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include/exec: Provide the tswap() functions for target independent code, too

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In some cases of target independent code, it would be useful to have access
to the functions that swap endianess in case it differs between guest and
host. Thus re-implement the tswapXX() functions in a new header that can be
included separately. The check whether the swapping is needed continues to
be done at compile-time for target specific code, while it is done at
run-time in target-independent code.

Message-Id: <20230411183418.1640500-3-thuth@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Thomas Huth <thuth@redhat.com>
This commit is contained in:
Thomas Huth 2023-04-11 20:34:17 +02:00
parent c7a6bf5d92
commit 24be3369ad
2 changed files with 73 additions and 63 deletions
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64
include/exec/cpu-all.h
View File

@ -21,6 +21,7 @@
#include "exec/cpu-common.h"
#include "exec/memory.h"
#include "exec/tswap.h"
#include "qemu/thread.h"
#include "hw/core/cpu.h"
#include "qemu/rcu.h"
@ -44,69 +45,6 @@
#define BSWAP_NEEDED
#endif
#ifdef BSWAP_NEEDED
static inline uint16_t tswap16(uint16_t s)
{
return bswap16(s);
}
static inline uint32_t tswap32(uint32_t s)
{
return bswap32(s);
}
static inline uint64_t tswap64(uint64_t s)
{
return bswap64(s);
}
static inline void tswap16s(uint16_t *s)
{
*s = bswap16(*s);
}
static inline void tswap32s(uint32_t *s)
{
*s = bswap32(*s);
}
static inline void tswap64s(uint64_t *s)
{
*s = bswap64(*s);
}
#else
static inline uint16_t tswap16(uint16_t s)
{
return s;
}
static inline uint32_t tswap32(uint32_t s)
{
return s;
}
static inline uint64_t tswap64(uint64_t s)
{
return s;
}
static inline void tswap16s(uint16_t *s)
{
}
static inline void tswap32s(uint32_t *s)
{
}
static inline void tswap64s(uint64_t *s)
{
}
#endif
#if TARGET_LONG_SIZE == 4
#define tswapl(s) tswap32(s)
#define tswapls(s) tswap32s((uint32_t *)(s))

72
include/exec/tswap.h Normal file
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@ -0,0 +1,72 @@
/*
* Macros for swapping a value if the endianness is different
* between the target and the host.
*
* SPDX-License-Identifier: LGPL-2.1-or-later
*/
#ifndef TSWAP_H
#define TSWAP_H
#include "hw/core/cpu.h"
#include "qemu/bswap.h"
/*
* If we're in target-specific code, we can hard-code the swapping
* condition, otherwise we have to do (slower) run-time checks.
*/
#ifdef NEED_CPU_H
#define target_needs_bswap() (HOST_BIG_ENDIAN != TARGET_BIG_ENDIAN)
#else
#define target_needs_bswap() (target_words_bigendian() != HOST_BIG_ENDIAN)
#endif
static inline uint16_t tswap16(uint16_t s)
{
if (target_needs_bswap()) {
return bswap16(s);
} else {
return s;
}
}
static inline uint32_t tswap32(uint32_t s)
{
if (target_needs_bswap()) {
return bswap32(s);
} else {
return s;
}
}
static inline uint64_t tswap64(uint64_t s)
{
if (target_needs_bswap()) {
return bswap64(s);
} else {
return s;
}
}
static inline void tswap16s(uint16_t *s)
{
if (target_needs_bswap()) {
*s = bswap16(*s);
}
}
static inline void tswap32s(uint32_t *s)
{
if (target_needs_bswap()) {
*s = bswap32(*s);
}
}
static inline void tswap64s(uint64_t *s)
{
if (target_needs_bswap()) {
*s = bswap64(*s);
}
}
#endif /* TSWAP_H */