From 8677a23d5b053d550f70246de9c7dc8fd4e2fbf9 Mon Sep 17 00:00:00 2001 From: Stefan Reinauer Date: Sat, 11 Dec 2010 20:33:41 +0000 Subject: After this has been brought up many times before, rename src/arch/i386 to src/arch/x86. Signed-off-by: Stefan Reinauer Acked-by: Patrick Georgi git-svn-id: svn://svn.coreboot.org/coreboot/trunk@6161 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1 --- src/arch/x86/lib/walkcbfs.S | 126 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 126 insertions(+) create mode 100644 src/arch/x86/lib/walkcbfs.S (limited to 'src/arch/x86/lib/walkcbfs.S') diff --git a/src/arch/x86/lib/walkcbfs.S b/src/arch/x86/lib/walkcbfs.S new file mode 100644 index 0000000000..395c46e20c --- /dev/null +++ b/src/arch/x86/lib/walkcbfs.S @@ -0,0 +1,126 @@ +#define CBFS_HEADER_PTR 0xfffffffc + +#define CBFS_HEADER_MAGIC 0 +#define CBFS_HEADER_VERSION (CBFS_HEADER_MAGIC + 4) +#define CBFS_HEADER_ROMSIZE (CBFS_HEADER_VERSION + 4) +#define CBFS_HEADER_BOOTBLOCKSIZE (CBFS_HEADER_ROMSIZE + 4) +#define CBFS_HEADER_ALIGN (CBFS_HEADER_BOOTBLOCKSIZE + 4) +#define CBFS_HEADER_OFFSET (CBFS_HEADER_ALIGN + 4) + +#define CBFS_FILE_MAGIC 0 +#define CBFS_FILE_LEN (CBFS_FILE_MAGIC + 8) +#define CBFS_FILE_TYPE (CBFS_FILE_LEN + 4) +#define CBFS_FILE_CHECKSUM (CBFS_FILE_TYPE + 4) +#define CBFS_FILE_OFFSET (CBFS_FILE_CHECKSUM + 4) + +#define CBFS_FILE_STRUCTSIZE (CBFS_FILE_OFFSET + 4) + +#define CBFS_STAGE_COMPRESSION 0 +#define CBFS_STAGE_ENTRY (CBFS_STAGE_COMPRESSION + 4) +#define CBFS_STAGE_LOAD (CBFS_STAGE_ENTRY + 8) +#define CBFS_STAGE_LEN (CBFS_STAGE_LOAD + 8) +#define CBFS_STAGE_MEMLEN (CBFS_STAGE_LEN + 4) + +/* + input %esi: filename + input %esp: return address (not pointer to return address!) + output %eax: entry point + clobbers %ebx, %ecx, %edi +*/ +walkcbfs: + cld + + mov CBFS_HEADER_PTR, %eax + mov CBFS_HEADER_ROMSIZE(%eax), %ecx + bswap %ecx + mov $0, %ebx + sub %ecx, %ebx + mov CBFS_HEADER_OFFSET(%eax), %ecx + bswap %ecx + add %ecx, %ebx + + /* determine filename length */ + mov $0, %eax +1: + cmpb $0, (%eax,%esi) + jz 2f + add $1, %eax + jmp 1b +2: + add $1, %eax +walker: + mov 0(%ebx), %edi + cmp %edi, filemagic + jne searchfile + mov 4(%ebx), %edi + cmp %edi, filemagic+4 + jne searchfile + + mov %ebx, %edi + add $CBFS_FILE_STRUCTSIZE, %edi /* edi = address of first byte after struct cbfs_file */ + mov %eax, %ecx + repe cmpsb + # zero flag set if strings are equal + jnz tryharder + + # we found it! + mov CBFS_FILE_OFFSET(%ebx), %eax + bswap %eax + add %ebx, %eax + add $CBFS_STAGE_ENTRY, %eax /* eax = ((cbfs_stage* (cbfs_file* ebx)->offset)->entry) */ + mov 0(%eax), %eax + jmp *%esp + +tryharder: + sub %ebx, %edi + sub $CBFS_FILE_STRUCTSIZE, %edi /* edi = # of walked bytes */ + sub %edi, %esi /* esi = start of filename */ + + /* ebx = ecx = (current+offset+len+ALIGN-1) & ~(ALIGN-1) */ + mov CBFS_FILE_OFFSET(%ebx), %ecx + bswap %ecx + add %ebx, %ecx + mov CBFS_FILE_LEN(%ebx), %edi + bswap %edi + add %edi, %ecx + mov CBFS_HEADER_PTR, %edi + mov CBFS_HEADER_ALIGN(%edi), %edi + bswap %edi + sub $1, %edi + add %edi, %ecx + not %edi + and %edi, %ecx + + /* if oldaddr >= addr, leave */ + cmp %ebx, %ecx + jbe out + + mov %ecx, %ebx + +check_for_exit: + /* look if we should exit: did we pass into the bootblock already? */ + mov CBFS_HEADER_PTR, %ecx + mov CBFS_HEADER_BOOTBLOCKSIZE(%ecx), %ecx + bswap %ecx + not %ecx + add $1, %ecx + + cmp %ecx, %ebx + /* if bootblockstart >= addr (==we're still in the data area) , jump back */ + jbe walker + +out: + mov $0, %eax + jmp *%esp + + +searchfile: + /* if filemagic isn't found, move forward cbfs_header->align bytes */ + mov CBFS_HEADER_PTR, %edi + mov CBFS_HEADER_ALIGN(%edi), %edi + bswap %edi + add %edi, %ebx + jmp check_for_exit + +filemagic: + .ascii "LARCHIVE" -- cgit v1.2.3