Store Word to Memory With a 5-Bit Unsigned Constant Offset or Register Offset

STW

 

 

 

 

 

Store Word to Memory With a 5-Bit Unsigned Constant Offset or

 

 

STW

 

 

 

 

 

 

 

 

 

 

 

Register Offset

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Syntax

 

 

 

 

 

Register Offset

 

 

 

Unsigned Constant Offset

 

 

 

 

 

 

 

 

 

STW (.unit) src, *+baseR[offsetR]

 

STW (.unit) src, *+baseR[ucst5]

 

 

 

 

 

 

 

 

.unit = .D1 or .D2

 

 

 

 

 

 

 

 

 

 

 

 

 

Compatibility

 

 

 

C62x, C64x, C67x, and C67x+ CPU

 

 

 

 

 

 

 

 

 

 

 

Opcode

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

31

29

28

27

23

22

18

17

13

12

9

8

7

6

4

3

2

1

0

creg

z

src

baseR

offsetR/ucst5

mode

0 y 1 1 1 0 1 s p

3 1555411 1

Description

Stores a word to memory from a general-purpose register (src). Table 3−11

 

(page 3-33)describes the addressing generator options. The memory

 

address is formed from a base address register (baseR) and an optional offset

 

that is either a register (offsetR) or a 5-bit unsigned constant (ucst5).

 

offsetR and baseR must be in the same register file and on the same side as

 

the .D unit used. The y bit in the opcode determines the .D unit and register

 

file used: y = 0 selects the .D1 unit and baseR and offsetR from the A register

 

file, and y = 1 selects the .D2 unit and baseR and offsetR from the B register

 

file.

 

offsetR/ucst5 is scaled by a left-shift of 2 bits. After scaling, offsetR/ucst5 is

 

added to or subtracted from baseR. For the preincrement, predecrement,

 

positive offset, and negative offset address generator options, the result of the

 

calculation is the address to be accessed in memory. For postincrement or

 

postdecrement addressing, the value of baseR before the addition or subtrac-

 

tion is sent to memory.

 

The addressing arithmetic that performs the additions and subtractions

 

defaults to linear mode. However, for A4−A7 and for B4−B7, the mode can be

 

changed to circular mode by writing the appropriate value to the AMR

 

(see section 2.7.3, page 2-10).

 

For STW, the entire 32-bits of the src register are stored. src can be in either

 

register file, regardless of the .D unit or baseR or offsetR used. The s bit deter-

 

mines which file src is read from: s = 0 indicates src will be in the A register file

 

and s = 1 indicates src will be in the B register file. The r bit should be cleared

 

to 0.

SPRU733

Instruction Set

3-245

Page 305
Image 305
Texas Instruments TMS320C67X/C67X+ DSP manual Stw, Register Offset