18.104.22.168 Special Characters
A semicolon (`;') can be used anywhere on a line to start a
comment that extends to the end of the line.
If a `#' appears as the first character of a line, the whole line
is treated as a comment, but in this case the line could also be a
logical line number directive (see Comments) or a preprocessor
control command (see Preprocessing).
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.
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) ||
- Two-line format. Execute these in parallel.
- 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) ->
- 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
stw r2,@(r3,r4) <-
- Same as previous example, except that the `mulx' instruction is
executed before the `stw' instruction.
Since `$' has no special meaning, you may use it in symbol names.