Aligning memcpy/memmove/mempcpy/memset for libcom32

Aligning versions of memcpy/memmove/mempcpy/memset for libcom32.

5 files changed, 308 insertions, 80 deletions

diff --git a/com32/lib/memcpy.S b/com32/lib/memcpy.S
index a893d247..5f2c4ec7 100644
--- a/com32/lib/memcpy.S
+++ b/com32/lib/memcpy.S
@@ -1,35 +1,86 @@
-#
-# memcpy.S
-#
+/* ----------------------------------------------------------------------- *
+ *
+ *   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
-#ifdef REGPARM
-	movl	%edx, %esi
-#else
-	movl	12(%esp), %eax
-	movl	16(%esp), %esi
-	movl	20(%esp), %ecx
-#endif
-	movl	%eax, %edi
-	movl	%ecx, %edx
-
-	shrl	$2, %ecx
-	rep ; movsl
-
-	jnc	1f		# The shrl had carry out if odd word count
+	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
-1:
-	testb	$1, %dl
-	jz	2f
+13:
+14:
+	testb	$1,%al
+	jz	15f
 	movsb
-2:
+15:
+
+	popl	%eax		/* Return value */
 	popl	%edi
 	popl	%esi
+1:	
 	ret
 
 	.size	memcpy, .-memcpy
diff --git a/com32/lib/memmove.S b/com32/lib/memmove.S
index e39f884b..90bbf3be 100644
--- a/com32/lib/memmove.S
+++ b/com32/lib/memmove.S
@@ -1,6 +1,6 @@
 /* ----------------------------------------------------------------------- *
  *
- *   Copyright 2008 rPath, Inc. - All Rights Reserved
+ *   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
@@ -28,16 +28,20 @@
 /*
  * memmove.S
  *
- * Reasonably efficient memmove
+ * 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
 
@@ -45,35 +49,91 @@ memmove:
 	jb	1f
 
 	/* source >= dest, forwards move */
-	movl	%ecx,%edx
-	shrl	$2,%ecx
-	andl	$3,%edx
 
+	/* 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
-	movl	%edx,%ecx
-	rep; movsb
 
+	/* Final alignment */
+	testb	$2,%al
+	jz	14f
+	movsw
+13:
+14:
+	testb	$1,%al
+	jz	15f
+	movsb
+15:
 	jmp	2f
+
+
 1:
 	/* source < dest, backwards move */
-	leal	-4(%ecx,%esi),%esi
-	leal	-4(%ecx,%edi),%edi
+	std
+	leal	-1(%ecx,%esi),%esi
+	leal	-1(%ecx,%edi),%edi
 
-	movl	%ecx,%edx
+	/* Initial alignment */
+	movl	%edi,%edx
+	shrl	$1,%edx
+	jnc	21f
+	movsb
+	decl	%ecx
+21:
+	decl	%esi
+	decl	%edi
+	movb	%cl,%al
+	cmpl	$2,%ecx
+	jb	23f
+	shrl	$1,%edx
+	jnc	22f
+	movsw
+	subl	$2,%ecx
+22:
+	/* Bulk transfer */
+	subl	$2,%esi
+	subl	$2,%edi
+	movb	%cl,%al
 	shrl	$2,%ecx
-	andl	$3,%edx
-
-	std
 	rep; movsl
-	movl	%edx,%ecx
-	addl	$3,%esi
-	addl	$3,%edi
-	rep; movsb
-	cld
 
+	/* 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
diff --git a/com32/lib/mempcpy.S b/com32/lib/mempcpy.S
index eeab9187..f6961f66 100644
--- a/com32/lib/mempcpy.S
+++ b/com32/lib/mempcpy.S
@@ -1,36 +1,85 @@
-#
-# mempcpy.S
-#
+/* ----------------------------------------------------------------------- *
+ *
+ *   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.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * mempcpy.S
+ *
+ * Reasonably efficient mempcpy, using aligned transfers at least
+ * for the destination operand.
+ */
 
 	.text
 	.globl	mempcpy
 	.type	mempcpy, @function
 mempcpy:
+	jecxz	1f
+
 	pushl	%esi
 	pushl	%edi
-#ifdef REGPARM
-	movl	%edx, %esi
-#else
-	movl	12(%esp), %eax
-	movl	16(%esp), %esi
-	movl	20(%esp), %ecx
-#endif
-	movl	%eax, %edi
-	movl	%ecx, %edx
-
-	shrl	$2, %ecx
-	rep ; movsl
-
-	jnc	1f		# The shrl had carry out if odd word count
+
+	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
-1:
-	testb	$1, %dl
-	jz	2f
+13:
+14:
+	testb	$1,%al
+	jz	15f
 	movsb
-2:
-	movl	%edi, %eax
+15:
+
+	movl	%edi,%eax	/* Return value */
 	popl	%edi
 	popl	%esi
+1:	
 	ret
 
 	.size	mempcpy, .-mempcpy
diff --git a/com32/lib/memset.S b/com32/lib/memset.S
new file mode 100644
index 00000000..4b2583c3
--- /dev/null
+++ b/com32/lib/memset.S
@@ -0,0 +1,86 @@
+/* ----------------------------------------------------------------------- *
+ *
+ *   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.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * memset.S
+ *
+ * Reasonably efficient memset, using aligned transfers at least
+ * for the destination operand.
+ */
+
+	.globl	memset
+	.type	memset,@function
+	.text
+memset:
+	jecxz	6f
+
+	pushl	%edi
+	pushl	%ebx
+	pushl	%eax		/* Return value */
+
+	movl	%eax,%edi
+	movb	%dl,%dh
+	movzwl	%dx,%eax
+	shll	$16,%edx
+	orl	%edx,%eax
+	
+	/* Initial alignment */
+	movl	%edi,%edx
+	shrl	$1,%edx
+	jnc	1f
+	stosb
+	decl	%ecx
+1:
+	movb	%cl,%bl
+	cmpl	$2,%ecx
+	jb	3f
+	shrl	$1,%edx
+	jnc	2f
+	stosw
+	subl	$2,%ecx
+2:
+	/* Bulk transfer */
+	movb	%cl,%bl
+	shrl	$2,%ecx
+	rep; stosl
+
+	testb	$2,%bl
+	jz	4f
+	stosw
+3:
+4:
+	testb	$1,%bl
+	jz	5f
+	stosb
+5:
+	popl	%eax		/* Return value */
+	popl	%ebx
+	popl	%edi
+6:
+	ret
+
+	.size	memset, .-memset
diff --git a/com32/lib/memset.c b/com32/lib/memset.c
deleted file mode 100644
index 516ad475..00000000
--- a/com32/lib/memset.c
+++ /dev/null
@@ -1,18 +0,0 @@
-/*
- * memset.c
- */
-
-#include <string.h>
-#include <stdint.h>
-
-void *memset(void *dst, int c, size_t n)
-{
-  char *q = dst;
-  size_t nl = n >> 2;
-
-  asm volatile("rep ; stosl ; movl %3,%0 ; rep ; stosb"
-	       : "+c" (nl), "+D" (q)
-	       : "a" ((unsigned char)c * 0x01010101U), "r" (n & 3));
-
-  return dst;
-}