Register File; General-Purpose Register Ram; Stack Pointer (Sp) - Intel 8XC196NT User Manual

8XC196NT USER'S MANUAL
4.2.5

Register File

The register file is divided into an upper register file and a lower register file (Figure 4-4). The
upper register file consists of general-purpose register RAM. The lower register file contains ad-
ditional general-purpose register RAM along with the stack pointer (SP) and the CPU special-
function registers (SFRs).
Address
03FFH
Register File
0100H
00FFH
Register File
0000H
Table 4-7 on page 4-13 lists the register file memory addresses. The RALU accesses the lower
register file directly, without the use of the memory controller. It also accesses a windowed loca-
tion directly (see "Windowing" on page 4-15). Only the upper register file and the peripheral
SFRs can be windowed. Registers in the lower register file and registers being windowed can be
accessed with 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.
4-12
Upper
Lower
Figure 4-4. Register File Memory Map
NOTE
Page 00H Address
03FFH
General-purpose
Register RAM
0100H 0100H
00FFH 00FFH
General-purpose
Register RAM
001AH 001AH
0019H 0019H
Stack Pointer
0018H 0018H
0017H 0017H
CPU SFRs
0000H 0000H
A0301-02