Lucent Technologies DSP1611, Information Manual

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Information Manual DSP1611/17/18/27/28/29 DIGITAL SIGNAL PROCESSOR
April 1998
Lucent Technologies Inc.
DRAFT COPY
4-1
4 Instruction Set
All DSP1611, DSP1617, DSP1618, DSP1627, DSP1628, and DSP1629 instructions are 16 bits wide and resemble
C code. The instructions are grouped into seven categories:
Control instructions direct program flow and can be conditionally executed on the basis of the state of internal
flags.
Cache instructions implement low-overhead loops by loading a set of instructions into a cache memory and
repetitively executing them (up to 127 times).
Data move instructions transfer data between registers, memory, and accumulators. Immediate loads of regis-
ters and accumulators are also possible.
Special function instructions perform accumulator operations such as incrementing, rounding, negation, logical
left shifts, and arithmetic right shifts. Special function instructions also permit a single-cycle 32-bit load of an
accumulator from either the p or y register. These special function instructions can be conditionally executed on
the basis of the state of internal flags.
Multiply/ALU instructions are the primary instructions for signal-processing programs that perform multiply/accu-
mulate, logical, and other ALU functions. They also transfer data between memory and registers in the data arith-
metic unit. Flags are set based on accumulator results.
ALU instructions perform operations between two accumulators, between an accumulator and the product regis-
ter, or between an accumulator and an immediate data word. The operations are add, subtract, AND, OR, and
exclusive OR. Flags are set based on accumulator results.
BMU instructions perform full barrel shifting, extraction of an exponent, normalization, and extraction or insertion
of an arbitrary field of bits on the accumulators. An instruction shuffles data between the accumulators and one
of the alternate accumulators. Flags are set based on results.
Note: The only instruction groups that set flags are the multiply/ALU, special function, ALU, and BMU groups.
Also, certain flags are set by the BIO.
The following sections describe the notation, the instruction cycle timing, the addressing modes, the internal flags
used by conditional instructions, and the seven groups of instructions. Appendix B describes each instruction indi-
vidually.