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authorPeter Maydell <peter.maydell@linaro.org>2018-06-15 14:57:14 +0100
committerPeter Maydell <peter.maydell@linaro.org>2018-06-15 15:23:34 +0100
commitafa4f6653dca095f63f3fe7f2001e9334f5676c1 (patch)
tree5d3b9c27711a2b3ef5eaa2635593921092e32ae9 /include/qemu
parent2948f0cde3974185ad22d6721438cf85df852877 (diff)
downloadfocaccia-qemu-afa4f6653dca095f63f3fe7f2001e9334f5676c1.tar.gz
focaccia-qemu-afa4f6653dca095f63f3fe7f2001e9334f5676c1.zip
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.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20180611171007.4165-2-peter.maydell@linaro.org
Diffstat (limited to 'include/qemu')
-rw-r--r--include/qemu/bswap.h52
1 files changed, 52 insertions, 0 deletions
diff --git a/include/qemu/bswap.h b/include/qemu/bswap.h
index 3f28f661b1..a684c1a7a2 100644
--- a/include/qemu/bswap.h
+++ b/include/qemu/bswap.h
@@ -290,6 +290,15 @@ typedef union {
  * 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)
@@ -495,6 +504,49 @@ static inline unsigned long leul_to_cpu(unsigned long v)
 #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 be_bswap
 #undef le_bswaps