Subtract Using Halfword Addressing Mode

 

SUBAH

 

 

 

Subtract Using Halfword Addressing Mode

 

 

 

 

 

 

 

 

SUBAH

 

 

 

 

 

 

 

 

 

 

Syntax

 

 

 

 

SUBAH (.unit) src2, src1, dst

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

.unit = .D1 or .D2

 

 

 

 

 

 

 

 

 

 

 

 

Compatibility

 

 

C62x, C64x, C67x, and C67x+ CPU

 

 

 

 

 

 

 

 

 

 

Opcode

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

31

29

28

27

23

22

18

17

13

12

7

6

5

4

3

2

1

0

creg

z

dst

src2

src1

op

1 0

0 0 0

s p

3

1

5

5

5

6

1

1

 

 

 

 

 

 

 

 

 

 

 

Opcode map field used...

For operand type...

Unit

Opfield

 

 

 

 

 

 

 

 

 

 

 

 

src2

sint

.D1, .D2

11 0101

 

 

 

 

src1

sint

 

 

 

 

 

 

dst

sint

 

 

 

 

 

 

src2

sint

.D1, .D2

11 0111

 

 

 

 

src1

ucst5

 

 

 

 

 

 

dst

sint

 

 

 

 

 

 

 

 

 

 

 

Description

Execution

Pipeline

src1 is subtracted from src2 using the halfword addressing mode specified for src2. The subtraction defaults to linear mode. However, if src2 is one of A4−A7 or B4−B7, the mode can be changed to circular mode by writing the appropri- ate value to the AMR (see section 2.7.3, page 2-10). src1 is left shifted by 1. The result is placed in dst.

if (cond) src2 −a src1 dst else nop

Pipeline

E1

Stage

 

 

Read

src1, src2

Written

dst

Unit in use

.D

 

 

Instruction Type

Single-cycle

Delay Slots

0

See Also

SUB, SUBAB, SUBAW

SPRU733

Instruction Set

3-255

Page 315
Image 315
Texas Instruments TMS320C67X/C67X+ DSP manual Subtract Using Halfword Addressing Mode, Subah, SUB, SUBAB, Subaw