microblaze data transfer

[C.Amendola]

I'm planning to use Microblaze in my project without using DMA devices. It
seems than Microblaze don't have any instruction like "read and auto-
increment register" so if I have to transfer data from a location to
another I have to implicitaly increment pointer. Anyone knows if there is
some solution that allows to transfer data with the lowest number of
cycles?

 

[Goran Bilski]

Hi,

Since MicroBlaze branches on register values you can first load a
register with the length.
MicroBlaze also have an address mode which is address = regA + regB.
I would also move from the end to the beginning like this

addi r5,r0,#Src_Addr
addi r6,r0,#Dest_Addr
addi r7,r0,#(4*(Nr_of_Words-1)
..loop
lw r8,r5,r7
sw r8,r6,r7
bneid r7,loop
addi r7,r7,-4

This will create a loop with 1 load, 1 load, 1 branch and 1 decrement.
The number of clock cycles depends on the latency to the memory but it
will be 2 memory access + 3 clock cycles if the code is executed from
the LMB memory.

Göran Bilski

C.Amendola wrote:

I'm planning to use Microblaze in my project without using DMA
devices. It seems than Microblaze don't have any instruction like
"read and auto- increment register" so if I have to transfer data from
a location to another I have to implicitaly increment pointer. Anyone
knows if there is some solution that allows to transfer data with the
lowest number of cycles?