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to the peripheral that the data transfer is complete. If the
src_inc
bit in the channel control registers is
set to incrementing, the DMAC updates source address registers after it executes
DMALDP<S|B>
.
Figure 16-12: DMALDP<S|B> Instruction Encoding
1
7 6
5 4 3 2 1 0
15
11 10 9 8
periph[4:0]
0
0
0
0
0
0
0
1
1 bs
Assembler syntax
DMALDP<S|B> <peripheral>
where:
<S>
When S is present, the assembler sets
bs
to 0. The instruction is conditional on the state of the
request_type
flag:
•
request_type
= Single
The DMAC performs a
DMALDP
instruction and it sets
arlen[3:0]
=0x0 so that the AXI read transaction
length is one. The DMAC ignores the value of the src_burst_len field in the channel control registers.
•
request_type
= Burst
The DMAC performs a
DMANOP
.
<B>
When B is present, the assembler sets
bs
to 1. The instruction is conditional on the state of the
request_type
flag:
•
request_type
= Single
The DMAC performs a
DMANOP
.
•
request_type
= Burst
The DMAC performs a load using a burst DMA transfer.
<peripheral>
5-bit immediate, value 0-31.
The DMAC sets the value of the
request_type
flag when it executes a
DMAWFP
instruction.
Note:
Operation
You can only use this instruction in a DMA channel thread. Execution of the instruction is conditional on
the state of the
request_type
flag matching that of the instruction.
DMALP
Loop instructs the DMAC to load an 8-bit value into the loop counter register you specify.
This instruction indicates the start of a section of instructions, and you set the end of the section using the
DMALPEND
instruction. The DMAC repeats the set of instructions that you insert between
DMALP
and
DMALPEND
until the value in the loop counter register reaches zero.
The DMAC saves the value of the PC for the instruction that follows
DMALP
. After the DMAC
executes
DMALPEND
, and the loop counter register is not zero, this enables it to execute the first
instruction in the loop.
Note:
Altera Corporation
DMA Controller
16-33
DMALP
cv_54016
2013.12.30