Moving xbios to lower address?

[clth]

Hello,

 

i would like to move xbios to start on page 4 instead of default 7.

 

My guess is that it can be done according memory layout but i just cant figure out any xbios.cfg settings which do work same as default one plus shift. Thanks.

[rensoup]

I have it at $600 but I guess it should be ok at $400 ?

 

I just build this file with MADS which becomes xbios.cfg (25 bytes) to be placed inside your ATR

 

xbios43cfg.asm:

	opt h-

		icl "xbios43.inc"

.byte   $43             ; config for v4.3 version
.byte c'LAUNCHEROBX'    ; autorun file fname
.byte   >xBIOS_BASE          ; xB adress for relocator
.byte   >(xBIOS_BASE-$100)   ; xB buffer adress for relocator
.word   $02e2           ; INITAD
.word   $02e0           ; RUNAD
.word   $0000           ; custom I/O module - $0000 means use internal xB SIO
.word   $0000           ; relocator for custom I/O module
.byte   $ff             ; PORTB - you can't swith off BASIC this way
.byte   $40             ; NMIEN - config at start
.byte   $80             ; IRQEN - config at start

 

xbios43.inc is where you set the address (xBIOS_BASE) to be included in the file above and in your project (to call xBIOS_OPEN_FILE,...)

xBIOS_BASE                 =$600		; // must update LORAM_TOP ( can't just equal it to LORAM_TOP because this file is also included in xbioscfg.asm which gets rebuilt into xbios.cfg)
xBIOS_SIZE                 =$400
xBIOS_VERSION              =xBIOS_BASE+$02
xBIOS_RENAME_ENTRY        = xBIOS_BASE+$03
xBIOS_LOAD_FILE            = xBIOS_BASE+$06
xBIOS_OPEN_FILE            = xBIOS_BASE+$09
xBIOS_LOAD_DATA            = xBIOS_BASE+$0c
xBIOS_WRITE_DATA           = xBIOS_BASE+$0f
xBIOS_OPEN_CURRENT_DIR    = xBIOS_BASE+$12
xBIOS_GET_BYTE             =xBIOS_BASE+$15
xBIOS_PUT_BYTE             =xBIOS_BASE+$18
xBIOS_FLUSH_BUFFER        = xBIOS_BASE+$1b
xBIOS_SET_LENGTH           = xBIOS_BASE+$1e
xBIOS_SET_INIAD            = xBIOS_BASE+$21
xBIOS_SET_FILE_OFFSET     = xBIOS_BASE+$24
xBIOS_SET_RUNAD            = xBIOS_BASE+$27
xBIOS_SET_DEFAULT_DEVICE  = xBIOS_BASE+$2a
xBIOS_OPEN_DIR             =xBIOS_BASE+$2d
xBIOS_LOAD_BINARY_FILE    = xBIOS_BASE+$30
xBIOS_OPEN_DEFAULT_DIR    = xBIOS_BASE+$33
xBIOS_SET_DEVICE           = xBIOS_BASE+$36
xBIOS_RELOCATE_BUFFER     = xBIOS_BASE+$39
xBIOS_GET_ENTRY            = xBIOS_BASE+$3c
xBIOS_OPEN_DEFAULT_FILE   = xBIOS_BASE+$3f
xBIOS_READ_SECTOR         = xBIOS_BASE+$42
xBIOS_FIND_ENTRY           = xBIOS_BASE+$45
xBIOS_SET_BUFFER_SIZE     = xBIOS_BASE+$48

xDIRSIZE        = xBIOS_BASE+$3e5 ; current directory size in sectors (1 byte)
xSPEED          = xBIOS_BASE+$3e6 ; STANDARD SPEED (1 byte)
xHSPEED         = xBIOS_BASE+$3e7 ; ULTRA SPEED (1 byte)
xIRQEN          = xBIOS_BASE+$3e8 ; User IRQ (1 byte)
xAUDCTL         = xBIOS_BASE+$3e9 ; AUDCTL
xFILE           = xBIOS_BASE+$3ea ; File handle (2 bytes)
xDIR            = xBIOS_BASE+$3ec ; Root directory handle (2 bytes)
xIOV            = xBIOS_BASE+$3ee ; I/O module entry (2 bytes)
xBUFFERH        = xBIOS_BASE+$3f0 ; Buffer adr hi byte (1 byte)
xBUFSIZE        = xBIOS_BASE+$3f1 ; Buffer size lo byte $100-SIZE (1 byte)
xDAUX3          = xBIOS_BASE+$3f2 ; Buffer offset (1 byte)
xSEGMENT        = xBIOS_BASE+$3f3 ; Bytes to go in binary file segment (2 bytes)
xNOTE           = xBIOS_BASE+$3f5 ; File pointer (3 bytes)
xDEVICE         = xBIOS_BASE+$3fc ; Device ID
xDCMD           = xBIOS_BASE+$3fd ; CMD (1 byte)
xDAUX1          = xBIOS_BASE+$3fe ; Sector lo byte (1 byte)
xDAUX2          = xBIOS_BASE+$3ff ; Sector hi byte (1 byte)

 

and that should do it...

 

xbios.cfg xbios43cfg.asm xbios43.inc

[clth]

Thanks alot for detailed answer, i forgot to adjust my base offset for xbios area.

 

It seems that it has something to do with I/O location which by value reported by xbios menu - gets configured to pretty random address which is often occupied my program after load.

 

This address can be overridden in config, default one seem to be 0x03C0 which possibly can cause overlap but there is no documentation and bit too low level stuff for me unfortunately.

 

With this xbios.cfg which should equal xbios defaults you wrote I can get program loaded but keyboard is not working at all. Without xbios.cfg, just with xbios builtin defaults is everything ok.

00000000  43 58 41 55 54 4f 52 55  4e 20 20 20 08 07 e2 02  |CXAUTORUN   ....|
00000010  e0 02 00 00 00 00 ff 40  80                       |.......@.|

 

Edited July 10, 2020 by clth

[rensoup]

On 7/11/2020 at 1:13 AM, clth said:

With this xbios.cfg which should equal xbios defaults you wrote I can get program loaded but keyboard is not working at all. Without xbios.cfg, just with xbios builtin defaults is everything ok.

Oh yeah I probably disabled the IRQ... specifically to kill the keyboard handler!

 

On 7/10/2020 at 1:14 AM, rensoup said:

.byte $80 ; IRQEN - config at start

 

You should probably set this back to whatever value was in your config

[clth]

Kind of figured out right xbios settings after all, thanks.

[xxl]

The xbios file starts with a configuration, so if you don't want to use an external file, you can edit the beginning of the xBIOS file (just after the header there is a configuration in the same format).

If you are bothered by the menu, you can delete it - just cut off the 5th and 6th block of the xBIOS file (it is not needed if you are not using the MENU and operating system for I / O)