bswap: Add new stn_*_p() and ldn_*_p() memory access functions

There's a common pattern in QEMU where a function needs to perform
a data load or store of an N byte integer in a particular endianness.
At the moment this is handled by doing a switch() on the size and
calling the appropriate ld*_p or st*_p function for each size.

Provide a new family of functions ldn_*_p() and stn_*_p() which
take the size as an argument and do the switch() themselves.

Backports commit afa4f6653dca095f63f3fe7f2001e9334f5676c1 from qemu
This commit is contained in:
Peter Maydell 2018-06-15 12:17:19 -04:00 committed by Lioncash
parent 61a7ac6948
commit 8295b228e3
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2 changed files with 64 additions and 0 deletions

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@ -166,6 +166,8 @@ static inline void tswap64s(uint64_t *s)
#define stq_p(p, v) stq_be_p(p, v) #define stq_p(p, v) stq_be_p(p, v)
#define stfl_p(p, v) stfl_be_p(p, v) #define stfl_p(p, v) stfl_be_p(p, v)
#define stfq_p(p, v) stfq_be_p(p, v) #define stfq_p(p, v) stfq_be_p(p, v)
#define ldn_p(p, sz) ldn_be_p(p, sz)
#define stn_p(p, sz, v) stn_be_p(p, sz, v)
#else #else
#define lduw_p(p) lduw_le_p(p) #define lduw_p(p) lduw_le_p(p)
#define ldsw_p(p) ldsw_le_p(p) #define ldsw_p(p) ldsw_le_p(p)
@ -178,6 +180,8 @@ static inline void tswap64s(uint64_t *s)
#define stq_p(p, v) stq_le_p(p, v) #define stq_p(p, v) stq_le_p(p, v)
#define stfl_p(p, v) stfl_le_p(p, v) #define stfl_p(p, v) stfl_le_p(p, v)
#define stfq_p(p, v) stfq_le_p(p, v) #define stfq_p(p, v) stfq_le_p(p, v)
#define ldn_p(p, sz) ldn_le_p(p, sz)
#define stn_p(p, sz, v) stn_le_p(p, sz, v)
#endif #endif
/* MMU memory access macros */ /* MMU memory access macros */

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@ -266,6 +266,23 @@ typedef union {
* be : big endian * be : big endian
* le : little endian * le : little endian
* (except for byte accesses, which have no endian infix). * (except for byte accesses, which have no endian infix).
*
* The target endian accessors are obviously only available to source
* files which are built per-target; they are defined in cpu-all.h.
*
* In all cases these functions take a host pointer.
* For accessors that take a guest address rather than a
* host address, see the cpu_{ld,st}_* accessors defined in
* cpu_ldst.h.
*
* For cases where the size to be used is not fixed at compile time,
* there are
* stn{endian}_p(ptr, sz, val)
* which stores @val to @ptr as an @endian-order number @sz bytes in size
* and
* ldn{endian}_p(ptr, sz)
* which loads @sz bytes from @ptr as an unsigned @endian-order number
* and returns it in a uint64_t.
*/ */
static inline int ldub_p(const void *ptr) static inline int ldub_p(const void *ptr)
@ -471,6 +488,49 @@ static inline unsigned long leul_to_cpu(unsigned long v)
#endif #endif
} }
/* Store v to p as a sz byte value in host order */
#define DO_STN_LDN_P(END) \
static inline void stn_## END ## _p(void *ptr, int sz, uint64_t v) \
{ \
switch (sz) { \
case 1: \
stb_p(ptr, v); \
break; \
case 2: \
stw_ ## END ## _p(ptr, v); \
break; \
case 4: \
stl_ ## END ## _p(ptr, v); \
break; \
case 8: \
stq_ ## END ## _p(ptr, v); \
break; \
default: \
g_assert_not_reached(); \
} \
} \
static inline uint64_t ldn_## END ## _p(const void *ptr, int sz) \
{ \
switch (sz) { \
case 1: \
return ldub_p(ptr); \
case 2: \
return lduw_ ## END ## _p(ptr); \
case 4: \
return (uint32_t)ldl_ ## END ## _p(ptr); \
case 8: \
return ldq_ ## END ## _p(ptr); \
default: \
g_assert_not_reached(); \
} \
}
DO_STN_LDN_P(he)
DO_STN_LDN_P(le)
DO_STN_LDN_P(be)
#undef DO_STN_LDN_P
#undef le_bswap #undef le_bswap
#undef be_bswap #undef be_bswap
#undef le_bswaps #undef le_bswaps