Commodore Amiga A1000, Hardware Reference Manual

Page: 17 / 380

NOTE
The offset values of the registers are the addresses that the Copper must use to talk to
the registers. For example, in assembler:
INCLUDE "exec/types.i"
INCLUDE "hardware/custom.i"
XREF custom ; External reference
Start: lea _custom,a0 ; Use a0 as base register
move.w #$7FFF,intena(a0) ; Disable all interrupts
In C, you would use the structure definitions in hardware/custom.h For
example:
#include "exec/types.h"
#include "hardware/custom.h"
extern struct Custom custom;
/* You may need to define the above external as
** extern struct Custom far custom;
** Check you compiler manual.
*/
main()
{
custom.intena = 0x7FFF; /* Disable all interrupts */
}
The Amiga hardware include files are generally supplied with your compiler or assembler.
Listings of the hardware include files may also be found in the Addison-Wesley Amiga ROM
Kernel Manual "Includes and Autodocs". Generally, the include file label names are very
similar to the equivalent hardware register list names with the following typical
differences.
o Address registers which have low word and high word components are generally listed
as two word sized registers in the hardware register list, with each register name
containing either a suffix or embedded "L" or "H" for low and high. The include file label
for the same register will generally treat the whole register as a longword (32 bit)
register,
and therefore will not contain the "L" or "H" distinction.
o Related sequential registers which are given individual names with number suffixes in
the hardware register list, are generally referenced from a single base register definition
in the include files. For example, the color registers in the hardware list (COLOR00,
COLOR01, etc.) would be referenced from the "color" label defined in "hardware/custom.i"
(color+0, color+2, etc.).
o Examples of how to define the correct register offset can be found in the hw_examples.i
file listed in Appendix J.
- 8 Introduction -