Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <1501148776-16890-4-git-send-email-armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
The function's stated contract is simple enough: "round down to the
nearest power of 2". Suggests the domain is the representable numbers
>= 1, because that's the smallest power of two.
The implementation doesn't check for domain errors, but returns
garbage instead:
* For negative arguments, pow2floor() returns -2^63, which is not even
a power of two, let alone the nearest one.
What sort of works is passing *unsigned* arguments >= 2^63. The
implicit conversion to signed is implementation defined, but
commonly yields the (negative) two's complement. pow2floor() then
returns -2^63. Callers that convert that back to unsigned get the
correct value 2^63.
* For a zero argument, pow2floor() shifts right by 64. Undefined
behavior. Common actual behavior is to shift by 0, yielding -2^63.
Fix by switching from int64_t to uint64_t and amending the contract to
map zero to zero.
Callers are fine with that:
* memory_access_size()
This function makes no sense unless the argument is positive and the
return value fits into int.
* raw_refresh_limits()
Passes an int between 1 and BDRV_REQUEST_MAX_BYTES.
* iscsi_refresh_limits()
Passes an integer between 0 and INT_MAX, converts the result to
uint32_t. Passing zero would be undefined behavior, but commonly
yield zero. The patch gives us the zero without the undefined
behavior.
* cache_init()
Passes a positive int64_t argument.
* xbzrle_cache_resize()
Passes a positive int64_t argument (>= TARGET_PAGE_SIZE, actually).
* spapr_node0_size()
Passes a positive uint64_t argument, and converts the result to
hwaddr, i.e. uint64_t.
* spapr_populate_memory()
Passes a positive hwaddr argument, and converts the result to
hwaddr.
Cc: Juan Quintela <quintela@redhat.com>
Cc: Dr. David Alan Gilbert <dgilbert@redhat.com>
Cc: Eric Blake <eblake@redhat.com>
Cc: Peter Maydell <peter.maydell@linaro.org>
Cc: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <1501148776-16890-3-git-send-email-armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
We already require gcc 4.1 or newer (for the atomic
support), so the fallback codepaths for older gcc
versions than that are now dead code and we can
just delete them.
NB: clang reports itself as gcc 4.2 (regardless of
clang version), so clang won't be using the fallbacks
either.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Implements 128-bit left shift and right shift as well as their
testcases. By design, shift silently mods by 128, so the caller is
responsible to assert the shift range if necessary.
Left shift sets the overflow flag if any non-zero digit is shifted out.
Examples:
ulshift(&low, &high, 250, &overflow);
equivalent: n << 122
urshift(&low, &high, -2);
equivalent: n << 126
Signed-off-by: Jose Ricardo Ziviani <joserz@linux.vnet.ibm.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
[dwg: Added test-shift128 to .gitignore]
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Clean up includes so that osdep.h is included first and headers
which it implies are not included manually.
This commit was created with scripts/clean-includes.
NB: If this commit breaks compilation for your out-of-tree
patchseries or fork, then you need to make sure you add
#include "qemu/osdep.h" to any new .c files that you have.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
Since the pow2floor() function is now used in a hot code path,
make it inline; for consistency, provide pow2ceil() as an inline
function too.
Because these functions use ctz64() we have to put the inline
versions into host-utils.h, so they have access to ctz64(),
and move the inline is_power_of_2() along with them.
We then need to include host-utils.h from qemu-common.h so that
the files which use these functions via qemu-common.h still have
access to them.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 1437741192-20955-7-git-send-email-peter.maydell@linaro.org
Move the muldiv64() function from qemu-common.h to host-utils.h.
This puts it together with all the other arithmetic functions
where we provide a version with __int128_t and a fallback
without, and allows headers which need muldiv64() to avoid
including qemu-common.h.
We don't include host-utils from qemu-common.h, to avoid dragging
more things into qemu-common.h than it already has; in practice
everywhere that needs muldiv64() can get it via qemu/timer.h.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
This patch adds the Divide Doubleword Extended instructions.
The implementation builds on the unsigned helper provided in
the previous patch.
Signed-off-by: Tom Musta <tommusta@gmail.com>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Alexander Graf <agraf@suse.de>
This patch adds the Divide Doubleword Extended Unsigned
instructions. This instruction requires dividing a 128-bit
value by a 64 bit value. Since 128 bit integer division is
not supported in TCG, a helper is used. An architecture
independent 128-bit division routine is added to host-utils.
Signed-off-by: Tom Musta <tommusta@gmail.com>
Reviewed-by: Richard Henderson <rth@twiddle.net>
[agraf: use ||]
Signed-off-by: Alexander Graf <agraf@suse.de>
this patch introduces wrappers for the clrsb builtins,
which count the leading redundant sign bits.
Signed-off-by: Claudio Fontana <claudio.fontana@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Replace some x86_64 specific inline assembly with something that
all 64-bit hosts ought to optimize well. At worst this becomes
a call to the gcc __multi3 routine, which is no worse than our
implementation in util/host-utils.c.
With gcc 4.7, we get identical code generation for x86_64. We
now get native multiplication on ia64 and s390x hosts. With minor
improvements to gcc we can get it for ppc64 as well.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
Add function comments to the routines, documenting the corner
cases upon which we are standardizing. Fix the few instances
of non-standard coding style.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
We will standardize on these names, rather than the similar routines
currently residing in qemu/bitops.h.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
We had two copies of a ffs function for longs with subtly different
semantics and, for the one in bitops.h, a confusing name: the result
was off-by-one compared to the library function ffsl.
Unify the functions into one, and solve the name problem by calling
the 0-based functions "bitops_ctzl" and "bitops_ctol" respectively.
This also fixes the build on platforms with ffsl, including Mac OS X
and Windows.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Tested-by: Andreas Färber <afaerber@suse.de>
Tested-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
We can provide fast versions based on the other functions defined
by host-utils.h. Some care is required on glibc, which provides
ffsl already.
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
