Commodore Amiga A500 Technical Reference Manual page 149

BITDEF JPCLC,NOPAPER,5
BITDEF JPCLC.ACK.6
BITDEF JPCLC.BUSY.7
;
Bits for PclntReq, PclntGen registers
BITDEF JPCINT.IRQ1.0
;
active high
BITDEF JPCINT.IRQ3.1
;
active low
BITDEF JPCINT,IRQ4.2
;
active low
BITDEF JPCINT,IRQ7,3
;
active low
;
PC side interrupts
JPCKEYINT EQU Sff
;
keycode available
JPCSENDINT EQU Sfc
;
system request
JPCLPTl INT EQU Sf6
;
printer acknowledge
;
Bits for RamSize
BITDEF JRAM,EXISTS,O
;
unset if there is any ram a t all
BITDEF JRAM,2MEG,1
;
set if 2 meg, clear if 112 meg
;
Bits for control register
BITDEF JCNTRL.ENABLEINT,O
;
enable amiga interrupts
BlTDEF JCNTRL, DlSA BL ElNT, 1
;
disable amiga interrupts
BlTDEF JCNTRL.RESETPC.2
;
reset the pc. remember t o strobe
;
ReleasePcReset afterwards
B1 TDEF JCN TRL. CL RPClNT.3
;
turn off all amiga->pc ints (except
;
keyboard
;
Constants for sizes o f various janus regions
JANUSTOTALSIZE EQU 5 1 2* 1 024
;
112 megabyte
JANUSBANKSIZE EQU 128* 1024
;
128K per memory bank
JANUSNUMBANKS EQU 4
;
four memory banks
JANUSBANKMASK EQU $60000
;
mask bits for bank region
janusva1.i-the software data structure for the janus board
Copyright O 1986, Commodore-Amiga Inc., All rights reserved
;
All bytes described here are described in the byte order of the
;
8088. Note that words and longwords
in
these structures will be
;
accessed from the word access space t o preserve the byte order in
;
a word
-
the 8088 will access longwords by reversing the words
:
;
like a 68000 access t o the word access memory
;
JanusMemHead
-
a data structure roughly analogous t o an exec
;
mem chunk.
It is
used t o keep track of memory used between the
;
8088 and the 68000.