Register File - Intel 87C196CA Supplement To User’s Manual

8XC196L X SUPPLEMENT
Device and Hex Address Range
1BFF 1BFF 1BFF
0500 0500 0600
04FF 04FF
0400 0400
03FF 05FF
—
0200 0180
03FF 01FF 017F
0100 0100 0100
00FF 00FF 00FF
0000 0000 0000
NOTES:
1. After a reset, the device fetches its first instruction from 2080H.
2. The content or function of these locations may change in future device revisions, in which case
a program that relies on a location in this range might not function properly.
3.2

REGISTER FILE

Figure 3-1 compares the register file addresses of the 8XC196Lx and 8XC196Kx. The register
file in Figure 3-1 is divided into an upper register file and a lower register file. The upper register
file consists of general-purpose register RAM. The lower register file contains general-purpose
register RAM along with the stack pointer (SP) and the CPU special-function registers (SFRs).
Table 3-2 lists the register file memory addresses. The RALU accesses the lower register file di-
rectly, without the use of the memory controller. It also accesses a windowed location directly
(see "Windowing" on page 3-6). The upper register file and the peripheral SFRs can be win-
dowed. Registers in the lower register file and registers being windowed can be accessed with
register-direct addressing.
The register file must not contain code. An attempt to execute an instruction
from a location in the register file causes the memory controller to fetch the
instruction from external memory.
3-2
Table 3-1. Address Map (Continued)
1BFF
—
0600
05FF
— —
0400
— —
02FF 03FF
0100 0100
00FF 00FF
0000 0000
NOTE
Description
External device (memory
1BFF
or I/O) connected to
0600
address/data bus
05FF
Internal code or data RAM
0400
External device (memory
— or I/O) connected to
address/data bus
Upper register file
03FF
(general-purpose register
0100
RAM)
Lower register file
00FF
(register RAM, stack
0000
pointer, and CPU SFRs)
Addressing
Modes
Indirect or
indexed
Indirect or
indexed
Indirect or
indexed
Indirect,
indexed, or
windowed
direct
Direct,
indirect, or
indexed