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Make pow2ceil() and pow2floor() inline 

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
This commit is contained in:
Peter Maydell 2015-07-24 13:33:12 +01:00
parent 10944a1920
commit 8f1ed5f508
3 changed files with 34 additions and 38 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
include/qemu-common.h
View File

@ -24,6 +24,7 @@
#include "glib-compat.h"
#include "qemu/option.h"
#include "qemu/host-utils.h"
/* HOST_LONG_BITS is the size of a native pointer in bits. */
#if UINTPTR_MAX == UINT32_MAX
@ -416,21 +417,6 @@ static inline uint8_t from_bcd(uint8_t val)
/* Round number up to multiple */
#define QEMU_ALIGN_UP(n, m) QEMU_ALIGN_DOWN((n) + (m) - 1, (m))
static inline bool is_power_of_2(uint64_t value)
{
if (!value) {
return 0;
}
return !(value & (value - 1));
}
/* round down to the nearest power of 2*/
int64_t pow2floor(int64_t value);
/* round up to the nearest power of 2 (0 if overflow) */
uint64_t pow2ceil(uint64_t value);
#include "qemu/module.h"
/*

33
include/qemu/host-utils.h
View File

@ -27,6 +27,7 @@
#include "qemu/compiler.h" /* QEMU_GNUC_PREREQ */
#include <limits.h>
#include <stdbool.h>
#ifdef CONFIG_INT128
static inline void mulu64(uint64_t *plow, uint64_t *phigh,
@ -408,4 +409,36 @@ static inline int ctpop64(uint64_t val)
# error Unknown sizeof long
#endif
static inline bool is_power_of_2(uint64_t value)
{
if (!value) {
return 0;
}
return !(value & (value - 1));
}
/* round down to the nearest power of 2*/
static inline int64_t pow2floor(int64_t value)
{
if (!is_power_of_2(value)) {
value = 0x8000000000000000ULL >> clz64(value);
}
return value;
}
/* round up to the nearest power of 2 (0 if overflow) */
static inline uint64_t pow2ceil(uint64_t value)
{
uint8_t nlz = clz64(value);
if (is_power_of_2(value)) {
return value;
}
if (!nlz) {
return 0;
}
return 1ULL << (64 - nlz);
}
#endif

23
util/cutils.c
View File

@ -469,29 +469,6 @@ int qemu_parse_fd(const char *param)
return fd;
}
/* round down to the nearest power of 2*/
int64_t pow2floor(int64_t value)
{
if (!is_power_of_2(value)) {
value = 0x8000000000000000ULL >> clz64(value);
}
return value;
}
/* round up to the nearest power of 2 (0 if overflow) */
uint64_t pow2ceil(uint64_t value)
{
uint8_t nlz = clz64(value);
if (is_power_of_2(value)) {
return value;
}
if (!nlz) {
return 0;
}
return 1ULL << (64 - nlz);
}
/*
* Implementation of ULEB128 (http://en.wikipedia.org/wiki/LEB128)
* Input is limited to 14-bit numbers