Motorola M68000 - 2.2 DATA TYPES AND ADDRESSING MODES

MOTOROLA M68000 8-/16-/32-BIT MICROPROCESSOR USER’S MANUAL 2-3
tables. The SFC and DFC registers allow the supervisor to access user data space or
emulate CPU space cycles.
31 16 15 0
15 8 7 0
A7'
(SSP)
SUPERVISOR STACK
POINTER
CCR
SR STATUS REGISTER
31 0
VBR VECTOR BASE REGISTER
20
SFC
DFC
ALTERNATE FUNCTION
CODE REGISTERS
Figure 2-3. Supervisor Programmer's Model Supplement
(MC68010)
2.1.3 Status Register
The status register (SR),contains the interrupt mask (eight levels available) and the
following condition codes: overflow (V), zero (Z), negative (N), carry (C), and extend (X).
Additional status bits indicate that the processor is in the trace (T) mode and/or in the
supervisor (S) state (see Figure 2-4). Bits 5, 6, 7, 11, 12, and 14 are undefined and
reserved for future expansion
T
S
III
XNZVC
210
15 13 10 8 4 0
TRACE MODE
SUPERVISOR
STATE
INTERRUPT
MASK
EXTEND
NEGATIVE
ZERO
OVERFLOW
CARRY
CONDITION
CODES
SYSTEM BYTE USER BYTE
Figure 2-4. Status Register
2.2 DATA TYPES AND ADDRESSING MODES
The five basic data types supported are as follows:
1. Bits
2. Binary-Coded-Decimal (BCD) Digits (4 Bits)
3. Bytes (8 Bits)
4. Words (16 Bits)
5. Long Words (32 Bits)
Frees
cale Semiconductor,
I
Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
nc...