Apac – Texas Instruments TMS320C2XX User Manual

Page 190

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Add PREG to Accumulator

APAC

7-37

Assembly Language Instructions

Syntax

APAC

Operands

None

APAC

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

1

0

1

1

1

1

1

0

0

0

0

0

0

1

0

0

Execution

Increment PC, then ...
(ACC) + shifted (PREG)

ACC

Status Bits

Affected by

Affects

PM and OVM

C and OV

This instruction is not affected by SXM.

Description

The contents of PREG are shifted as defined by the PM status bits of the ST1
register (see Table 7–7) and added to the contents of the accumulator. The re-
sult is placed in the accumulator. APAC is not affected by the SXM bit of the
status register. PREG is always sign extended. The task of the APAC instruc-
tion is also performed as a subtask of the LTA, LTD, MAC, MACD, MPYA, and
SQRA instructions.

Table 7–7. Product Shift Modes

PM Bits

Bit 1

Bit 0

Resulting Shift

0

0

No shift

0

1

Left shift of 1 bit

1

0

Left shift of 4 bits

1

1

Right shift of 6 bits

Words

1

Cycles for a Single APAC Instruction

ROM

DARAM

SARAM

External

1

1

1

1+p

Cycles for a Repeat (RPT) Execution of an APAC Instruction

ROM

DARAM

SARAM

External

n

n

n

n+p

Opcode

Cycles

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