1 files changed, 124 insertions, 0 deletions
diff --git a/newlib/libc/machine/riscv/rv_string.h b/newlib/libc/machine/riscv/rv_string.h
new file mode 100644
index 0000000..362f66a
--- /dev/null
+++ b/newlib/libc/machine/riscv/rv_string.h
@@ -0,0 +1,124 @@
+/* Copyright (c) 2017  SiFive Inc. All rights reserved.
+
+   This copyrighted material is made available to anyone wishing to use,
+   modify, copy, or redistribute it subject to the terms and conditions
+   of the FreeBSD License.   This program is distributed in the hope that
+   it will be useful, but WITHOUT ANY WARRANTY expressed or implied,
+   including the implied warranties of MERCHANTABILITY or FITNESS FOR
+   A PARTICULAR PURPOSE.  A copy of this license is available at
+   http://www.opensource.org/licenses.
+*/
+
+#ifndef _RV_STRING_H
+#define _RV_STRING_H
+
+#include <stdbool.h>
+#include "xlenint.h"
+
+#if __riscv_zbb
+  #include <riscv_bitmanip.h>
+
+  // Determine which intrinsics to use based on XLEN and endianness
+  #if __riscv_xlen == 64
+    #define __LIBC_RISCV_ZBB_ORC_B(x)       __riscv_orc_b_64(x)
+
+    #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+      #define __LIBC_RISCV_ZBB_CNT_Z(x)     __riscv_ctz_64(x)
+    #else
+      #define __LIBC_RISCV_ZBB_CNT_Z(x)     __riscv_clz_64(x)
+    #endif
+  #else
+    #define __LIBC_RISCV_ZBB_ORC_B(x)       __riscv_orc_b_32(x)
+
+    #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+      #define __LIBC_RISCV_ZBB_CNT_Z(x)     __riscv_ctz_32(x)
+    #else
+      #define __LIBC_RISCV_ZBB_CNT_Z(x)     __riscv_clz_32(x)
+    #endif
+  #endif
+#endif
+
+
+static __inline uintxlen_t __libc_detect_null(uintxlen_t w)
+{
+#if __riscv_zbb
+  /*
+    If there are any zeros in each byte of the register, all bits will
+    be unset for that byte value, otherwise, all bits will be set.
+    If the value is -1, all bits are set, meaning no null byte was found.
+  */
+  return __LIBC_RISCV_ZBB_ORC_B(w) != -1;
+#else
+  uintxlen_t mask = 0x7f7f7f7f;
+  #if __riscv_xlen == 64
+    mask = ((mask << 16) << 16) | mask;
+  #endif
+  return ~(((w & mask) + mask) | w | mask);
+#endif
+}
+
+
+static __inline char *__libc_strcpy(char *dst, const char *src, bool ret_start)
+{
+  char *dst0 = dst;
+
+#if !defined(PREFER_SIZE_OVER_SPEED) && !defined(__OPTIMIZE_SIZE__)
+#if !(__riscv_misaligned_slow || __riscv_misaligned_fast)
+  int misaligned = ((uintxlen_t)dst | (uintxlen_t)src) & (sizeof (uintxlen_t) - 1);
+  if (__builtin_expect(!misaligned, 1))
+#endif
+    {
+      uintxlen_t *pdst = (uintxlen_t *)dst;
+      const uintxlen_t *psrc = (const uintxlen_t *)src;
+
+      while (!__libc_detect_null(*psrc))
+        *pdst++ = *psrc++;
+
+      dst = (char *)pdst;
+      src = (const char *)psrc;
+
+      if (ret_start)
+        {
+          if (!(*dst++ = src[0])) return dst0;
+          if (!(*dst++ = src[1])) return dst0;
+          if (!(*dst++ = src[2])) return dst0;
+          if (!(*dst++ = src[3])) return dst0;
+          #if __riscv_xlen == 64
+            if (!(*dst++ = src[4])) return dst0;
+            if (!(*dst++ = src[5])) return dst0;
+            if (!(*dst++ = src[6])) return dst0;
+          #endif
+        }
+      else
+        {
+          if (!(*dst++ = src[0])) return dst - 1;
+          if (!(*dst++ = src[1])) return dst - 1;
+          if (!(*dst++ = src[2])) return dst - 1;
+          if (!(*dst++ = src[3])) return dst - 1;
+          #if __riscv_xlen == 64
+            if (!(*dst++ = src[4])) return dst - 1;
+            if (!(*dst++ = src[5])) return dst - 1;
+            if (!(*dst++ = src[6])) return dst - 1;
+            dst0 = dst;
+          #endif
+        }
+
+      *dst = 0;
+      return dst0;
+    }
+#endif /* not PREFER_SIZE_OVER_SPEED */
+
+  char ch;
+  do
+    {
+      ch = *src;
+      src++;
+      dst++;
+      *(dst - 1) = ch;
+    } while (ch);
+
+  return ret_start ? dst0 : dst - 1;
+}
+
+
+#endif /* _RV_STRING_H */