Example, Instruction formats and opcodes, Instruction fields – Freescale Semiconductor StarCore SC140 User Manual

Page 491

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IFc

SC140 DSP Core Reference Manual

A-177

Status and Conditions that Affect Instruction

Status and Conditions Changed by Instruction

None.

Example

ift move.w #>$ffff,d0

Instruction Formats and Opcodes

Note:

These instructions are encoded into either a one-word or two-word prefix.

Instruction Fields

ccc:

Conditional execution of the entire execution set

In the following table, true/false relates to the state of the T bit in SR: D0, D1, D2, and D3 are DALU
instructions. A0 and A1 are AGU instructions. The numbers relate to the relative offset of the instruction
from the beginning of the set, as encoded. For example, a full execution set might be D0, D1, D2, D3, A0,
A1.

000—Unconditionally executed
001—If true (D0,D2,A0), if false (D1,D3,A1)
010—If true, all the set
011—If false, all the set
100—Reserved
101—Reserved
110—If true (D0,D2,A0), always (D1,D3,A1)
111—If false (D0,D2,A0), always (D1,D3,A1)

Register Address

Bit Name

Description

SR[1]

T

True bit

Register/Memory Address

Before

After

SR

$00E4 0002

$00E4 0002

immediate

$FFFF

L0:D0

$0:$FF FFFF FFFF

Instruction

Words Cycles Type

Opcode

15

8

7

0

IFc

1

1

4

1

0

0

1

a

a

a

0

1

1

0

p

j

c

c

c

15

8

7

0

IFc

2

1

4

0

0

1

1

a

a

a

0

H

t

h

p

j

c

c

c

1

0

1

b

B

e

E

T

b

B

e

E

b

B

e

E

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