X-Git-Url: https://codewiz.org/gitweb?a=blobdiff_plain;f=bertos%2Fcpu%2Fbyteorder.h;h=37d7a84167d97b24d3da9e150f878f461f207b97;hb=e8b0472be10fba4ca6baa62d8d483db90e28c06e;hp=b560559c4342f95cfe49c3c3bda698f19459c1cb;hpb=5117c025ff3e6cee6e0b934ff4cde205ccb34685;p=bertos.git

diff --git a/bertos/cpu/byteorder.h b/bertos/cpu/byteorder.h
index b560559c..37d7a841 100644
--- a/bertos/cpu/byteorder.h
+++ b/bertos/cpu/byteorder.h
@@ -40,6 +40,9 @@
 
 #include <cfg/compiler.h>
 #include <cpu/attr.h>
+#include <cpu/detect.h>
+#include <cpu/types.h>
+#include <cfg/macros.h>
 
 /**
  * Swap upper and lower bytes in a 16-bit value.
@@ -47,22 +50,27 @@
 #define SWAB16(x) ((uint16_t)(ROTR((x), 8) + \
 		STATIC_ASSERT_EXPR(sizeof(x) == sizeof(uint16_t))))
 
-#if GNUC_PREREQ(4, 3)
+/*
+ * On Cortex-M3, GCC 4.4 builtin implementation is slower than our own
+ * rot-based implementation.
+ */
+#if GNUC_PREREQ(4, 3) && !CPU_CM3
 #define SWAB32(x) ((uint32_t)(__builtin_bswap32((x) + \
 		STATIC_ASSERT_EXPR(sizeof(x) == sizeof(uint32_t)))))
-#define SWAB64(x) ((uint64_t)(__builtin_bswap64((x) + \
-		STATIC_ASSERT_EXPR(sizeof(x) == sizeof(uint64_t)))))
 #else
 /**
  * Reverse bytes in a 32-bit value (e.g.: 0x12345678 -> 0x78563412).
  */
-#define SWAB32(x) ((uint32_t)(						\
-	(((uint32_t)(x) & (uint32_t)0x000000ffUL) << 24) |		\
-	(((uint32_t)(x) & (uint32_t)0x0000ff00UL) <<  8) |		\
-	(((uint32_t)(x) & (uint32_t)0x00ff0000UL) >>  8) |		\
-	(((uint32_t)(x) & (uint32_t)0xff000000UL) >> 24) +		\
-		STATIC_ASSERT_EXPR(sizeof(x) == sizeof(uint32_t))))
+#define SWAB32(x) ((uint32_t)(( \
+	(ROTR(x, 8) & 0xFF00FF00) | \
+	(ROTL(x, 8) & 0x00FF00FF))) + \
+		STATIC_ASSERT_EXPR(sizeof(x) == sizeof(uint32_t)))
+#endif
 
+#if GNUC_PREREQ(4, 3)
+#define SWAB64(x) ((uint64_t)(__builtin_bswap64((x) + \
+		STATIC_ASSERT_EXPR(sizeof(x) == sizeof(uint64_t)))))
+#else
 /**
  * Reverse bytes in a 64-bit value.
  */
@@ -124,7 +132,7 @@ INLINE float swab_float(float x)
 	/* Avoid breaking strict aliasing rules.  */
 	char *cx = (char *)(&x);
 	STATIC_ASSERT(sizeof(float) == 4);
-	#define BYTEORDER_SWAP(a, b) ((a) ^= (b) ^= (a) ^= (b))
+	#define BYTEORDER_SWAP(a, b) do { (a) ^= (b); (b) ^= (a); (a) ^= (b); } while(0)
 	BYTEORDER_SWAP(cx[0], cx[3]);
 	BYTEORDER_SWAP(cx[1], cx[2]);
 	#undef BYTEORDER_SWAP
@@ -161,6 +169,37 @@ INLINE float net_to_host_float(float x)
 	return be_float_to_cpu(x);
 }
 
+#if CPU_ARM
+INLINE cpu_atomic_t
+cpu_atomic_xchg(volatile cpu_atomic_t *ptr, cpu_atomic_t val)
+{
+	cpu_atomic_t ret;
+
+	asm volatile(
+		"swp     %0, %1, [%2]"
+
+		: "=&r" (ret)
+		: "r" (val), "r" (ptr)
+		: "memory", "cc");
+
+	return ret;
+}
+#else /* CPU_ARM */
+#include <cpu/irq.h>
+
+INLINE cpu_atomic_t
+cpu_atomic_xchg(volatile cpu_atomic_t *ptr, cpu_atomic_t val)
+{
+	cpu_atomic_t ret;
+
+	ATOMIC(
+		ret = *ptr;
+		*ptr = val;
+	);
+	return ret;
+}
+#endif /* CPU_ARM */
+
 #ifdef __cplusplus
 
 /// Type generic byte swapping.