[coreboot] [commit] r6498 - trunk/src/arch/x86/lib

[repository service]

Author: stepan
Date: Thu Apr 14 22:33:53 2011
New Revision: 6498
URL: https://tracker.coreboot.org/trac/coreboot/changeset/6498

Log:
add some comments to walkcbfs.S

Signed-off-by: Stefan Reinauer 
Acked-by: Stefan Reinauer

Modified:
   trunk/src/arch/x86/lib/walkcbfs.S

Modified: trunk/src/arch/x86/lib/walkcbfs.S
==============================================================================
--- trunk/src/arch/x86/lib/walkcbfs.S	Thu Apr 14 22:30:21 2011	(r6497)
+++ trunk/src/arch/x86/lib/walkcbfs.S	Thu Apr 14 22:33:53 2011	(r6498)
@@ -16,11 +16,11 @@
 #define CBFS_FILE_STRUCTSIZE (CBFS_FILE_OFFSET + 4)

/*
-  input %esi: filename
-  input %esp: return address (not pointer to return address!)
-  output %eax: entry point
-  clobbers %ebx, %ecx, %edi
-*/
+ * input %esi: filename
+ * input %esp: return address (not pointer to return address!)
+ * output %eax: entry point
+ * clobbers %ebx, %ecx, %edi
+ */
 walkcbfs_asm:
    cld

@@ -28,10 +28,10 @@
    mov CBFS_HEADER_ROMSIZE(%eax), %ecx
    bswap %ecx
    mov $0, %ebx
-	sub %ecx, %ebx
+	sub %ecx, %ebx	/* rom base address in ebx */
    mov CBFS_HEADER_OFFSET(%eax), %ecx
    bswap %ecx
-	add %ecx, %ebx
+	add %ecx, %ebx	/* address where we start looking for LARCHIVEs */

/* determine filename length */
    mov $0, %eax
@@ -43,21 +43,22 @@
 2:
    add $1, %eax
 walker:
-	mov 0(%ebx), %edi
+	mov 0(%ebx), %edi /* Check for LARCHIVE header */
    cmp %edi, filemagic
    jne searchfile
    mov 4(%ebx), %edi
    cmp %edi, filemagic+4
    jne searchfile

+	/* LARCHIVE header found */
    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
+	/* zero flag set if strings are equal */
    jnz tryharder

-	# we found it!
+	/* we found it! */
    mov CBFS_FILE_OFFSET(%ebx), %eax
    bswap %eax
    add %ebx, %eax