On Wed, Feb 26, 2014 at 7:13 PM, Luís Vitório Cargnini
<[email protected]> wrote:
> On Tue, Feb 25, 2014 at 5:59 PM, Peter Gavin <[email protected]> wrote:
>> On Tue, Feb 25, 2014 at 8:43 PM, Luís Vitório Cargnini
>> <[email protected]> wrote:
>>> Please I need some clarification regarding the 64-bits address space.
>>> for example let's assume the add operation l.addi, in 32 bits it is
>>>
>>> opcode D,A,Imm
>>> 6 5,5,16 (bits)
>>> in 64-bits how would that be ? I'll assume 48b of Immediate ?
>>
>> AFAIK OR64 still uses 32-bit instructions. So immediates are still 16
>> bits.
>>
>> Only the register file, address and data buses are 64 bits.
>>
>> In any case, OR64 hasn't really been developed. Binutils is probably
>> partway there (I tried to keep the cgen stuff as compatible with it as
>> possible) but that's about it.
>
> How could I propose an upgrade to that ? to assume 48-bits ?
>
> Because I would like to push a 64-bit implementation, in fact I'm working on
> it.
Most 64-bit RISC CPUs still use 32-bit instructions, for compactness.
Except for immediate values (both data and pointers), there's usually no need
to grow the instruction size from 32 to 64 bits.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- [email protected]
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
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