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-rw-r--r--contrib/syslinux-4.02/memdisk/memcpy.S86
1 files changed, 86 insertions, 0 deletions
diff --git a/contrib/syslinux-4.02/memdisk/memcpy.S b/contrib/syslinux-4.02/memdisk/memcpy.S
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+/* ----------------------------------------------------------------------- *
+ *
+ * Copyright 2008 H. Peter Anvin - All Rights Reserved
+ *
+ * Permission is hereby granted, free of charge, to any person
+ * obtaining a copy of this software and associated documentation
+ * files (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom
+ * the Software is furnished to do so, subject to the following
+ * conditions:
+ *
+ * The above copyright notice and this permission notice shall
+ * be included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+ * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+ * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * memcpy.S
+ *
+ * Reasonably efficient memcpy, using aligned transfers at least
+ * for the destination operand.
+ */
+
+ .text
+ .globl memcpy
+ .type memcpy, @function
+memcpy:
+ jecxz 1f
+
+ pushl %esi
+ pushl %edi
+ pushl %eax /* Return value */
+
+ movl %eax,%edi
+ movl %edx,%esi
+
+ /* Initial alignment */
+ movl %edi,%edx
+ shrl $1,%edx
+ jnc 11f
+ movsb
+ decl %ecx
+11:
+ movb %cl,%al
+ cmpl $2,%ecx
+ jb 13f
+
+ shrl $1,%edx
+ jnc 12f
+ movsw
+ subl $2,%ecx
+12:
+ /* Bulk transfer */
+ movb %cl,%al
+ shrl $2,%ecx
+ rep; movsl
+
+ /* Final alignment */
+ testb $2,%al
+ jz 14f
+ movsw
+13:
+14:
+ testb $1,%al
+ jz 15f
+ movsb
+15:
+
+ popl %eax /* Return value */
+ popl %edi
+ popl %esi
+1:
+ ret
+
+ .size memcpy, .-memcpy