BIOS RAM locations


 * Memory card related:
 * BIOS_CRDF      equ $10FDC4 ;byte: function to perform when calling BIOSF_CRDACCESS, see below table
 * BIOS_CRDRESULT equ $10FDC6 ;byte: 00 on success, else 80+ and encodes the error, see below table
 * BIOS_CRDPTR    equ $10FDC8 ;longword: pointer to read from/write to
 * BIOS_CRDSIZE   equ $10FDCC ;word: how much data to read/write from/to card
 * BIOS_CRDNGH    equ $10FDCE ;word: usually game NGH. Unique identifier for the game that 'owns' the save file
 * BIOS_CRDFILE   equ $10FDD0 ;word: each NGH has up to 16 save 'files' associated with


 * Calendar, only on MVS (in BCD)
 * BIOS_YEAR      equ $10FDD2 ;last 2 digits of year
 * BIOS_MONTH     equ $10FDD3
 * BIOS_DAY       equ $10FDD4
 * BIOS_WEEKDAY   equ $10FDD5 ;Sunday = 00, Monday = 01 ... Saturday = 06
 * BIOS_HOUR      equ $10FDD6 ;24 hour time
 * BIOS_MINUTE    equ $10FDD7
 * BIOS_SECOND    equ $10FDD8


 * BIOS_SELECT_TIMER equ $10FDDA ;Byte: game start countdown
 * BIOS_DEVMODE     equ $10FE80 ;Byte: non-zero for developer mode


 * Upload to DRAM
 * BIOS_UPDEST    equ $10FEF4 ;longword: destination address (!)
 * BIOS_UPSRC     equ $10FEF8 ;longword: source address
 * BIOS_UPSIZE    equ $10FEFC ;longword: size
 * BIOS_UPZONE    equ $10FEDA ;byte: zone (0=PRG, 1=FIX, 2=SPR, 3=Z80, 4=PCM, 5=PAT)
 * BIOS_UPBANK    equ $10FEDB ;byte: bank