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| author | H. Peter Anvin <hpa@zytor.com> | 2008-02-21 19:32:59 -0800 |
|---|---|---|
| committer | H. Peter Anvin <hpa@zytor.com> | 2008-02-21 19:32:59 -0800 |
| commit | 7c028ed3b4fb62d42fad88c36ea86d904ceee86d (patch) | |
| tree | a8a9cf7d0883c389b30f93b61a358146f623724e /doc | |
| parent | b73533206d9f5a4e718fdfaace6370ddd7f3628e (diff) | |
| download | syslinux-elf-7c028ed3b4fb62d42fad88c36ea86d904ceee86d.tar.gz syslinux-elf-7c028ed3b4fb62d42fad88c36ea86d904ceee86d.tar.xz syslinux-elf-7c028ed3b4fb62d42fad88c36ea86d904ceee86d.zip | |
Document intent at no longer providing file length a priori
We intend to no longer guarantee that we know the file size ahead of
time.
Diffstat (limited to 'doc')
| -rw-r--r-- | doc/comboot.doc | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/doc/comboot.doc b/doc/comboot.doc index 46afc64c..c4e303af 100644 --- a/doc/comboot.doc +++ b/doc/comboot.doc @@ -293,7 +293,7 @@ AX=0006h [2.08] Open file Input: AX 0006h ES:SI null-terminated filename Output: SI file handle - EAX length of file in bytes + EAX length of file in bytes, or -1 CX file block size Open a file for reading. The exact syntax of the filenames @@ -304,6 +304,9 @@ AX=0006h [2.08] Open file Note: SYSLINUX considers a zero-length file to be nonexistent. + In 3.70 or later, EAX can contain -1 indicating that the file + length is unknown. + AX=0007h [2.08] Read file @@ -312,6 +315,7 @@ AX=0007h [2.08] Read file ES:BX buffer CX number of blocks to read Output: SI file handle, or 0 if EOF was reached + EAX number of bytes read [3.70] Read blocks from a file. Note that the file handle that is returned in SI may not be the same value that was passed in. @@ -319,6 +323,10 @@ AX=0007h [2.08] Read file If end of file was reached (SI=0), the file was automatically closed. + In 3.70 or later, EAX returns the number of bytes read. This + will always be a multiple of the block size unless EOF is + reached. + The address of the buffer (ES:BX) should be at least 512-byte aligned. SYSLINUX guarantees at least this alignment for the COMBOOT load segment or the COM32 bounce buffer. |