre-existing problem.
Before the offending patch, setting a timer did a timer_settime system call.
After, setting the timer exits the event loop (which uses poll) and
reenters it with a new deadline. This does not cause any slowdown; the
difference is between one system call (timer_settime and a signal
delivery (SIGALRM) before the patch, and two system calls afterwards
(write to a pipe or eventfd + calling poll again when re-entering the
event loop).
Unfortunately, the exit/enter causes the main loop to grab the iothread
lock, which in turns kicks the VCPU thread out of execution. This
causes TCG to execute the next VCPU in its round-robin scheduling of
VCPUS. When the second VCPU is mostly unused, FreeBSD runs a "pause"
instruction in its idle loop which only burns cycles without any
progress. As soon as the timer tick expires, the first VCPU runs
the interrupt handler but very soon it sets it again---and QEMU
then goes back doing nothing in the second VCPU.
The fix is to make the pause instruction do "cpu_loop_exit".
Cc: Richard Henderson <rth@twiddle.net>
Reported-by: Luigi Rizzo <rizzo@iet.unipi.it>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Message-id: 1384948442-24217-1-git-send-email-pbonzini@redhat.com
Signed-off-by: Anthony Liguori <aliguori@amazon.com>
The instructions CMOVcc, FCMOVcc and F[U]COMI[P] should only be
present if the CMOV feature bit is set. Add missing feature bit
checks so we correctly fault if emulating a 486 or 586.
This fixes bug LP:1201446.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>
Prepares for changing cpu_single_step() argument to CPUState.
Acked-by: Michael Walle <michael@walle.cc> (for lm32)
Signed-off-by: Andreas Färber <afaerber@suse.de>
Also use bool type while at it.
Prepares for moving singlestep_enabled field to CPUState.
Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Andreas Färber <afaerber@suse.de>
The code reorganization in commit 4a6fd938 broke handling of PREFIX_ADR.
While fixing this, tidy and comment the code so that it's more obvious
what's going on in setting both aflag and dflag.
The TARGET_X86_64 ifdef can be eliminated because CODE64 expands to the
constant zero when TARGET_X86_64 is undefined.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Reported-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Richard Henderson <rth@twiddle.net>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 1369855851-21400-1-git-send-email-rth@twiddle.net
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Fix EFLAGS corruption by ROR r8/r16 imm instruction located at the end
of the TB, similarly to commit 089305ac for the non-immediate case.
Reported-by: Hervé Poussineau <hpoussin@reactos.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
This replaces the feature-bit fields on both X86CPU and x86_def_t
structs with an array.
With this, we will be able to simplify code that simply does the same
operation on all feature words (e.g. kvm_check_features_against_host(),
filter_features_for_kvm(), add_flagname_to_bitmaps(), CPU feature-bit
property lookup/registration, and the proposed "feature-words" property)
The following field replacements were made on X86CPU and x86_def_t:
(cpuid_)features -> features[FEAT_1_EDX]
(cpuid_)ext_features -> features[FEAT_1_ECX]
(cpuid_)ext2_features -> features[FEAT_8000_0001_EDX]
(cpuid_)ext3_features -> features[FEAT_8000_0001_ECX]
(cpuid_)ext4_features -> features[FEAT_C000_0001_EDX]
(cpuid_)kvm_features -> features[FEAT_KVM]
(cpuid_)svm_features -> features[FEAT_SVM]
(cpuid_)7_0_ebx_features -> features[FEAT_7_0_EBX]
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
Fixed EFLAGS corruption by ROR r8/r16 instruction located at the end of the TB.
Signed-off-by: Pavel Dovgalyuk <pavel.dovgaluk@gmail.com>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
gen_op_mov_TN_reg() loads the value in cpu_T[0], so this temporary should
be used instead of cpu_tmp0.
Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
When starting from CC_OP_DYNAMIC, and issuing adox before adcx,
a typo used the wrong value for the resulting CC_OP.
Cc: Blue Swirl <blauwirbel@gmail.com>
Reported-by: Torbjorn Granlund <tg@gmplib.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
Fix various typos and misspellings. The bulk of these were found with
codespell.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Stefan Weil <sw@weilnetz.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
The gen_icount_start/end functions are now somewhat misnamed since they
are useful for generic "start/end of TB" code, used for more than just
icount. Rename them to gen_tb_start/end.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
These correspond very closely to the insns that we're emulating.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
The shift and rotate insns use movcond to set CC_OP, and thus
achieve a conditional EFLAGS setting. By discarding CC_OP in
a later flags setting insn, we can discard that movcond.
Signed-off-by: Richard Henderson <rth@twiddle.net>
We weren't computing flags for lzcnt at all. At the same time,
adjust the implementation of bsf/bsr to avoid the local branch,
using movcond instead.
Signed-off-by: Richard Henderson <rth@twiddle.net>
As this is the first of the BMI insns to be implemented,
this carries quite a bit more baggage than normal.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Add another slot in ENV and store two of the three inputs. This lets us
do less work when carry-out is not needed, and avoids the unpredictable
CC_OP after translating these insns.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Pass the data in explicitly, rather than indirectly via env.
This avoids all sorts of unnecessary register spillage.
Signed-off-by: Richard Henderson <rth@twiddle.net>
After a comparison or subtraction, the original value of the LHS will
currently be reconstructed using an addition. However, in most cases
it is already available: store it in a temp-local variable and save 1
or 2 TCG ops (2 if the result of the addition needs to be extended).
The temp-local can be declared dead as soon as the cc_op changes again,
or also before the translation block ends because gen_prepare_cc will
always make a copy before returning it. All this magic, plus copy
propagation and dead-code elimination, ensures that the temp local will
(almost) never be spilled.
Example (cmp $0x21,%rax + jbe):
Before After
----------------------------------------------------------------------------
movi_i64 tmp1,$0x21 movi_i64 tmp1,$0x21
movi_i64 cc_src,$0x21 movi_i64 cc_src,$0x21
sub_i64 cc_dst,rax,tmp1 sub_i64 cc_dst,rax,tmp1
add_i64 tmp7,cc_dst,cc_src
movi_i32 cc_op,$0x11 movi_i32 cc_op,$0x11
brcond_i64 tmp7,cc_src,leu,$0x0 discard loc11
brcond_i64 rax,cc_src,leu,$0x0
Before After
----------------------------------------------------------------------------
mov (%r14),%rbp mov (%r14),%rbp
mov %rbp,%rbx mov %rbp,%rbx
sub $0x21,%rbx sub $0x21,%rbx
lea 0x21(%rbx),%r12
movl $0x11,0xa0(%r14) movl $0x11,0xa0(%r14)
movq $0x21,0x90(%r14) movq $0x21,0x90(%r14)
mov %rbx,0x98(%r14) mov %rbx,0x98(%r14)
cmp $0x21,%r12 | cmp $0x21,%rbp
jbe ... jbe ...
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Richard Henderson <rth@twiddle.net>
Placing the CC_OP_DYNAMIC at the join is less effective than
before the branch, as the branch will have forced global registers
to their home locations. This way we have a chance to discard
CC_SRC2 before it gets stored.
Signed-off-by: Richard Henderson <rth@twiddle.net>
A jump that ends a basic block or otherwise falls back to CC_OP_DYNAMIC
will always have to call gen_op_set_cc_op. However, not all jumps end
a basic block, so introduce a variant that does not do this.
This was partially undone earlier (i386: drop cc_op argument of gen_jcc1),
redo it now also to prepare for the introduction of src2.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Richard Henderson <rth@twiddle.net>
Replace low-level ops with a higher-level "cmp %al, (A0)" in the case
of scas, and "cmp T0, (A0)" in the case of cmps.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Richard Henderson <rth@twiddle.net>
It is almost unused, and it is simpler to pass a TCG value directly
to gen_shiftd_rm_T1_T3. This value is then written to t2 without
going through a temporary register.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Richard Henderson <rth@twiddle.net>
This simplifies all the jump generation code. CCPrepare allows the
code to create an efficient brcond always, so there is no need to
duplicate the setcc and jcc code.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Richard Henderson <rth@twiddle.net>
This makes the i386 front-end able to create CCPrepare structs for all
condition, not just those that come from a single flag. In particular,
JCC_L and JCC_LE can be optimized because gen_prepare_cc is not forced
to return a result in bit 0 (unlike gen_setcc_slow).
However, for now the slow jcc operations will still go through CC
computation in a single-bit temporary, followed by a brcond if the
temporary is nonzero.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Richard Henderson <rth@twiddle.net>
Introduce a struct that describes how to build a *cond operation
that checks for a given x86 condition code. For now, just change
gen_compute_eflags_* to return the new struct, generate code for
the CCPrepare struct, and go on as before.
[rth: Use ctz with the proper width rather than ffs.]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Richard Henderson <rth@twiddle.net>
Reconstruct the arguments for complex conditions involving CC_OP_SUBx (BE,
L, LE). In the others do it via setcond and gen_setcc_slow (which is
not that slow in many cases).
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Richard Henderson <rth@twiddle.net>
And allow gen_setcc_slow to operate on cpu_cc_src.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Richard Henderson <rth@twiddle.net>
This is looking at EFLAGS, but it can do so more efficiently with
setcond.
Reviewed-by: Blue Swirl <blauwirbel@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Richard Henderson <rth@twiddle.net>
Do not hard code the destination register.
Reviewed-by: Blue Swirl <blauwirbel@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Richard Henderson <rth@twiddle.net>
Do the switch at translation time, converting the helper templates to
TCG opcodes. In some cases CF can be computed with a single setcond,
though others it may require a little more work.
In the CC_OP_DYNAMIC case, compute the whole EFLAGS, same as for ZF/SF/PF.
Reviewed-by: Blue Swirl <blauwirbel@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Richard Henderson <rth@twiddle.net>
Make gen_compute_eflags_z and gen_compute_eflags_s able to compute the
inverted condition, and use this in gen_setcc_slow_T0. We cannot do it
yet in gen_compute_eflags_c, but prepare the code for it anyway. It is
not worthwhile for PF, as usual.
shr+and+xor could be replaced by and+setcond. I'm not doing it yet.
Reviewed-by: Blue Swirl <blauwirbel@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Richard Henderson <rth@twiddle.net>
ZF, SF and PF can always be computed from CC_DST except in the
CC_OP_EFLAGS case (and CC_OP_DYNAMIC, which just resolves to CC_OP_EFLAGS
in gen_compute_eflags). Use setcond to compute ZF and SF.
We could also use a table lookup to compute PF.
Reviewed-by: Blue Swirl <blauwirbel@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Richard Henderson <rth@twiddle.net>
This gets us universal coverage, rather than scattering discards
around at various places. As a bonus, we do not emit redundant
discards e.g. between sequential logic insns.
Signed-off-by: Richard Henderson <rth@twiddle.net>
This makes code more similar to the other callers of gen_eob, especially
loopz/loopnz/jcxz.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Richard Henderson <rth@twiddle.net>
After calling gen_compute_eflags, leave the computed value in cc_reg_src
and set cc_op to CC_OP_EFLAGS. The next few patches will remove anyway
most calls to gen_compute_eflags.
As a result of this change it is more natural to remove the register
argument from gen_compute_eflags and change all the callers.
Reviewed-by: Blue Swirl <blauwirbel@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Richard Henderson <rth@twiddle.net>
Introduce new functions to extract PF, SF, OF, ZF in addition to CF.
These provide single entry points for optimizing accesses to a single
flag.
Reviewed-by: Blue Swirl <blauwirbel@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Richard Henderson <rth@twiddle.net>
All of the conditional calls to gen_op_set_cc_op go away, and
gen_op_set_cc_op itself gets inlined into its only remaining caller.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Use a dirty flag to know whether env->cc_op is up to date,
rather than forcing s->cc_op to DYNAMIC and losing info.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Before computing flags we need to store the cc_op to memory. Move this
to gen_compute_eflags_c and gen_compute_eflags rather than doing it all
over the place.
Alo, after computing the flags in cpu_cc_src we are in EFLAGS mode.
Set s->cc_op and discard cpu_cc_dst in gen_compute_eflags, rather than
doing it all over the place.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Richard Henderson <rth@twiddle.net>
Discard CC_DST and set s->cc_op immediately after computing EFLAGS.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Richard Henderson <rth@twiddle.net>
Always compute EFLAGS first since it is needed whenever
the shift is non-zero, i.e. most of the time. This makes it possible
to remove some writes of CC_OP_EFLAGS to cpu_cc_op and more importantly
removes cases where s->cc_op becomes CC_OP_DYNAMIC. Also, we can
remove cc_tmp and just modify cc_src from within the helper.
Finally, always follow gen_compute_eflags(cpu_cc_src) by setting s->cc_op
and discarding cpu_cc_dst.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Richard Henderson <rth@twiddle.net>
This ensures the invariant that cpu_cc_op matches s->cc_op when calling
the helpers. The next patches need this because gen_compute_eflags and
gen_compute_eflags_c will take care of setting cpu_cc_op.
Always compute EFLAGS first since it is needed whenever the shift is
non-zero, i.e. most of the time. This makes it possible to remove some
writes of CC_OP_EFLAGS to cpu_cc_op and more importantly removes cases
where s->cc_op becomes CC_OP_DYNAMIC. These are slow and we want to
avoid them: CC_OP_EFLAGS is quite efficient once we paid the initial
cost of computing the flags.
Finally, always follow gen_compute_eflags(cpu_cc_src) by setting s->cc_op
and discarding cpu_cc_dst.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Richard Henderson <rth@twiddle.net>
This ensures the invariant that cpu_cc_op matches s->cc_op when calling
the helpers. The next patches need this because gen_compute_eflags and
gen_compute_eflags_c will take care of setting cpu_cc_op.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Richard Henderson <rth@twiddle.net>
As in the gen_repz_scas/gen_repz_cmps case, delay setting
CC_OP_DYNAMIC in gen_jcc until after code generation. All of
gen_jcc1/is_fast_jcc/gen_setcc_slow_T0 now work on s->cc_op, which makes
things a bit easier to follow and to patch.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Richard Henderson <rth@twiddle.net>
Set it to the appropriate CC_OP_SUBx constant in gen_scas/gen_cmps.
In the repz case it can be overridden to CC_OP_DYNAMIC after generating
the code.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Richard Henderson <rth@twiddle.net>
Introduce a function that abstracts extracting an 8, 16, 32 or 64-bit value
with or without sign, generalizing gen_extu and gen_exts.
Reviewed-by: Blue Swirl <blauwirbel@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Richard Henderson <rth@twiddle.net>
Rename the public-facing function cpu_set_log to qemu_set_log. This
requires us to rename the internal-only qemu_set_log() to
do_qemu_set_log().
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
Pass around CPUArchState instead of using global cpu_single_env.
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
Reviewed-by: Andreas Färber <afaerber@suse.de>
