dsp56800 Freescale Semiconductor, Inc, dsp56800 Datasheet - Page 146

• Manufacturer Part Number: dsp56800
• Description: 16-bit Digital Signal Controllers
• Manufacturer: Freescale Semiconductor, Inc

Instruction Set Introduction
6.6.1
There are many different register fields used within the instruction summary tables. These will be grouped
into sets that are more easily understood.
Table 6-14 shows the register set available for the most important move instructions. Sometimes the
register field is broken into two different fields — one where the register is used as a source (src), and the
other where it is used as a destination (dst). This is important because a different notation is used when an
accumulator is being stored without saturation. Also see the register fields in Table 6-15, which are also
used in move instructions as sources and destinations within the AGU.
In some cases, the notation used when specifying an accumulator determines whether or not saturation is
enabled when the accumulator is being used as a source in a move or parallel move instruction. Refer to
Section 3.4.1, “Data Limiter,” on page 3-26 and Section 3.2, “Accessing the Accumulator Registers,” on
page 3-7 for information.
Table 6-15 shows the register set available for use as pointers in address-register-indirect addressing
modes. This table also shows the notation used for AGU registers in AGU arithmetic operations.
6-14
Register Field
Register Field
DDDDD
HHHH
HHH
M01
Register Field Notation
Rn
Rj
N
Registers in This Field
Table 6-14. Register Fields for General-Purpose Writes and Reads
Registers in This Field
R0, R1, R2, R3
A, A2, A1, A0
B, B2, B1, B0
A, B, A1, B1
A, B, A1, B1
R0, R1, R2, R3
X0, Y0, Y1
X0, Y0, Y1
Y1, Y0, X0
OMR, SR
R0-R3, N
LA, LC
Table 6-15. Address Generation Unit (AGU) Registers
N, SP
HWS
M01
R0–R3
M01
SP
N
DSP56800 Family Manual
Seven data ALU registers — two accumulators, two 16-bit MSP
portions of the accumulators, and three 16-bit data registers
Seven data ALU and five AGU registers
All CPU registers
Five AGU registers available as pointers for addressing and as sources
and destinations for move instructions
Four pointer registers available as pointers for addressing
One index register available only for indexed addressing modes
One modifier register
Comments
Comments
Freescale Semiconductor