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Subject[x86 setup 16/33] String-handling functions for the new x86 setup code.
Date
From: H. Peter Anvin <hpa@zytor.com>

strcmp(), memcpy(), memset(), as well as routines to copy to and from
other segments (as pointed to by fs and gs).

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
---
arch/i386/boot/copy.S | 101 +++++++++++++++++++++++++++++++++++++++++++++++
arch/i386/boot/string.c | 52 ++++++++++++++++++++++++
2 files changed, 153 insertions(+), 0 deletions(-)
create mode 100644 arch/i386/boot/copy.S
create mode 100644 arch/i386/boot/string.c
diff --git a/arch/i386/boot/copy.S b/arch/i386/boot/copy.S
new file mode 100644
index 0000000..ef127e5
--- /dev/null
+++ b/arch/i386/boot/copy.S
@@ -0,0 +1,101 @@
+/* ----------------------------------------------------------------------- *
+ *
+ * Copyright (C) 1991, 1992 Linus Torvalds
+ * Copyright 2007 rPath, Inc. - All Rights Reserved
+ *
+ * This file is part of the Linux kernel, and is made available under
+ * the terms of the GNU General Public License version 2.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * arch/i386/boot/copy.S
+ *
+ * Memory copy routines
+ */
+
+ .code16gcc
+ .text
+
+ .globl memcpy
+ .type memcpy, @function
+memcpy:
+ pushw %si
+ pushw %di
+ movw %ax, %di
+ movw %dx, %si
+ pushw %cx
+ shrw $2, %cx
+ rep; movsl
+ popw %cx
+ andw $3, %cx
+ rep; movsb
+ popw %di
+ popw %si
+ ret
+ .size memcpy, .-memcpy
+
+ .globl memset
+ .type memset, @function
+memset:
+ pushw %di
+ movw %ax, %di
+ movzbl %dl, %eax
+ imull $0x01010101,%eax
+ pushw %cx
+ shrw $2, %cx
+ rep; stosl
+ popw %cx
+ andw $3, %cx
+ rep; stosb
+ popw %di
+ ret
+ .size memset, .-memset
+
+ .globl copy_from_fs
+ .type copy_from_fs, @function
+copy_from_fs:
+ pushw %ds
+ pushw %fs
+ popw %ds
+ call memcpy
+ popw %ds
+ ret
+ .size copy_from_fs, .-copy_from_fs
+
+ .globl copy_to_fs
+ .type copy_to_fs, @function
+copy_to_fs:
+ pushw %es
+ pushw %fs
+ popw %es
+ call memcpy
+ popw %es
+ ret
+ .size copy_to_fs, .-copy_to_fs
+
+#if 0 /* Not currently used, but can be enabled as needed */
+
+ .globl copy_from_gs
+ .type copy_from_gs, @function
+copy_from_gs:
+ pushw %ds
+ pushw %gs
+ popw %ds
+ call memcpy
+ popw %ds
+ ret
+ .size copy_from_gs, .-copy_from_gs
+ .globl copy_to_gs
+
+ .type copy_to_gs, @function
+copy_to_gs:
+ pushw %es
+ pushw %gs
+ popw %es
+ call memcpy
+ popw %es
+ ret
+ .size copy_to_gs, .-copy_to_gs
+
+#endif
diff --git a/arch/i386/boot/string.c b/arch/i386/boot/string.c
new file mode 100644
index 0000000..481a220
--- /dev/null
+++ b/arch/i386/boot/string.c
@@ -0,0 +1,52 @@
+/* -*- linux-c -*- ------------------------------------------------------- *
+ *
+ * Copyright (C) 1991, 1992 Linus Torvalds
+ * Copyright 2007 rPath, Inc. - All Rights Reserved
+ *
+ * This file is part of the Linux kernel, and is made available under
+ * the terms of the GNU General Public License version 2.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * arch/i386/boot/string.c
+ *
+ * Very basic string functions
+ */
+
+#include "boot.h"
+
+int strcmp(const char *str1, const char *str2)
+{
+ const unsigned char *s1 = (const unsigned char *)str1;
+ const unsigned char *s2 = (const unsigned char *)str2;
+ int delta = 0;
+
+ while (*s1 || *s2) {
+ delta = *s2 - *s1;
+ if (delta)
+ return delta;
+ s1++;
+ s2++;
+ }
+ return 0;
+}
+
+size_t strnlen(const char *s, size_t maxlen)
+{
+ const char *es = s;
+ while (*es && maxlen) {
+ es++;
+ maxlen--;
+ }
+
+ return (es - s);
+}
+
+unsigned int atou(const char *s)
+{
+ unsigned int i = 0;
+ while (isdigit(*s))
+ i = i * 10 + (*s++ - '0');
+ return i;
+}
--
1.5.2.2
-
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