On 19 December 2013 06:01, Peter Crosthwaite
<peter.crosthwaite@xxxxxxxxxx> wrote:
> On Wed, Dec 18, 2013 at 1:12 AM, Peter Maydell <peter.maydell@xxxxxxxxxx> wrote:
>> + *key = ENCODE_AA64_CP_REG(r2->cp, r->crn, crm,
>> + r->opc0, opc1, opc2);
>
> You have mixed terminology here with "opc" and "op". Should they be
> unionised in ARMCPRegInfo?
>
> union {
> uint8_t op1;
> uint8_t opc1;
> };
That seems pretty ugly to me. The terminology mixing is kind of
inevitable since AArch32 uses opc and AArch64 uses op.
>> + } else {
>> + *key = ENCODE_CP_REG(r->cp, is64, r->crn, crm, opc1, opc2);
>> + }
>
> Why the mutual exclusivity between 32 and 64 bit defs? Shouldn't it be
> possible to define with one ARMCPRegInfo a register that exists in
> both 32 and 64 and this code can just double add it to the hash table?
> May need two flags to describe existence in either or both schemes
> accordingly.
Almost all the shared registers appear as 32 bit on the AArch32
side and 64 bits on the AArch64 side. This means the required
fieldoffset value is different [or potentially so for bigendian hosts].
So you'd only be able to share registers which were genuinely
64 bit on both sides, which are very rare. So it didn't seem worth
trying to accommodate it.
-- PMM
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