[syslinux:master] comboot: allow the read disk API call to specify a 64-bit LBA
syslinux-bot for H. Peter Anvin
hpa at linux.intel.com
Mon Jun 21 15:18:17 PDT 2010
Commit-ID: 2f712545dd82f5906ec930b643d44e8b12295682
Gitweb: http://syslinux.zytor.com/commit/2f712545dd82f5906ec930b643d44e8b12295682
Author: H. Peter Anvin <hpa at linux.intel.com>
AuthorDate: Mon, 21 Jun 2010 15:12:48 -0700
Committer: H. Peter Anvin <hpa at linux.intel.com>
CommitDate: Mon, 21 Jun 2010 15:16:33 -0700
comboot: allow the read disk API call to specify a 64-bit LBA
We already had two MBZ fields reserved, so use one of them to expand
into a 64-bit LBA.
Signed-off-by: H. Peter Anvin <hpa at linux.intel.com>
---
core/comboot.inc | 4 ++--
doc/comboot.txt | 4 ++--
2 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/core/comboot.inc b/core/comboot.inc
index 0c9956a..91cc15a 100644
--- a/core/comboot.inc
+++ b/core/comboot.inc
@@ -837,10 +837,10 @@ comapi_userfont:
;
%if IS_SYSLINUX || IS_ISOLINUX || IS_EXTLINUX
comapi_readdisk:
- mov esi,P_ESI ; Enforce ESI == EDI == 0, these
- or esi,P_EDI ; are reserved for future expansion
+ cmp P_EDI,0 ; Reserved for future expansion
jnz .err
mov eax,P_EDX
+ mov edx,P_ESI
mov es,P_ES
mov bx,P_BX
mov bp,P_CX ; WE CANNOT use P_* after touching bp!
diff --git a/doc/comboot.txt b/doc/comboot.txt
index 036bd78..9e9f99a 100644
--- a/doc/comboot.txt
+++ b/doc/comboot.txt
@@ -832,8 +832,8 @@ AX=0018h [3.30] Query custom font
AX=0019h [3.50] Read disk [SYSLINUX, ISOLINUX, EXTLINUX]
Input: AX 0019h
- EDX Sector number
- ESI Reserved - MUST BE ZERO
+ EDX Sector number (LSW)
+ ESI Sector number (MSW) [4.00]
EDI Reserved - MUST BE ZERO
CX Sector count
ES:BX Buffer address
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