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| author | H. Peter Anvin <hpa@zytor.com> | 2009-05-21 15:36:50 -0700 |
|---|---|---|
| committer | H. Peter Anvin <hpa@zytor.com> | 2009-05-21 15:36:50 -0700 |
| commit | e462c28ffaca0132c1761736bc93cb06a41dc7a6 (patch) | |
| tree | 24edb9f85175bdd6cc30bf270f3e59571bca71ae /core/isolinux.asm | |
| parent | d4d9f190900d31b5e9428401a0175012957d7cb7 (diff) | |
| download | syslinux-e462c28ffaca0132c1761736bc93cb06a41dc7a6.tar.gz | |
isohybrid: support booting from partition; fix CBIOS booting
Fix CBIOS in isohybrid mode. Also allow an isohybrid image to be
booted from a partition. Unfortunately this breaks compatibility
between differing versions of isohybrid and isolinux.bin.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Diffstat (limited to 'core/isolinux.asm')
| -rw-r--r-- | core/isolinux.asm | 29 |
1 files changed, 20 insertions, 9 deletions
diff --git a/core/isolinux.asm b/core/isolinux.asm index cc97f479..b85ecd36 100644 --- a/core/isolinux.asm +++ b/core/isolinux.asm @@ -112,6 +112,8 @@ DiskError resb 1 ; Error code for disk I/O DriveNumber resb 1 ; CD-ROM BIOS drive number ISOFlags resb 1 ; Flags for ISO directory search RetryCount resb 1 ; Used for disk access retries + alignb 8 +bsHidden resq 1 ; Used in hybrid mode bsSecPerTrack resw 1 ; Used in hybrid mode bsHeads resw 1 ; Used in hybrid mode @@ -222,26 +224,31 @@ bi_end: ; Custom entry point for the hybrid-mode disk. ; The following values will have been pushed onto the ; entry stack: - ; - CBIOS Heads - ; - CBIOS Sectors - ; - EBIOS flag - ; - DX (including drive number) - ; - DI ; - ES + ; - DI + ; - DX (including drive number) + ; - partition offset (qword) + ; - EBIOS flag + ; - CBIOS Sectors + ; - CBIOS Heads ; (top of stack) + ; %ifndef DEBUG_MESSAGES _hybrid_signature: - dd 0x7078c0fb ; An arbitrary number... - + dd 0x0defe3f7 _start_hybrid: + pop word [cs:bsHeads] + pop word [cs:bsSecPerTrack] + pop ax mov si,bios_cbios and ax,ax jz .cbios mov si,bios_ebios .cbios: - pop word [cs:bsSecPerTrack] - pop word [cs:bsHeads] + + pop dword [cs:bsHidden] + pop dword [cs:bsHidden+4] pop dx pop di @@ -745,6 +752,8 @@ getlinsec_ebios: xor edx,edx shld edx,eax,2 shl eax,2 ; Convert to HDD sectors + add eax,[bsHidden] + adc edx,[bsHidden+4] shl bp,2 .loop: @@ -814,7 +823,9 @@ getlinsec_ebios: ; getlinsec implementation for legacy CBIOS ; getlinsec_cbios: + xor edx,edx shl eax,2 ; Convert to HDD sectors + add eax,[bsHidden] shl bp,2 .loop: |