qemu-e2k/include/qemu/host-utils.h

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/*
* Utility compute operations used by translated code.
*
* Copyright (c) 2007 Thiemo Seufer
* Copyright (c) 2007 Jocelyn Mayer
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#ifndef HOST_UTILS_H
#define HOST_UTILS_H
#include "qemu/bswap.h"
#ifdef CONFIG_INT128
static inline void mulu64(uint64_t *plow, uint64_t *phigh,
uint64_t a, uint64_t b)
{
__uint128_t r = (__uint128_t)a * b;
*plow = r;
*phigh = r >> 64;
}
static inline void muls64(uint64_t *plow, uint64_t *phigh,
int64_t a, int64_t b)
{
__int128_t r = (__int128_t)a * b;
*plow = r;
*phigh = r >> 64;
}
/* compute with 96 bit intermediate result: (a*b)/c */
static inline uint64_t muldiv64(uint64_t a, uint32_t b, uint32_t c)
{
return (__int128_t)a * b / c;
}
static inline int divu128(uint64_t *plow, uint64_t *phigh, uint64_t divisor)
{
if (divisor == 0) {
return 1;
} else {
__uint128_t dividend = ((__uint128_t)*phigh << 64) | *plow;
__uint128_t result = dividend / divisor;
*plow = result;
*phigh = dividend % divisor;
return result > UINT64_MAX;
}
}
static inline int divs128(int64_t *plow, int64_t *phigh, int64_t divisor)
{
if (divisor == 0) {
return 1;
} else {
__int128_t dividend = ((__int128_t)*phigh << 64) | *plow;
__int128_t result = dividend / divisor;
*plow = result;
*phigh = dividend % divisor;
return result != *plow;
}
}
#else
void muls64(uint64_t *phigh, uint64_t *plow, int64_t a, int64_t b);
void mulu64(uint64_t *phigh, uint64_t *plow, uint64_t a, uint64_t b);
int divu128(uint64_t *plow, uint64_t *phigh, uint64_t divisor);
int divs128(int64_t *plow, int64_t *phigh, int64_t divisor);
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;
}
#endif
/**
* 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.
*/
static inline int clz32(uint32_t val)
{
return val ? __builtin_clz(val) : 32;
}
/**
* clo32 - count leading ones in a 32-bit value.
* @val: The value to search
*
* Returns 32 if the value is -1.
*/
static inline int clo32(uint32_t val)
{
return clz32(~val);
}
/**
* 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.
*/
static inline int clz64(uint64_t val)
{
return val ? __builtin_clzll(val) : 64;
}
/**
* clo64 - count leading ones in a 64-bit value.
* @val: The value to search
*
* Returns 64 if the value is -1.
*/
static inline int clo64(uint64_t val)
{
return clz64(~val);
}
/**
* 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.
*/
static inline int ctz32(uint32_t val)
{
return val ? __builtin_ctz(val) : 32;
}
/**
* cto32 - count trailing ones in a 32-bit value.
* @val: The value to search
*
* Returns 32 if the value is -1.
*/
static inline int cto32(uint32_t val)
{
return ctz32(~val);
}
/**
* 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.
*/
static inline int ctz64(uint64_t val)
{
return val ? __builtin_ctzll(val) : 64;
}
/**
* cto64 - count trailing ones in a 64-bit value.
* @val: The value to search
*
* Returns 64 if the value is -1.
*/
static inline int cto64(uint64_t val)
{
return ctz64(~val);
}
/**
* 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)
{
#if __has_builtin(__builtin_clrsb) || !defined(__clang__)
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)
{
#if __has_builtin(__builtin_clrsbll) || !defined(__clang__)
return __builtin_clrsbll(val);
#else
return clz64(val ^ ((int64_t)val >> 1)) - 1;
#endif
}
/**
* ctpop8 - count the population of one bits in an 8-bit value.
* @val: The value to search
*/
static inline int ctpop8(uint8_t val)
{
return __builtin_popcount(val);
}
/**
* ctpop16 - count the population of one bits in a 16-bit value.
* @val: The value to search
*/
static inline int ctpop16(uint16_t val)
{
return __builtin_popcount(val);
}
/**
* ctpop32 - count the population of one bits in a 32-bit value.
* @val: The value to search
*/
static inline int ctpop32(uint32_t val)
{
return __builtin_popcount(val);
}
/**
* ctpop64 - count the population of one bits in a 64-bit value.
* @val: The value to search
*/
static inline int ctpop64(uint64_t val)
{
return __builtin_popcountll(val);
}
/**
* 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;
}
/* 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
# define revbitl revbit32
#elif ULONG_MAX == UINT64_MAX
# define clzl clz64
# define ctzl ctz64
# define clol clo64
# define ctol cto64
# define ctpopl ctpop64
# define revbitl revbit64
#else
# error Unknown sizeof long
#endif
static inline bool is_power_of_2(uint64_t value)
{
if (!value) {
return false;
}
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)
{
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;
}
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);
}
/*
* Return @value rounded up to the nearest power of two modulo 2^64.
* This is *zero* for @value > 2^63, so be careful.
*/
static inline uint64_t pow2ceil(uint64_t value)
{
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;
}
return 0x8000000000000000ull >> (n - 1);
}
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;
}
/**
* 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);
#endif