Add support for Intel's XScale processor

1 files changed, 107 insertions, 0 deletions

diff --git a/newlib/libc/machine/xscale/strcmp.c b/newlib/libc/machine/xscale/strcmp.c
new file mode 100644
index 000000000..d9ec99b5d
--- /dev/null
+++ b/newlib/libc/machine/xscale/strcmp.c
@@ -0,0 +1,107 @@
+#if defined __thumb__
+
+#include "../../string/strcmp.c"
+
+#else
+
+#include <string.h>
+#include "xscale.h"
+
+int
+strcmp (const char *s1, const char *s2)
+{
+  asm (PRELOADSTR ("%0") : : "r" (s1));
+  asm (PRELOADSTR ("%0") : : "r" (s2));
+
+#ifndef __OPTIMIZE_SIZE__
+  if (((long)s1 & 3) == ((long)s2 & 3))
+    {
+      int result;
+
+      /* Skip unaligned part.  */
+      while ((long)s1 & 3)
+	{
+	  if (*s1 == '\0' || *s1 != *s2)
+	    goto out;
+	  s1++;
+	  s2++;
+	}
+
+  /* Load two constants:
+     lr = 0xfefefeff [ == ~(0x80808080 << 1) ]
+     ip = 0x80808080  */
+
+      asm (
+       "ldr	r2, [%1, #0]
+	ldr	r3, [%2, #0]
+	cmp	r2, r3
+	bne	2f
+
+	mov	ip, #0x80
+	add	ip, ip, #0x8000
+	add	ip, ip, ip, lsl #16
+	mvn	lr, ip, lsl #1
+
+0:
+	ldr	r2, [%1, #0]
+	add	r3, r2, lr
+	bic	r3, r3, r2
+	tst	r3, ip
+	beq	1f
+	mov	%0, #0x0
+	b	3f
+1:
+	ldr	r2, [%1, #4]!
+	ldr	r3, [%2, #4]!
+"	PRELOADSTR("%1") "
+"	PRELOADSTR("%2") "
+	cmp	r2, r3
+	beq	0b"
+
+       /* The following part could be done in a C loop as well, but it needs
+	  to be assembler to save some cycles in the case where the optimized
+	  loop above finds the strings to be equal.  */
+"
+2:
+	ldrb	r2, [%1, #0]
+"	PRELOADSTR("%1") "
+"	PRELOADSTR("%2") "
+	cmp	r2, #0x0
+	beq	1f
+	ldrb	r3, [%2, #0]
+	cmp	r2, r3
+	bne	1f
+0:
+	ldrb	r3, [%1, #1]!
+	add	%2, %2, #1
+	ands	ip, r3, #0xff
+	beq	1f
+	ldrb	r3, [%2]
+	cmp	ip, r3
+	beq	0b
+1:
+	ldrb	lr, [%1, #0]
+	ldrb	ip, [%2, #0]
+	rsb	%0, ip, lr
+3:
+"
+
+       : "=r" (result), "=&r" (s1), "=&r" (s2)
+       : "1" (s1), "2" (s2)
+       : "lr", "ip", "r2", "r3", "cc");
+      return result;
+    }
+#endif
+
+  while (*s1 != '\0' && *s1 == *s2)
+    {
+      asm (PRELOADSTR("%0") : : "r" (s1));
+      asm (PRELOADSTR("%0") : : "r" (s2));
+      s1++;
+      s2++;
+    }
+ out:
+  return (*(unsigned char *) s1) - (*(unsigned char *) s2);
+}
+
+#endif