Throw DOS api away, re-layout memory to fit CP/M model

kernel/drive.asm

@@ -1,53 +0,0 @@
-; drive table
-%define drivetab_type    0x00 ; BYTE  0=unassigned, 1=BIOS/CHS, 2=BIOS/LBA
-%define drivetab_num     0x01 ; BYTE  DL number
-
-; CHS data for type=1
-; Might be reused for driver address
-%define drivetab_heads   0x02 ; WORD  CHS heads
-%define drivetab_spt     0x04 ; WORD  CHS sectors per track
-
-%define drivetab_sectors 0x06 ; DWORD total number of sectors
-%define drivetab_offset  0x0A ; DWORD partition offset
-%define drivetab_size    0x0E
-
-drive_table:
-  dw 0
-.count:
-  dw 4
-
-; DI is incremented for the space taken
-; IN	ES:DI
-drive_setup:
-  xor cx, cx
-  mov [drive_table], di
-  mov al, drivetab_size
-  mov ah, BYTE [drive_table.count]
-  mul ah
-  xchg cx, ax
-  ; this increments DI and also fills table with zeros
-  rep stosb
-  ret
-
-; Load a drive table entry
-; IN    DL      drive number
-; OUT   DS:SI   ptr to table item
-drive_load:
-  ; bail out if number too high
-  cmp dl, [cs:drive_table.count]
-  jnc .err
-
-  push cs
-  pop ds
-  mov si, [drive_table]
-
-  push ax
-  mov al, drivetab_size
-  mul dl
-  add si, ax
-  pop ax
-
-  ret
-.err:
-  stc
-  ret