String-handling functions for the new x86 setup code.

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>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 153 insertions, 0 deletions

diff --git a/arch/i386/boot/copy.S b/arch/i386/boot/copy.S
new file mode 100644
index 000000000000..ef127e56a3cf
--- /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 000000000000..481a22097781
--- /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;
+}