Texas Instruments TMS320C2XX User Manual

Page 552

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F-15

Glossary

MSTACK:

See

micro stack.

multiplier:

A part of the CPU that performs 16-bit

×

16-bit multiplication and

generates a 32-bit product. The multiplier operates using either signed
or unsigned 2s-complement arithmetic.

N

next AR:

See

next auxiliary register.

next auxiliary register:

The register that will be pointed to by the auxiliary

register pointer (ARP) when an instruction that modifies ARP is finished
executing. See also

auxiliary register; current auxiliary register.

NMI:

A hardware interrupt that uses the same logic as the maskable inter-

rupts but cannot be masked. It is often used as a soft reset. See also
maskable interrupt; nonmaskable interrupt.

nonmaskable interrupt:

An interrupt that can be neither masked by the in-

terrupt mask register (IMR) nor disabled by the INTM bit of status register
ST0.

NPAR:

Next program address register. Part of the program-address genera-

tion logic. This register provides the address of the next instruction to the
program counter (PC), the program address register (PAR), the micro
stack (MSTACK), or the stack.

O

OE:

Receiver register overrun indicator bit. Bit 9 of the I/O status register

(IOSR); indicates whether overrun has occurred in the receiver of the
asynchronous serial port (that is, whether an unread character in the
ADTR has been overwritten by a new character).

operand:

A value to be used or manipulated by an instruction; specified in

the instruction.

operand-fetch phase:

The third phase of the pipeline; the phase in which

an operand or operands are fetched from memory. See also

pipeline;

instruction-fetch phase; instruction-decode phase; instruction-execute
phase.

output shifter:

32- to 16-bit barrel left shifter. Shifts the 32-bit accumulator

output from 0 to 7 bits left for quantization management, and outputs ei-
ther the 16-bit high or low half of the shifted 32-bit data to the data write
bus (DWEB).

Glossary

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