------------------------------------------
    Raspberry Pi Pico  SYM-1 Emulator
------------------------------------------

Comms
-----
F001 Data Out Register
F004 Data In Register

xxx STATUS RxC0 (BIT7) TxC0 (BIT 6)   (doesnt exist in this build, as it isnt an emulated ACIA)

Trig
----
Trig routines located F5C0 - F6EE
To patch, start Basic J0 / G C000
Exit to monitor with q=usr(&"8035",0)
G F5C0 to patch Trig routines
G 0 to re-enter Basic

Zero Page locations C4 & C5 contain the vector to the patch, 
which will get overwritten if Basic is restarted with J0 / G C000 


--------------------------------------------------------
 SYSRAM DEFAULT CHANGES IN SUPERMON (within 8000 Block)
--------------------------------------------------------

insvec 4c xx xx
invec   4C 0B F0
outvec  4C 23 F0 
urcvec	4C 1D F0  Unrecognised command handler. (Yet to be added)

8FE0- 4C 0B F0 4C 23 F0 4C 30 F0    <<  Supermon



-----------------------------------------------------------------------------------------------
 1541DOS CHANGES TO REDIRECT TO PATCHES WHICH FIX SD2IEC AND PI1541 ISSUES (within 9000 Block)
-----------------------------------------------------------------------------------------------

9278 20 XX F0       replace with correct address for replacement HEX2AD routine

9295 20 XX F0       replace with correct address for replacement CHR.OUT routine

---------------------------
  INIT ACIA (not used)
---------------------------

F000- EA EA     0010       

F002- EA EA EA  0011

F004           

F005- EA EA     0012  init:         

F007- EA EA EA  0013           

F00A- 60        0014           


--------------------------
 input (checks TECHO bit)
--------------------------


F00B- AD 04 F0  0020 input:     lda $F004

F00E- EA EA     0021            Nop

F010- F0 F9     0022            beq input:

F012- EA EA EA  0023            Nop
F015- 2C 53 A6	0024	        BIT $A653
F018- 10 03	0025		BPL EXIT:
F01A- 20 23 F0 	0026	        JSR $F023
F01D- 60	0027 EXIT:	RTS



--------
 OUTPUT
--------

F023- EA        0040 out:       pha

F024- EA EA EA  0041 out1:      Nop

F027- EA EA     0042            Nop

F029- EA EA     0043            Nop

F02B- EA        0044            Nop

F02C- 8D 01 F0  0045            sta $F001

F02F- 60        0046            rts

                0200            .en


-----------------
 insvec handler
-----------------
F030 clc
F031 rts

------------------------------------------------------------------------------------------------------------------------
following not actually used. Was intended as means to initialise ACIA on reset, but turns out it doesnt need to be done.
------------------------------------------------------------------------------------------------------------------------
F050 jsr init
     jmp monent

--------------------------------------------
  Future 1541DOS replacement routines
to address incorrect block size calculation
---------------------------------------------
F060 





