can't read/load memory contents

^^ What is the value of r8? Here you load the contents of address (r8 +

Unfortunately you cannot load a word from an unaligned location anyway. So addr must be divisible by 4.

As I mentioned above lwi needs a word-aligned address. If you really have to load a word beginning at 0x7a810001 you coud read the words at 0x7a810000 and 0x7a810004 and do some shift magic than.

First of all, thanks a lot for your reply!

I followed your advice and loaded the contents of memory 0x7a810010 which is an address divisible by 4. The contents of that address is "bbbbbbbb" given through a testbench file. As a result and based on your instructions, i use the code:

asm(" lwi r8, r0, 0x7a810010");

The following step was to use the 'store' instruction in order to see the contents of the address "0x7a810010" at register 8.

asm(" sw r8,r8(r8) ");

The problem is that i can see the address value on the opb_abus of the mb_opb simulation waveform but i cannot see any data on the opb_dbus. Any idea what could be wrong with the use of instructions? Should i use an OR/ORI? Any problems with 16 or 32 bit values?

Really appreciate your help guys!

First of all, thanks a lot for your reply!

I followed your advice and loaded the contents of memory 0x7a810010 which is an address divisible by 4. The contents of that address is "bbbbbbbb" given through a testbench file. As a result and based on your instructions, i use the code:

asm(" lwi r8, r0, 0x7a810010");

The following step was to use the 'store' instruction in order to see the contents of the address "0x7a810010" at register 8.

asm(" sw r8,r8(r8) ");

The problem is that i can see the address value on the opb_abus of the mb_opb simulation waveform, but i cannot see any data on the opb_dbus (see only undefined value or series of 'x'). Any idea what could be wrong with the use of instructions? Should i use an OR/ORI? Any problems with 16 or 32 bit values?

Really appreciate your help guys!

Ah yes. This should be sw r8, rA, rB where the address (rA + rB) must be word-aligned again--and 0xbbbbbbbb * 2 isn't. You could also use an IMM, so you don't need to fill rA and rB: swi r8, r0, addr

Good luck.

HTH

I see your point Minh thank you very much.

One more think. What do you mean that the data 0xbbbbbbbb are not word- aligned? Should be maximum up to 0x80000000? I'll follow your advice! Thanks again

The hardware supported data types for MicroBlaze are byte (8 bits), half-word (16 bits) and word (32 bits). Data access must be aligned, which means it must be on boundaries that depend on the type. Since a word has the size of 4 bytes the boundaries lie at addresses which are divisible by

No, each address space has a 32-bit range. So you can handle up to 4 GB of memory.

(snip)

Is the address really X'BBBBBBBB'? Or is the b supposed to mean something else? If it is really the hex digit B then yes, the address is odd. Otherwise, it doesn't seem like a likely address.

-- glen