1 files changed, 93 insertions, 0 deletions
diff --git a/libc/sysdeps/linux/nds32/clone.S b/libc/sysdeps/linux/nds32/clone.S
new file mode 100644
index 000000000..5dba17896
--- /dev/null
+++ b/libc/sysdeps/linux/nds32/clone.S
@@ -0,0 +1,93 @@
+/*
+ * Copyright (C) 2016 Andes Technology, Inc.
+ * Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball.
+ */
+
+/* clone() is even more special than fork() as it mucks with stacks
+   and invokes a function in the right context after its all over.  */
+
+#include <sysdep.h>
+#include <sys/syscall.h>
+#define _ERRNO_H	1
+#include <bits/errno.h>
+
+/*
+       int clone(int (*fn)(void *), void *child_stack, int flags, void *arg);
+       _syscall2(int, clone, int, flags, void *, child_stack)
+*/
+
+ENTRY(__clone)
+#ifdef PIC
+	/* set GP register to parent only, cause child's $SP will be $r1. */
+	pushm	$fp, $gp
+#ifndef __NDS32_N1213_43U1H__
+	mfusr $r15, $PC
+#endif
+	sethi	$gp,	hi20(_GLOBAL_OFFSET_TABLE_+4)
+	ori	$gp,	$gp,	lo12(_GLOBAL_OFFSET_TABLE_+8)
+	add	$gp,	$gp,	$r15
+#endif
+        /* sanity check arguments.  */
+        beqz    $r0, 1f
+        bnez    $r1, 2f
+
+1:
+        movi    $r0, -EINVAL
+5:
+#ifdef PIC
+		  /* restore GP register, only in parent's stack */
+		  popm	$fp, $gp
+        la      $r15, C_SYMBOL_NAME(__syscall_error@PLT)
+        jr      $r15
+#else
+        b       C_SYMBOL_NAME(__syscall_error)
+#endif
+
+2:
+	/* Child's $SP will be $r1, push to child's stack only. */
+	addi	$r1, $r1, -4
+        swi.p   $r3, [$r1], -4  ! arg
+        swi     $r0, [$r1]  ! fn
+
+        /* do the system call */
+        or      $r0, $r2, $r2   ! move r0, r2
+        __do_syscall(clone)
+	!syscall (__NR_clone)
+        beqz    $r0, 4f
+        bltz    $r0, 5b
+
+        ! parent
+#ifdef PIC
+	/* restore GP register, only in parent's stack */
+	popm	$fp, $gp
+#endif
+        ret
+
+4:
+	/* Only in child's stack. */
+        pop     $r1  ! fn
+        pop     $r0  ! arg
+#if defined(NDS32_ABI_2) || defined(NDS32_ABI_2FP)
+#else
+	addi	$sp, $sp, -24
+#endif
+	! use r15 in case _exit is PIC
+#ifdef __NDS32_N1213_43U1H__
+        or      $r15, $r1, $r1   ! move r15, r2
+#endif
+        bral    $r1
+#if defined(NDS32_ABI_2) || defined(NDS32_ABI_2FP)
+#else
+	addi	$sp, $sp, 24
+#endif
+	! use r15 in case _exit is PIC
+#ifdef PIC
+        la      $r15, C_SYMBOL_NAME(_exit@PLT)
+        jr      $r15
+#else
+        b       C_SYMBOL_NAME(_exit)
+#endif
+
+
+PSEUDO_END (__clone)
+weak_alias (__clone, clone)