On 3/3/23 16:09, Jonathan Cameron wrote:
From: Ira Weiny <ira.we...@intel.com>
CXL has 24 bit unaligned fields which need to be stored to. CXL is
specified as little endian.
Define st24_le_p() and the supporting functions to store such a field
from a 32 bit host native value.
The use of b, w, l, q as the size specifier is limiting. So "24" was
used for the size part of the function name.
Reviewed-by: Fan Ni <fan...@samsung.com>
Signed-off-by: Ira Weiny <ira.we...@intel.com>
Signed-off-by: Jonathan Cameron <jonathan.came...@huawei.com>
---
v8:
- Picked up tag from Fan Ni.
---
include/qemu/bswap.h | 23 +++++++++++++++++++++++
1 file changed, 23 insertions(+)
diff --git a/include/qemu/bswap.h b/include/qemu/bswap.h
index 15a78c0db5..ee71cbeaaa 100644
--- a/include/qemu/bswap.h
+++ b/include/qemu/bswap.h
@@ -8,11 +8,23 @@
#undef bswap64
#define bswap64(_x) __builtin_bswap64(_x)
+static inline uint32_t bswap24(uint32_t x)
+{
Could it be safer to add:
assert(x & 0xff000000U == 0);
...
+ return (((x & 0x000000ffU) << 16) |
+ ((x & 0x0000ff00U) << 0) |
+ ((x & 0x00ff0000U) >> 16));
+}
+
static inline void bswap16s(uint16_t *s)
{
*s = __builtin_bswap16(*s);
}
+static inline void bswap24s(uint32_t *s)
+{
+ *s = bswap24(*s);
... and here use:
*s = bswap24(*s & 0x00ffffffU);
?
+}
+
static inline void bswap32s(uint32_t *s)
{
*s = __builtin_bswap32(*s);
@@ -176,6 +188,7 @@ CPU_CONVERT(le, 64, uint64_t)
* size is:
* b: 8 bits
* w: 16 bits
+ * 24: 24 bits
Following the pattern, shouldn't this be 's' for sēsquiword?
Regardless you need to update the doc in docs/devel/loads-stores.rst.
* l: 32 bits
* q: 64 bits
*
@@ -248,6 +261,11 @@ static inline void stw_he_p(void *ptr, uint16_t v)
__builtin_memcpy(ptr, &v, sizeof(v));
}
+static inline void st24_he_p(void *ptr, uint32_t v)
+{
+ __builtin_memcpy(ptr, &v, 3);
+}
+
static inline int ldl_he_p(const void *ptr)
{
int32_t r;
@@ -297,6 +315,11 @@ static inline void stw_le_p(void *ptr, uint16_t v)
stw_he_p(ptr, le_bswap(v, 16));
}
+static inline void st24_le_p(void *ptr, uint32_t v)
+{
+ st24_he_p(ptr, le_bswap(v, 24));
+}