Add support for Intel's XScale processor

1 files changed, 100 insertions, 0 deletions

diff --git a/newlib/libc/machine/xscale/strlen.c b/newlib/libc/machine/xscale/strlen.c
new file mode 100644
index 000000000..e113ade34
--- /dev/null
+++ b/newlib/libc/machine/xscale/strlen.c
@@ -0,0 +1,100 @@
+#if defined __thumb__ || defined(PREFER_SIZE_OVER_SPEED) || defined(__OPTIMIZE_SIZE__)
+
+#include "../../string/strlen.c"
+
+#else
+
+#include <string.h>
+#include "xscale.h"
+
+size_t
+strlen (const char *str)
+{
+  _CONST char *start = str;
+
+  /* Skip unaligned part.  */
+  if ((long)str & 3)
+    {
+      str--;
+      do
+	{
+	  if (*++str == '\0')
+	    goto out;
+	}
+      while ((long)str & 3);
+    }
+
+  /* Load two constants:
+     R4 = 0xfefefeff [ == ~(0x80808080 << 1) ]
+     R5 = 0x80808080  */
+
+  asm ("mov	r5, #0x80
+	add	r5, r5, #0x8000
+	add	r5, r5, r5, lsl #16
+	mvn	r4, r5, lsl #1
+"
+
+#if defined __ARM_ARCH_5__ || defined __ARM_ARCH_5T__ || defined __ARM_ARCH_5E__ || defined __ARM_ARCH_5TE__
+
+"	tst	%0, #0x7
+	ldreqd	r6, [%0]
+	beq	1f
+	ldr	r2, [%0]
+        add     r3, r2, r4
+        bic     r3, r3, r2
+        ands    r2, r3, r5
+	bne	2f
+	sub	%0, %0, #4
+
+0:
+	ldrd	r6, [%0, #8]!
+"
+	PRELOADSTR ("%0")
+"
+1:
+	add	r3, r6, r4
+	add	r2, r7, r4
+	bic	r3, r3, r6
+	bic	r2, r2, r7
+	and	r3, r3, r5
+	and	r2, r2, r5
+	orrs	r3, r2, r3
+	beq	0b
+"
+#else
+
+"	sub	%0, %0, #4
+
+0:
+	ldr	r6, [%0, #4]!
+"
+	PRELOADSTR ("%0")
+"
+	add	r3, r6, r4
+	bic	r3, r3, r6
+	ands	r3, r3, r5
+	beq	0b
+"
+#endif /* __ARM_ARCH_5[T][E]__ */
+"
+2:
+	ldrb	r3, [%0]
+	cmp	r3, #0x0
+	beq	1f
+
+0:
+	ldrb	r3, [%0, #1]!
+"
+	PRELOADSTR ("%0")
+"
+	cmp	r3, #0x0
+	bne	0b
+1:
+"
+       : "=r" (str) : "0" (str) : "r2", "r3", "r4", "r5", "r6", "r7");
+
+  out:
+  return str - start;
+}
+
+#endif