diff options
Diffstat (limited to 'com32/modules/chain.c')
| -rw-r--r-- | com32/modules/chain.c | 25 |
1 files changed, 22 insertions, 3 deletions
diff --git a/com32/modules/chain.c b/com32/modules/chain.c index b93f38ed..89489d18 100644 --- a/com32/modules/chain.c +++ b/com32/modules/chain.c @@ -76,6 +76,10 @@ * equivalent to seg=0x70 file=<loader> sethidden, * used with DOS' io.sys. * + * drmk=<loader> + * Similar to msdos=<loader> but prepares the special options + * for the Dell Real Mode Kernel. + * * grub=<loader> * same as seg=0x800 file=<loader> & jumping to seg 0x820, * used with GRUB Legacy stage2 files. @@ -1707,16 +1711,31 @@ int main(int argc, char *argv[]) * We only really need 4 new, usable bytes at the end. */ int tsize = (data[ndata].size + 19) & 0xfffffff0; + const union syslinux_derivative_info *sdi; + + sdi = syslinux_derivative_info(); + /* We should lookup the Syslinux partition offset and use it */ + fs_lba = *sdi->disk.partoffset; + /* + * fs_lba should be verified against the disk as some DRMK + * variants will check and fail if it does not match + */ + dprintf(" fs_lba offset is %d\n", fs_lba); + /* DRMK only uses a DWORD */ + if (fs_lba > 0xffffffff) { + error("LBA very large; Only using lower 32 bits; DRMK will probably fail\n"); + } regs.ss = regs.fs = regs.gs = 0; /* Used before initialized */ if (!realloc(data[ndata].data, tsize)) { error("Failed to realloc for DRMK\n"); - goto bail; + goto bail; /* We'll never make it */ } data[ndata].size = tsize; - /* ds:[bp+28] must be 0x0000003f */ + /* ds:bp is assumed by DRMK to be the boot sector */ + /* offset 28 is the FAT HiddenSectors value */ regs.ds = (tsize >> 4) + (opt.seg - 2); /* "Patch" into tail of the new space */ - *(int *)(data[ndata].data + tsize - 4) = 0x0000003f; + *(int *)(data[ndata].data + tsize - 4) = (int)(fs_lba & 0xffffffff); } ndata++; |