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Chapter 16. D30V Dependent Features

16.2.3. Special Characters

;

and

#

are the line comment characters. Sub instructions may be executed in order, in reverse order,

or in parallel. Instructions listed in the standard one per line format will be executed sequentially

unless you use the

 O

option.

To specify the executing order, use the following symbols:

Sequential with instruction on the left first.

Sequential with instruction on the right first.

||

Parallel

The D30V syntax allows either one instruction per line, one instruction per line with the execution

symbol, or two instructions per line. For example

abs r2,r3  

abs r4,r5

Execute these sequentially. The instruction on the right is in the right container and is executed

second.

abs r2,r3

  abs r4,r5

Execute these reverse sequentially. The instruction on the right is in the right container, and is

executed first.

abs r2,r3 || abs r4,r5

Execute these in parallel.

ldw r2,@(r3,r4) ||

mulx r6,r8,r9

Two line format. Execute these in parallel.

mulx a0,r8,r9

stw r2,@(r3,r4)

Two line format. Execute these sequentially unless

 O

option is used. If the

 O

option is used, the

assembler will determine if the instructions could be done in parallel (the above two instructions

can be done in parallel), and if so, emit them as parallel instructions. The assembler will put them

in the proper containers. In the above example, the assembler will put the

stw

instruction in left

container and the

mulx

instruction in the right container.

stw r2,@(r3,r4)  

mulx a0,r8,r9

Two line format. Execute the

stw

instruction followed by the

mulx

instruction sequentially. The

first instruction goes in the left container and the second instruction goes into right container. The

assembler will give an error if the machine ordering constraints are violated.

stw r2,@(r3,r4)

mulx a0,r8,r9

Same as previous example, except that the

mulx

instruction is executed before the

stw

instruc 

tion.