CPU Primary Register File
2-9
Architectural Overview
2.3 CPU Primary Register File
The ’C3x provides 28 registers in a multiport register file that is tightly coupled
to the CPU. Table 2–1 lists the register names and functions.
All of the primary registers can be operated upon by the multiplier and ALU and
can be used as general-purpose registers. The registers also have some special
functions. For example, the eight extended-precision registers are especially
suited for maintaining extended-precision floating-point results. The eight auxiliary
registers support a variety of indirect addressing modes and can be used as
general-purpose 32-bit integer and logical registers. The remaining registers
provide such system functions as addressing, stack management, processor
status, interrupts, and block repeat. See Chapter 3,

CPU Registers,

for more
information.

Table 2–1. Primary CPU Registers

Register
Name Assigned Function Section Page
R0 Extended-precision register 0 3.1.1 3-3
R1 Extended-precision register 1 3.1.1 3-3
R2 Extended-precision register 2 3.1.1 3-3
R3 Extended-precision register 3 3.1.1 3-3
R4 Extended-precision register 4 3.1.1 3-3
R5 Extended-precision register 5 3.1.1 3-3
R6 Extended-precision register 6 3.1.1 3-3
R7 Extended-precision register 7 3.1.1 3-3
AR0 Auxiliary register 0 3.1.2 3-4
AR1 Auxiliary register 1 3.1.2 3-4
AR2 Auxiliary register 2 3.1.2 3-4
AR3 Auxiliary register 3 3.1.2 3-4
AR4 Auxiliary register 4 3.1.2 3-4
AR5 Auxiliary register 5 3.1.2 3-4
AR6 Auxiliary register 6 3.1.2 3-4
AR7 Auxiliary register 7 3.1.2 3-4
DP Data-page pointer 3.1.3 3-4
IR0 Index register 0 3.1.4 3-4