Registers - Motorola CPU32 Reference Manual

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Figure 2-2 Supervisor Programming Model Supplement

2.2 Registers

Registers D7 to D0 are used as data registers for bit, byte (8-bit), word (16-bit), long-
word (32-bit), and quad-word (64-bit) operations. Registers A6 to A0 and the user and
supervisor stack pointers are address registers that may be used as software stack
pointers or base address registers. Register A7 (shown as A7 and A7' in Figure 2-1)
is a register designation that applies to the user stack pointer in the user privilege level
and to the supervisor stack pointer in the supervisor privilege level. In addition, ad-
dress registers may be used for word and long-word operations. All of the 16 general-
purpose registers (D7 to D0, A7 to A0) may be used as index registers.
MOTOROLA
2-2
16 15 8 7
16 15
16 15
15 8 7
0
Figure 2-1 User Programming Model
16 15
15 8 7
(CCR)
3 2
ARCHITECTURE SUMMARY
0
D0
D1
D2
D3 DATA REGISTERS
D4
D5
D6
D7
0
A0
A1
A2
A3 ADDRESS REGISTERS
A4
A5
A6
0
A7 (USP) USER STACK POINTER
0
PC PROGRAM COUNTER
0
CCR CONDITION CODE REGISTER
0
A7' (SSP) SUPERVISOR STACK
0
SR STATUS REGISTER
0
PC VECTOR BASE REGISTER
0
SFC ALTERNATE FUNCTION
DFC CODE REGISTERS
POINTER
CPU32
REFERENCE MANUAL