diff options
Diffstat (limited to 'src/arch/i386/lib/walkcbfs.S')
| -rw-r--r-- | src/arch/i386/lib/walkcbfs.S | 42 |
1 files changed, 23 insertions, 19 deletions
diff --git a/src/arch/i386/lib/walkcbfs.S b/src/arch/i386/lib/walkcbfs.S index aba0453d1f..d043af5690 100644 --- a/src/arch/i386/lib/walkcbfs.S +++ b/src/arch/i386/lib/walkcbfs.S @@ -25,18 +25,9 @@ input %esi: filename input %esp: return address (not pointer to return address!) output %eax: entry point - clobbers %ebx, %ecx, %edx, %edi, %ebp + clobbers %ebx, %ecx, %edi */ walkcbfs: - mov %esi, %ebp /* stash away filename pointer */ - mov $0, %edx -1: - cmpb $0, (%edx,%esi) - jz 2f - add $1, %edx - jmp 1b -2: - add $1, %edx mov CBFS_HEADER_PTR, %eax mov CBFS_HEADER_ROMSIZE(%eax), %ecx bswap %ecx @@ -45,15 +36,20 @@ walkcbfs: mov CBFS_HEADER_OFFSET(%eax), %ecx bswap %ecx add %ecx, %ebx - mov CBFS_HEADER_ALIGN(%eax), %eax - bswap %eax - sub $1, %eax + /* determine filename length */ + mov $0, %eax +1: + cmpb $0, (%eax,%esi) + jz 2f + add $1, %eax + jmp 1b +2: + add $1, %eax walker: - mov %ebp, %esi mov %ebx, %edi add $CBFS_FILE_STRUCTSIZE, %edi /* edi = address of first byte after struct cbfs_file */ - mov %edx, %ecx + mov %eax, %ecx repe cmpsb # zero flag set if strings are equal jnz tryharder @@ -67,21 +63,29 @@ walker: jmp *%esp tryharder: + sub %ebx, %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 - add %eax, %ecx - mov %eax, %edi + mov CBFS_HEADER_PTR, %ebx + mov CBFS_HEADER_ALIGN(%ebx), %ebx + bswap %ebx + sub $1, %ebx + add %ebx, %ecx + mov %ebx, %edi not %edi and %edi, %ecx mov %ecx, %ebx /* look if we should exit */ - mov CBFS_HEADER_PTR, %esi - mov CBFS_HEADER_ROMSIZE(%esi), %ecx + mov CBFS_HEADER_PTR, %ecx + mov CBFS_HEADER_ROMSIZE(%ecx), %ecx bswap %ecx not %ecx add $1, %ecx |