From: H. Peter Anvin <hpa@zytor.com>

Date: Mon, 19 Feb 2007 23:54:58 +0000 (-0800)

Subject: Comboot function READ DISK corrupts its arguments; fix.

X-Git-Tag: syslinux-3.40-pre10^0~13^2

X-Git-Url: http://www.jur-linux.org/git/?p=syslinux.git;a=commitdiff_plain;h=c7c51cdcd0a094c2588f8a816542bc57bb4efb34

Comboot function READ DISK corrupts its arguments; fix.

---

diff --git a/comboot.doc b/comboot.doc

index 8aaa0e7..0d70b48 100644

--- a/comboot.doc

+++ b/comboot.doc

@@ -723,7 +723,7 @@ AX=0018h [3.30]	Query custom font

 	been loaded, AL contains zero.

-AX=0019h [3.35] Read disk [SYSLINUX, ISOLINUX, EXTLINUX]

+AX=0019h [3.xx] Read disk [SYSLINUX, ISOLINUX, EXTLINUX]

 	Input:	AX	0019h

 		EDX	Sector number

 		ESI	Reserved - MUST BE ZERO

diff --git a/comboot.inc b/comboot.inc

index 0f544c2..5df900f 100644

--- a/comboot.inc

+++ b/comboot.inc

@@ -780,9 +780,9 @@ comapi_readdisk:

 		or esi,P_EDI		; are reserved for future expansion

 		jnz .err

 		mov eax,P_EDX

-		mov bp,P_CX

 		mov es,P_ES

 		mov bx,P_BX

+		mov bp,P_CX		; WE CANNOT use P_* after touching bp!

 		call getlinsec

 		clc

 		ret