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authorH. Peter Anvin <hpa@zytor.com>2009-06-07 18:47:35 -0700
committerH. Peter Anvin <hpa@zytor.com>2009-06-07 18:47:35 -0700
commit1e4de8c54d7e007cf6002a87658f3d03c796bfc6 (patch)
treed8cc19b215fd983c05ad0b96d5da2365c9cf07de /memdisk
parentc88854e0d66289c6135bd7d68dc5cab95b6e1092 (diff)
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memdisk: add missing memmove.S
We need memmove.S in the memdisk directory... Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Diffstat (limited to 'memdisk')
-rw-r--r--memdisk/memmove.S139
1 files changed, 139 insertions, 0 deletions
diff --git a/memdisk/memmove.S b/memdisk/memmove.S
new file mode 100644
index 00000000..b7ac6767
--- /dev/null
+++ b/memdisk/memmove.S
@@ -0,0 +1,139 @@
+/* ----------------------------------------------------------------------- *
+ *
+ * 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.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * memmove.S
+ *
+ * Reasonably efficient memmove, using aligned transfers at least
+ * for the destination operand.
+ */
+
+ .globl memmove
+ .type memmove,@function
+ .text
+memmove:
+ jecxz 3f
+
+ pushl %esi
+ pushl %edi
+ pushl %eax /* Return value */
+
+ movl %eax,%edi
+ movl %edx,%esi
+
+ cmpl %edi,%esi
+ jb 1f
+
+ /* source >= dest, forwards move */
+
+ /* 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:
+ jmp 2f
+
+
+1:
+ /* source < dest, backwards move */
+ std
+ leal -1(%ecx,%esi),%esi
+ leal -1(%ecx,%edi),%edi
+
+ /* Initial alignment */
+ movl %edi,%edx
+ shrl $1,%edx
+ jc 21f
+ movsb
+ decl %ecx
+21:
+ decl %esi
+ decl %edi
+ movb %cl,%al
+ cmpl $2,%ecx
+ jb 23f
+ shrl $1,%edx
+ jc 22f
+ movsw
+ subl $2,%ecx
+22:
+ /* Bulk transfer */
+ subl $2,%esi
+ subl $2,%edi
+ movb %cl,%al
+ shrl $2,%ecx
+ rep; movsl
+
+ /* Final alignment */
+ addl $2,%esi
+ addl $2,%edi
+ testb $2,%al
+ jz 24f
+ movsw
+23:
+24:
+ incl %esi
+ incl %edi
+ testb $1,%al
+ jz 25f
+ movsb
+25:
+ cld
+2:
+ popl %eax /* Return value */
+ popl %edi
+ popl %esi
+3:
+ ret
+
+ .size memmove, .-memmove