Instruction Groups; Arithmetic Instructions; Table 6-3 Arithmetic Instructions List - Motorola DSP56800 Manual

Instruction Set Introduction
6.4

Instruction Groups

The instruction set is divided into the following groups:
• Arithmetic
• Logical
• Bit manipulation
• Looping
• Move
• Program control
Each instruction group is described in the following subsections. In addition, Section 6.5.2, "LSLL Alias,"
includes a useful summary for every instruction and the addressing modes and operand registers allowed
for each instruction. Detailed information on each instruction is given in Appendix A, "Instruction Set
Details."
6.4.1

Arithmetic Instructions

The arithmetic instructions perform all of the arithmetic operations within the data ALU. They may affect
a subset or all of the condition code register bits. Arithmetic instructions are typically register based
(register-direct addressing modes are used for operands) so that the data ALU operation indicated by the
instruction does not use the CGDB or the XDB2, although some instructions can also operate on
immediate data or operands in memory.
Optional data transfers (parallel moves) may be specified with many arithmetic instructions. This allows
for parallel data movement over the CGDB and over the XDB2 during a data ALU operation. This allows
new data to be pre-fetched for use in following instructions and results calculated by previous instructions
to be stored. Arithmetic instructions typically execute in one instruction cycle, although some of the
operations may take additional cycles with different operand addressing modes. The arithmetic
instructions are the only class of instructions that allow parallel moves.
In addition to the arithmetic shifts presented here, other types of shifts are also available in the logical
instruction group. See Section 6.4.2, "Logical Instructions." Table 6-3 lists the arithmetic instructions.
Instruction
ABS
ADC
ADD
ASL
ASLL
ASR
ASRAC
ASRR
6-6
Table 6-3. Arithmetic Instructions List
Description
Absolute value
Add long with carry
Arithmetic shift left (36-bit)
Arithmetic multi-bit shift left
Arithmetic shift right (36-bit)
Arithmetic multi-bit shift right with accumulate
Arithmetic multi-bit shift right
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