diff options
Diffstat (limited to 'bootblocks/bootlist.s')
| -rw-r--r-- | bootblocks/bootlist.s | 257 |
1 files changed, 0 insertions, 257 deletions
diff --git a/bootblocks/bootlist.s b/bootblocks/bootlist.s deleted file mode 100644 index a9c603c..0000000 --- a/bootblocks/bootlist.s +++ /dev/null @@ -1,257 +0,0 @@ -! This bootsector is modified by the installer to have a list of sectors at -! offset 256. - -! Table format is a list of dwords. Each dword has a partition offest in -! the low 24 bits and a count in the high. -! -! Prob better to make it: HH DD MM LL rather than DD HH MM LL -! as this matches the BIOS better -! -! Note: -! Stack top is at abs location 64k. -! - -! PS: This hasn't been tested much ... make that at all! - -BOOTSEG = 0x07c0 -LOADSEG = 0x07e0 ! Just after boot sector. - -public linear -linear = 1 ! Is linear processing done ? (0 doesn't work) -public floppy -floppy = 0 *linear ! Allow for floppy drive ? (don't work) -public reloc -reloc = 1 *linear ! Auto configure of bootpart. - -macro locn - if *-start>?1 - fail! ?1 - endif - .blkb ?1 + start-* -mend - -use16 -entry start - -org $7b00 - -! temporary space - -n_cyl: .blkw 1 -n_secs: .blkw 1 -t_drive: .blkb 1 -t_sector: .blkb 1 -t_secs: .blkw 1 - -org $7c00 -start: - j code - -runit: - jmpi 0,0 ! This instruction is altered by the installer - -public execaddr ! Via this label. -execaddr = *-4 - -public bootpart -bootpart: - .data4 0x80000011 -code: - - if reloc - mov cx,[si+8] ! Fetch the linear address of part from DS:SI - mov dh,[si+10] ! DL is drive number - xchg dl,dh ! Into normal form. - endif - - xor ax,ax - mov ds,ax - mov ss,ax - mov sp,ax - - if reloc - mov [bootpart],cx - mov [bootpart+2],dx - endif - -! ASSUME ds=ss= 0 (cs should also be zero) - - mov ax,#LOADSEG - mov es,ax - - mov si,#table -load_addrs: - cld - - if linear - lodsw - mov cx,ax - add cx,[bootpart] - lodsw - mov dx,[bootpart+2] - adc dl,al - mov al,ah - else - lodsw ; XXX Broken, doesn't set AL correctly. - mov cx,ax - lodsw - mov dx,ax - lodsb - endif - - test al,al - jz runit - -loadem: - xor bx,bx - push ax - call cread - jc failed - pop ax - mov cl,#5 - sal ax,cl - mov bx,es - add ax,bx - mov es,ax - j load_addrs - -! Humm, something goes wrong, not much we can do ... -! Let`s squeak then try again -failed: - mov ax,#$0E45 - mov bx,#7 - int $10 - pop ax - - j loadem - -cread: - ! This function is like BIOS 1302 but it`s linear. - ! It's taken, almost, intact from LILO. - - ! DH is drive, DL:CX is linear address, AL is count. - ! ES:BX is load address, beware of DMA limitations - - ! All registers except AX and flags are preserved. - - mov t_secs,al ! save number of sectors -lnread: push cx ! keep linear address - push dx - xchg dl,dh - - if linear - if floppy - test dl,#0x80 ! Floppy is physical only. - jz lrd - endif - - push bx ! BX is used as scratch - push cx ! LSW - push dx ! MSW with drive - mov ah,#8 ! get drive geometry (do not clobber ES:DI) - push es - push di - int 0x13 - pop di - pop es - mov bl,dh ! BL <- #heads - pop dx ! get MSW - - jnc int_ok ! error -> quit - - pop cx ! discard stack contents - pop bx - pop dx - pop cx - ret ! (carry is already set) -int_ok: - mov t_drive,dl ! save drive - mov dl,dh ! linear address into DX:AX - xor dh,dh - mov bh,dh ! (clear BH too) - pop ax - push cx ! compute #cyls-1 - xchg ch,cl - rol ch,1 - rol ch,1 - and ch,#3 - mov n_cyl,cx ! save #cyls-1 - pop cx - and cx,#0x3f ! CX <- #secs - mov n_secs,cx - div cx ! AX <- track, DX <- sector - inc dl - mov t_sector,dl - xor dx,dx ! divide by #heads - inc bx - div bx ! AX <- cylinder, DX <- head - mov dh,dl ! set up DX (head:drive) - mov dl,t_drive - cmp ax,n_cyl ! valid cylinder number ? - ja linerr3 ! no -> error - xchg ah,al ! build cylinder number - ror al,1 - ror al,1 - or al,t_sector - mov cx,ax - pop bx ! restore BX - and ax,#0x3f ! read beyond end of track ? - add ax,t_secs - cmp ax,n_secs - jna intrk ! no -> go on - mov al,n_secs ! read to end of track - sub al,t_sector - inc al - jmp lrd ! read it -intrk: mov al,t_secs ! read all sectors - - endif - -lrd: push ax ! save AX and BX - push bx - - mov ah,#2 ! - int 0x13 ! read sectors - - pop bx ! restore AX and BX and the linear address - pop ax - pop dx - pop cx - - if linear - - jc linerr ! error -> quit - sub t_secs,al ! adjust sector count - jz lindone ! zero -> done - xor ah,ah ! increase linear address - add cx,ax - adc dh,#0 - xchg ah,al ! move BX - add ah,ah - add bx,ax - jc interr ! crossing segment boundaries -> error - br lnread ! process remaining sectors - -linerr3:pop bx ! pop BX and linear address - pop dx - pop cx -interr: xor ax,ax ! zero indicates internal error - - else - jnc lindone - endif - -linerr: stc ! error - ret -lindone:clc ! no error - ret ! done - - -!-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- - -public table -table: -! .long 0x80000012 -! .byte 1 -! .long 0x07e00000 -! .byte 0 |