Looping Instructions; Move Instructions; Table 6-6 Loop Instruction List - Motorola DSP56800 Manual

Instruction
BFTSTH
BRSET
BRCLR
EORC
NOTC
ORC
Due to instruction pipelining, if an AGU register (Rn, N, SP, or M01) is
directly changed with a bit-field instruction, the new contents may not be
available for use until the second following instruction (see the restrictions
discussed in Section 4.4, "Pipeline Dependencies," on page 4-33).
See Section 8.1.1, "Jumps and Branches," on page 8-2 for other instructions that can be synthesized.
6.4.4

Looping Instructions

The looping instructions establish looping parameters and initiate zero-overhead program looping. They
allow looping on a single instruction (REP) or a block of instructions (DO). For DO looping, the address of
the first instruction in the program loop is saved on the hardware stack to allow no-overhead looping. The
last address of the DO loop is specified as a 16-bit absolute address. No locations in the hardware stack are
required for the REP instruction. The ENDDO instruction is used only when breaking out of the loop;
otherwise, it is better to use
Termination of a DO Loop," on page 8-25.
Table 6-6 lists the loop instructions.
Instruction
DO
ENDDO
REP
6.4.5

Move Instructions

The move instructions move data over the various data buses: CGDB, PGDB, XDB2, and PDB. Move
instructions do not affect the condition code register, except for the limit bit if limiting is performed when
reading a data ALU accumulator register. These instructions do not allow optional data transfers. In
addition to the following move instructions, there are parallel moves that can be used simultaneously with
many of the arithmetic instructions. The parallel moves are shown in Table 6-34 on page 6-29 and
Table 6-5. Bit-Field Instruction List (Continued)
Bit-field test high
Branch if selected bits are set
Branch if selected bits are clear
Logical exclusive OR with immediate data
Logical complement on memory location and registers
Logical inclusive OR with immediate data
NOTE:
. This is discussed in more detail in Section 8.6.6, "Early
MOVE #1,LC
Table 6-6. Loop Instruction List
Start hardware loop
Disable current loop and unstack parameters
Repeat next instruction
Instruction Set Introduction
Description
Description
Instruction Groups
6-9