2007-10-27 15:05:54 +02:00
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/*
|
|
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* Utility compute operations used by translated code.
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*
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* Copyright (c) 2007 Thiemo Seufer
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* Copyright (c) 2007 Jocelyn Mayer
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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2016-06-29 15:29:06 +02:00
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2012-12-06 12:15:58 +01:00
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#ifndef HOST_UTILS_H
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2016-06-29 15:29:06 +02:00
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#define HOST_UTILS_H
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2007-10-27 15:05:54 +02:00
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|
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2015-09-14 22:00:34 +02:00
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#include "qemu/bswap.h"
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2008-06-06 00:55:54 +02:00
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2013-02-16 21:46:59 +01:00
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#ifdef CONFIG_INT128
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2009-08-16 10:03:26 +02:00
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static inline void mulu64(uint64_t *plow, uint64_t *phigh,
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|
uint64_t a, uint64_t b)
|
2007-11-04 03:24:58 +01:00
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|
{
|
2013-02-16 21:46:59 +01:00
|
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|
__uint128_t r = (__uint128_t)a * b;
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*plow = r;
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*phigh = r >> 64;
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2007-11-04 03:24:58 +01:00
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|
}
|
2013-02-16 21:46:59 +01:00
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2009-08-16 10:03:26 +02:00
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static inline void muls64(uint64_t *plow, uint64_t *phigh,
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int64_t a, int64_t b)
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2007-11-04 03:24:58 +01:00
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{
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2013-02-16 21:46:59 +01:00
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__int128_t r = (__int128_t)a * b;
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*plow = r;
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*phigh = r >> 64;
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2007-11-04 03:24:58 +01:00
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}
|
2014-01-07 17:05:51 +01:00
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2015-08-19 17:20:20 +02:00
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/* compute with 96 bit intermediate result: (a*b)/c */
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static inline uint64_t muldiv64(uint64_t a, uint32_t b, uint32_t c)
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|
|
{
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|
return (__int128_t)a * b / c;
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|
}
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|
2014-01-07 17:05:51 +01:00
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static inline int divu128(uint64_t *plow, uint64_t *phigh, uint64_t divisor)
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|
|
{
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|
|
|
if (divisor == 0) {
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|
return 1;
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|
|
} else {
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|
__uint128_t dividend = ((__uint128_t)*phigh << 64) | *plow;
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|
__uint128_t result = dividend / divisor;
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*plow = result;
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|
*phigh = dividend % divisor;
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|
|
|
return result > UINT64_MAX;
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|
|
|
}
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|
|
}
|
2014-01-07 17:05:52 +01:00
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|
|
static inline int divs128(int64_t *plow, int64_t *phigh, int64_t divisor)
|
|
|
|
{
|
|
|
|
if (divisor == 0) {
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|
|
|
return 1;
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|
|
|
} else {
|
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|
|
__int128_t dividend = ((__int128_t)*phigh << 64) | *plow;
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|
|
|
__int128_t result = dividend / divisor;
|
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|
|
*plow = result;
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|
|
|
*phigh = dividend % divisor;
|
|
|
|
return result != *plow;
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|
|
|
}
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|
|
|
}
|
2007-11-04 03:24:58 +01:00
|
|
|
#else
|
2020-07-02 01:43:44 +02:00
|
|
|
void muls64(uint64_t *plow, uint64_t *phigh, int64_t a, int64_t b);
|
|
|
|
void mulu64(uint64_t *plow, uint64_t *phigh, uint64_t a, uint64_t b);
|
2014-01-07 17:05:51 +01:00
|
|
|
int divu128(uint64_t *plow, uint64_t *phigh, uint64_t divisor);
|
2014-01-07 17:05:52 +01:00
|
|
|
int divs128(int64_t *plow, int64_t *phigh, int64_t divisor);
|
2015-08-19 17:20:20 +02:00
|
|
|
|
|
|
|
static inline uint64_t muldiv64(uint64_t a, uint32_t b, uint32_t c)
|
|
|
|
{
|
|
|
|
union {
|
|
|
|
uint64_t ll;
|
|
|
|
struct {
|
|
|
|
#ifdef HOST_WORDS_BIGENDIAN
|
|
|
|
uint32_t high, low;
|
|
|
|
#else
|
|
|
|
uint32_t low, high;
|
|
|
|
#endif
|
|
|
|
} l;
|
|
|
|
} u, res;
|
|
|
|
uint64_t rl, rh;
|
|
|
|
|
|
|
|
u.ll = a;
|
|
|
|
rl = (uint64_t)u.l.low * (uint64_t)b;
|
|
|
|
rh = (uint64_t)u.l.high * (uint64_t)b;
|
|
|
|
rh += (rl >> 32);
|
|
|
|
res.l.high = rh / c;
|
|
|
|
res.l.low = (((rh % c) << 32) + (rl & 0xffffffff)) / c;
|
|
|
|
return res.ll;
|
|
|
|
}
|
2007-11-04 03:24:58 +01:00
|
|
|
#endif
|
|
|
|
|
2013-02-14 02:47:35 +01:00
|
|
|
/**
|
|
|
|
* clz32 - count leading zeros in a 32-bit value.
|
|
|
|
* @val: The value to search
|
|
|
|
*
|
|
|
|
* Returns 32 if the value is zero. Note that the GCC builtin is
|
|
|
|
* undefined if the value is zero.
|
|
|
|
*/
|
2009-08-16 10:03:26 +02:00
|
|
|
static inline int clz32(uint32_t val)
|
2007-10-27 15:05:54 +02:00
|
|
|
{
|
2013-02-14 02:47:35 +01:00
|
|
|
return val ? __builtin_clz(val) : 32;
|
2007-10-27 15:05:54 +02:00
|
|
|
}
|
|
|
|
|
2013-02-14 02:47:35 +01:00
|
|
|
/**
|
|
|
|
* clo32 - count leading ones in a 32-bit value.
|
|
|
|
* @val: The value to search
|
|
|
|
*
|
|
|
|
* Returns 32 if the value is -1.
|
|
|
|
*/
|
2009-08-16 10:03:26 +02:00
|
|
|
static inline int clo32(uint32_t val)
|
2007-10-27 15:05:54 +02:00
|
|
|
{
|
|
|
|
return clz32(~val);
|
|
|
|
}
|
|
|
|
|
2013-02-14 02:47:35 +01:00
|
|
|
/**
|
|
|
|
* clz64 - count leading zeros in a 64-bit value.
|
|
|
|
* @val: The value to search
|
|
|
|
*
|
|
|
|
* Returns 64 if the value is zero. Note that the GCC builtin is
|
|
|
|
* undefined if the value is zero.
|
|
|
|
*/
|
2009-08-16 10:03:26 +02:00
|
|
|
static inline int clz64(uint64_t val)
|
2007-10-27 15:05:54 +02:00
|
|
|
{
|
2013-02-14 02:47:35 +01:00
|
|
|
return val ? __builtin_clzll(val) : 64;
|
2007-10-27 15:05:54 +02:00
|
|
|
}
|
|
|
|
|
2013-02-14 02:47:35 +01:00
|
|
|
/**
|
|
|
|
* clo64 - count leading ones in a 64-bit value.
|
|
|
|
* @val: The value to search
|
|
|
|
*
|
|
|
|
* Returns 64 if the value is -1.
|
|
|
|
*/
|
2009-08-16 10:03:26 +02:00
|
|
|
static inline int clo64(uint64_t val)
|
2007-10-27 15:05:54 +02:00
|
|
|
{
|
|
|
|
return clz64(~val);
|
|
|
|
}
|
2007-10-28 13:52:38 +01:00
|
|
|
|
2013-02-14 02:47:35 +01:00
|
|
|
/**
|
|
|
|
* ctz32 - count trailing zeros in a 32-bit value.
|
|
|
|
* @val: The value to search
|
|
|
|
*
|
|
|
|
* Returns 32 if the value is zero. Note that the GCC builtin is
|
|
|
|
* undefined if the value is zero.
|
|
|
|
*/
|
2009-08-16 10:03:26 +02:00
|
|
|
static inline int ctz32(uint32_t val)
|
2007-10-28 13:52:38 +01:00
|
|
|
{
|
2013-02-14 02:47:35 +01:00
|
|
|
return val ? __builtin_ctz(val) : 32;
|
2008-11-12 18:18:41 +01:00
|
|
|
}
|
|
|
|
|
2013-02-14 02:47:35 +01:00
|
|
|
/**
|
|
|
|
* cto32 - count trailing ones in a 32-bit value.
|
|
|
|
* @val: The value to search
|
|
|
|
*
|
|
|
|
* Returns 32 if the value is -1.
|
|
|
|
*/
|
2009-08-16 10:03:26 +02:00
|
|
|
static inline int cto32(uint32_t val)
|
2008-11-12 18:18:41 +01:00
|
|
|
{
|
2007-10-28 13:52:38 +01:00
|
|
|
return ctz32(~val);
|
|
|
|
}
|
|
|
|
|
2013-02-14 02:47:35 +01:00
|
|
|
/**
|
|
|
|
* ctz64 - count trailing zeros in a 64-bit value.
|
|
|
|
* @val: The value to search
|
|
|
|
*
|
|
|
|
* Returns 64 if the value is zero. Note that the GCC builtin is
|
|
|
|
* undefined if the value is zero.
|
|
|
|
*/
|
2009-08-16 10:03:26 +02:00
|
|
|
static inline int ctz64(uint64_t val)
|
2007-10-28 13:52:38 +01:00
|
|
|
{
|
2013-02-14 02:47:35 +01:00
|
|
|
return val ? __builtin_ctzll(val) : 64;
|
2007-10-28 13:52:38 +01:00
|
|
|
}
|
|
|
|
|
2013-02-14 02:47:35 +01:00
|
|
|
/**
|
2014-02-12 18:14:33 +01:00
|
|
|
* cto64 - count trailing ones in a 64-bit value.
|
2013-02-14 02:47:35 +01:00
|
|
|
* @val: The value to search
|
|
|
|
*
|
|
|
|
* Returns 64 if the value is -1.
|
|
|
|
*/
|
2009-08-16 10:03:26 +02:00
|
|
|
static inline int cto64(uint64_t val)
|
2007-10-28 13:52:38 +01:00
|
|
|
{
|
|
|
|
return ctz64(~val);
|
|
|
|
}
|
|
|
|
|
2013-12-17 20:42:35 +01:00
|
|
|
/**
|
|
|
|
* clrsb32 - count leading redundant sign bits in a 32-bit value.
|
|
|
|
* @val: The value to search
|
|
|
|
*
|
|
|
|
* Returns the number of bits following the sign bit that are equal to it.
|
|
|
|
* No special cases; output range is [0-31].
|
|
|
|
*/
|
|
|
|
static inline int clrsb32(uint32_t val)
|
|
|
|
{
|
2018-12-03 14:33:12 +01:00
|
|
|
#if __has_builtin(__builtin_clrsb) || !defined(__clang__)
|
2013-12-17 20:42:35 +01:00
|
|
|
return __builtin_clrsb(val);
|
|
|
|
#else
|
|
|
|
return clz32(val ^ ((int32_t)val >> 1)) - 1;
|
|
|
|
#endif
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* clrsb64 - count leading redundant sign bits in a 64-bit value.
|
|
|
|
* @val: The value to search
|
|
|
|
*
|
|
|
|
* Returns the number of bits following the sign bit that are equal to it.
|
|
|
|
* No special cases; output range is [0-63].
|
|
|
|
*/
|
|
|
|
static inline int clrsb64(uint64_t val)
|
|
|
|
{
|
2018-12-03 14:33:12 +01:00
|
|
|
#if __has_builtin(__builtin_clrsbll) || !defined(__clang__)
|
2013-12-17 20:42:35 +01:00
|
|
|
return __builtin_clrsbll(val);
|
|
|
|
#else
|
|
|
|
return clz64(val ^ ((int64_t)val >> 1)) - 1;
|
|
|
|
#endif
|
|
|
|
}
|
|
|
|
|
2013-02-14 02:47:35 +01:00
|
|
|
/**
|
|
|
|
* ctpop8 - count the population of one bits in an 8-bit value.
|
|
|
|
* @val: The value to search
|
|
|
|
*/
|
2009-08-16 10:03:26 +02:00
|
|
|
static inline int ctpop8(uint8_t val)
|
2007-10-28 13:52:38 +01:00
|
|
|
{
|
2013-02-14 02:47:35 +01:00
|
|
|
return __builtin_popcount(val);
|
2007-10-28 13:52:38 +01:00
|
|
|
}
|
|
|
|
|
2013-02-14 02:47:35 +01:00
|
|
|
/**
|
|
|
|
* ctpop16 - count the population of one bits in a 16-bit value.
|
|
|
|
* @val: The value to search
|
|
|
|
*/
|
2009-08-16 10:03:26 +02:00
|
|
|
static inline int ctpop16(uint16_t val)
|
2007-10-28 13:52:38 +01:00
|
|
|
{
|
2013-02-14 02:47:35 +01:00
|
|
|
return __builtin_popcount(val);
|
2007-10-28 13:52:38 +01:00
|
|
|
}
|
|
|
|
|
2013-02-14 02:47:35 +01:00
|
|
|
/**
|
|
|
|
* ctpop32 - count the population of one bits in a 32-bit value.
|
|
|
|
* @val: The value to search
|
|
|
|
*/
|
2009-08-16 10:03:26 +02:00
|
|
|
static inline int ctpop32(uint32_t val)
|
2007-10-28 13:52:38 +01:00
|
|
|
{
|
2008-10-12 02:53:08 +02:00
|
|
|
return __builtin_popcount(val);
|
2007-10-28 13:52:38 +01:00
|
|
|
}
|
|
|
|
|
2013-02-14 02:47:35 +01:00
|
|
|
/**
|
|
|
|
* ctpop64 - count the population of one bits in a 64-bit value.
|
|
|
|
* @val: The value to search
|
|
|
|
*/
|
2009-08-16 10:03:26 +02:00
|
|
|
static inline int ctpop64(uint64_t val)
|
2007-10-28 13:52:38 +01:00
|
|
|
{
|
2008-10-12 02:53:08 +02:00
|
|
|
return __builtin_popcountll(val);
|
2007-12-18 02:58:05 +01:00
|
|
|
}
|
2012-12-06 12:15:58 +01:00
|
|
|
|
2015-09-14 22:00:34 +02:00
|
|
|
/**
|
|
|
|
* revbit8 - reverse the bits in an 8-bit value.
|
|
|
|
* @x: The value to modify.
|
|
|
|
*/
|
|
|
|
static inline uint8_t revbit8(uint8_t x)
|
|
|
|
{
|
|
|
|
/* Assign the correct nibble position. */
|
|
|
|
x = ((x & 0xf0) >> 4)
|
|
|
|
| ((x & 0x0f) << 4);
|
|
|
|
/* Assign the correct bit position. */
|
|
|
|
x = ((x & 0x88) >> 3)
|
|
|
|
| ((x & 0x44) >> 1)
|
|
|
|
| ((x & 0x22) << 1)
|
|
|
|
| ((x & 0x11) << 3);
|
|
|
|
return x;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* revbit16 - reverse the bits in a 16-bit value.
|
|
|
|
* @x: The value to modify.
|
|
|
|
*/
|
|
|
|
static inline uint16_t revbit16(uint16_t x)
|
|
|
|
{
|
|
|
|
/* Assign the correct byte position. */
|
|
|
|
x = bswap16(x);
|
|
|
|
/* Assign the correct nibble position. */
|
|
|
|
x = ((x & 0xf0f0) >> 4)
|
|
|
|
| ((x & 0x0f0f) << 4);
|
|
|
|
/* Assign the correct bit position. */
|
|
|
|
x = ((x & 0x8888) >> 3)
|
|
|
|
| ((x & 0x4444) >> 1)
|
|
|
|
| ((x & 0x2222) << 1)
|
|
|
|
| ((x & 0x1111) << 3);
|
|
|
|
return x;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* revbit32 - reverse the bits in a 32-bit value.
|
|
|
|
* @x: The value to modify.
|
|
|
|
*/
|
|
|
|
static inline uint32_t revbit32(uint32_t x)
|
|
|
|
{
|
|
|
|
/* Assign the correct byte position. */
|
|
|
|
x = bswap32(x);
|
|
|
|
/* Assign the correct nibble position. */
|
|
|
|
x = ((x & 0xf0f0f0f0u) >> 4)
|
|
|
|
| ((x & 0x0f0f0f0fu) << 4);
|
|
|
|
/* Assign the correct bit position. */
|
|
|
|
x = ((x & 0x88888888u) >> 3)
|
|
|
|
| ((x & 0x44444444u) >> 1)
|
|
|
|
| ((x & 0x22222222u) << 1)
|
|
|
|
| ((x & 0x11111111u) << 3);
|
|
|
|
return x;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* revbit64 - reverse the bits in a 64-bit value.
|
|
|
|
* @x: The value to modify.
|
|
|
|
*/
|
|
|
|
static inline uint64_t revbit64(uint64_t x)
|
|
|
|
{
|
|
|
|
/* Assign the correct byte position. */
|
|
|
|
x = bswap64(x);
|
|
|
|
/* Assign the correct nibble position. */
|
|
|
|
x = ((x & 0xf0f0f0f0f0f0f0f0ull) >> 4)
|
|
|
|
| ((x & 0x0f0f0f0f0f0f0f0full) << 4);
|
|
|
|
/* Assign the correct bit position. */
|
|
|
|
x = ((x & 0x8888888888888888ull) >> 3)
|
|
|
|
| ((x & 0x4444444444444444ull) >> 1)
|
|
|
|
| ((x & 0x2222222222222222ull) << 1)
|
|
|
|
| ((x & 0x1111111111111111ull) << 3);
|
|
|
|
return x;
|
|
|
|
}
|
|
|
|
|
2013-02-14 02:47:34 +01:00
|
|
|
/* Host type specific sizes of these routines. */
|
|
|
|
|
|
|
|
#if ULONG_MAX == UINT32_MAX
|
|
|
|
# define clzl clz32
|
|
|
|
# define ctzl ctz32
|
|
|
|
# define clol clo32
|
|
|
|
# define ctol cto32
|
|
|
|
# define ctpopl ctpop32
|
2015-09-14 22:00:34 +02:00
|
|
|
# define revbitl revbit32
|
2013-02-14 02:47:34 +01:00
|
|
|
#elif ULONG_MAX == UINT64_MAX
|
|
|
|
# define clzl clz64
|
|
|
|
# define ctzl ctz64
|
|
|
|
# define clol clo64
|
|
|
|
# define ctol cto64
|
|
|
|
# define ctpopl ctpop64
|
2015-09-14 22:00:34 +02:00
|
|
|
# define revbitl revbit64
|
2013-02-14 02:47:34 +01:00
|
|
|
#else
|
|
|
|
# error Unknown sizeof long
|
|
|
|
#endif
|
|
|
|
|
2015-07-24 14:33:12 +02:00
|
|
|
static inline bool is_power_of_2(uint64_t value)
|
|
|
|
{
|
|
|
|
if (!value) {
|
2016-05-31 20:33:31 +02:00
|
|
|
return false;
|
2015-07-24 14:33:12 +02:00
|
|
|
}
|
|
|
|
|
|
|
|
return !(value & (value - 1));
|
|
|
|
}
|
|
|
|
|
host-utils: Proactively fix pow2floor(), switch to unsigned
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>
2017-07-27 11:46:15 +02:00
|
|
|
/**
|
|
|
|
* Return @value rounded down to the nearest power of two or zero.
|
|
|
|
*/
|
|
|
|
static inline uint64_t pow2floor(uint64_t value)
|
2015-07-24 14:33:12 +02:00
|
|
|
{
|
host-utils: Proactively fix pow2floor(), switch to unsigned
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>
2017-07-27 11:46:15 +02:00
|
|
|
if (!value) {
|
|
|
|
/* Avoid undefined shift by 64 */
|
|
|
|
return 0;
|
2015-07-24 14:33:12 +02:00
|
|
|
}
|
host-utils: Proactively fix pow2floor(), switch to unsigned
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>
2017-07-27 11:46:15 +02:00
|
|
|
return 0x8000000000000000ull >> clz64(value);
|
2015-07-24 14:33:12 +02:00
|
|
|
}
|
|
|
|
|
2017-07-27 11:46:16 +02:00
|
|
|
/*
|
|
|
|
* Return @value rounded up to the nearest power of two modulo 2^64.
|
|
|
|
* This is *zero* for @value > 2^63, so be careful.
|
|
|
|
*/
|
2015-07-24 14:33:12 +02:00
|
|
|
static inline uint64_t pow2ceil(uint64_t value)
|
|
|
|
{
|
2017-07-27 11:46:16 +02:00
|
|
|
int n = clz64(value - 1);
|
|
|
|
|
|
|
|
if (!n) {
|
|
|
|
/*
|
|
|
|
* @value - 1 has no leading zeroes, thus @value - 1 >= 2^63
|
|
|
|
* Therefore, either @value == 0 or @value > 2^63.
|
|
|
|
* If it's 0, return 1, else return 0.
|
|
|
|
*/
|
|
|
|
return !value;
|
2015-07-24 14:33:12 +02:00
|
|
|
}
|
2017-07-27 11:46:16 +02:00
|
|
|
return 0x8000000000000000ull >> (n - 1);
|
2015-07-24 14:33:12 +02:00
|
|
|
}
|
|
|
|
|
2018-01-14 10:01:43 +01:00
|
|
|
static inline uint32_t pow2roundup32(uint32_t x)
|
|
|
|
{
|
|
|
|
x |= (x >> 1);
|
|
|
|
x |= (x >> 2);
|
|
|
|
x |= (x >> 4);
|
|
|
|
x |= (x >> 8);
|
|
|
|
x |= (x >> 16);
|
|
|
|
return x + 1;
|
|
|
|
}
|
|
|
|
|
2017-01-10 03:10:09 +01:00
|
|
|
/**
|
|
|
|
* urshift - 128-bit Unsigned Right Shift.
|
|
|
|
* @plow: in/out - lower 64-bit integer.
|
|
|
|
* @phigh: in/out - higher 64-bit integer.
|
|
|
|
* @shift: in - bytes to shift, between 0 and 127.
|
|
|
|
*
|
|
|
|
* Result is zero-extended and stored in plow/phigh, which are
|
|
|
|
* input/output variables. Shift values outside the range will
|
|
|
|
* be mod to 128. In other words, the caller is responsible to
|
|
|
|
* verify/assert both the shift range and plow/phigh pointers.
|
|
|
|
*/
|
|
|
|
void urshift(uint64_t *plow, uint64_t *phigh, int32_t shift);
|
|
|
|
|
|
|
|
/**
|
|
|
|
* ulshift - 128-bit Unsigned Left Shift.
|
|
|
|
* @plow: in/out - lower 64-bit integer.
|
|
|
|
* @phigh: in/out - higher 64-bit integer.
|
|
|
|
* @shift: in - bytes to shift, between 0 and 127.
|
|
|
|
* @overflow: out - true if any 1-bit is shifted out.
|
|
|
|
*
|
|
|
|
* Result is zero-extended and stored in plow/phigh, which are
|
|
|
|
* input/output variables. Shift values outside the range will
|
|
|
|
* be mod to 128. In other words, the caller is responsible to
|
|
|
|
* verify/assert both the shift range and plow/phigh pointers.
|
|
|
|
*/
|
|
|
|
void ulshift(uint64_t *plow, uint64_t *phigh, int32_t shift, bool *overflow);
|
|
|
|
|
2012-12-06 12:15:58 +01:00
|
|
|
#endif
|