Commodore Amiga A500 Technical Reference Manual page 155

#define JINTB-LPT1 INT (5)
l*
parallel control register */
#define JINTB-COMZINT (6) l* serial control register */
#define JINTB-SYSINT (7)
l*
software int request */
#define JINTF-MINT
#define JINTF-GINT
#define JINTF-CRT1 INT
#define JINTF-CRTZINT
#define JINTF-ENBKB
#define JINTF-LPT1 INT
#define JINTF-COMZINT
#define JINTF-SYSINT
l*
**
The amiga side of the janus board has four sections of its address
space.
**
Three of these parts are different arrangements of the same
memory. The
**
fourth part has the specific amiga accessible 1 0 registers (j i c -
??1.
he he
other three parts all contain the same data, but the data is
arranged
**
in different ways: Byte Access lets the 6 8 k read byte streams
written
**
by the 8088, Word Access lets the 6 8 k read word streams
written by the
**
8088, and Graphic Access lets the 6 8 k read medium res graphics
memory
**
in a more efficient manner (the pc uses packed two bit pixels;
graphic
*
access rearranges these data bits into two bytes, one for each bit
plane).
*/
#define ByteAccessOffset Ox00000
#define WordAccessOffset 0x20000
#define GraphicAccessOffset 0x40000
#define loAccessOffset 0x60000
#define jio-IntReq Oxlffl
l*
read clears, pc
->
amiga
ints
*/
#define jio-PclntReq Oxlff3 l* r/o, amiga
->
pc ints
*/
#define jio-ReleasePcReset Oxlff5 l* r/o, strobe release pc's
reset
*/
#define jio-RamSize OxlfV l* r/o, give ram addresses */
#define jio-IntEna Oxlffg l*
r/w, enables pc int lines
*/
#define jio-PcIntGen Oxlffb / * w / o , b i t = = 0 - > c a u s e
pc int
*/
#define jio-Control Oxlffd
l*
w/o, random control lines
*/