dsp56800 Freescale Semiconductor, Inc, dsp56800 Datasheet - Page 87

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

4.2.1
The register-direct addressing modes specify that the operand is in one (or more) of the nine data ALU
registers, seven address registers, or four control registers. The various options are shown in Table 4-3 on
page 4-7.
4.2.1.1
The operand is in one, two, or three data ALU register(s) as specified in the operands or in a portion of the
data bus movement field in the instruction. This addressing mode is also used to specify a control register
operand. This reference is classified as a register reference.
4.2.1.2
The operand is in one of the seven address registers (R0-R3, N, M01, or SP) specified by an effective
address in the instruction. This reference is classified as a register reference.
4.2.2
When an address register is used to point to a memory location, the addressing mode is called address
register indirect. The term indirect is used because the operand is not in the address register itself, but the
contents of the memory location pointed to by the address register. The effective address in the instruction
specifies the address register Rj or SP and the address calculation to be performed. These addressing
Freescale Semiconductor
Register-Direct Modes
Address-Register-Indirect Modes
Any register
Data or Control Register Direct
Address Register Direct
1.
Table 6-16 on page 6-15 and Table 6-15 on page 6-14.
Addressing Mode:
Due to pipelining, if any address register is changed with a MOVE or
bit-field instruction, the new contents will not be available for use as a
pointer until the second following instruction. If the SP is changed, no
LEA or POP instructions are permitted until the second following
instruction.
Register Direct
The register field notations found in the middle column are explained in more detail in
Table 4-3. Addressing Mode — Register Direct
Address Generation Unit
Notation for Register Direct in the
Instruction Set Summary
NOTE:
DDDDD
HHHH
F1DD
HHH
FDD
DD
F1
Rn
Rj
F
1
R0, R1, R2, R3
A, A2, A1, A0
B, B2, B1, B0
Examples
Y, Y1, Y0
OMR, SR
LA, LC
HWS
M01
X0
PC
SP
N
Addressing Modes
4-7