Motorola MC68020 - 7.2 COPROCESSOR INSTRUCTION TYPES

MOTOROLA M68020 USER’S MANUAL 7- 7
INTERFACE REGISTER SET
RESERVED
INTERFACE REGISTER SET
RESERVED
INTERFACE REGISTER SET
RESERVED
CPU SPACE ADDRESS
$20000
$2001F
$22000
$2201F
$24000
$2E000
$2E01F
ADDRESS SPACE FOR
C
OPROCESSOR WITH
C
pID = 0
ADDRESS SPACE FOR
C
OPROCESSOR WITH
C
pID = 1
ADDRESS SPACE FOR
C
OPROCESSOR WITH
C
pID = 7
Figure 7-4. Coprocessor Address Map in MC68020/EC020 CPU Space
31
15
0
$
0
0
$
0
4
$
0
8
$0
C
$
1
0
$
1
4
$
1
8
$1
C
O
PERAN
D
(RESERVED)
INSTRUCTION ADDRESS
OPERAND ADDRESS
REGISTER SELECT
C
ONDITIO
N
(RESERVED)
C
OMMAN
D
OPERATION WORD
R
ESTOR
E
S
AV
E
C
ONTRO
L
R
ESPONS
E
16
Figure 7-5. Coprocessor Interface Register Set Map
7.2 COPROCESSOR INSTRUCTION TYPES
The M68000 coprocessor interface supports four categories of coprocessor instructions:
general, conditional, context save, and context restore. The category name indicates the
type of operations provided by the coprocessor instructions in the category. The
instruction category also determines the CIR accessed by the MC68020/EC020 to initiate
instruction and communication protocols between the main processor and the
coprocessor necessary for instruction execution.
During the execution of instructions in the general or conditional categories, the
coprocessor uses the set of coprocessor response primitive codes defined for the M68000
coprocessor interface to request services from and indicate status to the main processor.
During the execution of the instructions in the context save and context