On 05/25/2011 08:56 AM, Hans-Peter Nilsson wrote:
> On Tue, 10 May 2011, Bernd Schmidt wrote:
>
>> I've found it useful to use a construct such as the following:
>>
>> (define_attr "units64"
>> "unknown,d,d_addr,l,m,s,dl,ds,dls,ls"
>> (const_string "unknown"))
>>
>> (define_attr "units64p"
>> "unknown,d,d_addr,l,m,s,dl,ds,dls,ls"
>> (attr "units64"))
>>
>> to define one attribute in terms of another by default,
>
> So it's just the units64p default value taken from the units64
> default value or units64p gets its default value from the final
> units64 value?
units64p has the final value of units64, unless an insn explicitly gives
it a different value. This is because C64X+ is really very similar to
C64X in most respects. We then select which of the various units
definitions to use for a given CPU:
(define_attr "units"
"unknown,d,d_addr,l,m,s,dl,ds,dls,ls"
(cond [(eq_attr "cpu" "c62x")
(attr "units62")
(eq_attr "cpu" "c67x")
(attr "units67")
(eq_attr "cpu" "c67xp")
(attr "units67p")
(eq_attr "cpu" "c64x")
(attr "units64")
(eq_attr "cpu" "c64xp")
(attr "units64p")
(eq_attr "cpu" "c674x")
(attr "units674")
]
(const_string "unknown")))
>> allowing
>> individual insn patterns to override the definition of "units64p" where
>> necessary. This patch adds support for this in genattrtab.
>
> I'm not sure I get it, and I think I would be helped by seeing
> the documentation update. ;)
I'm not sure where you're looking for added documentation for this
patch. It just generalizes the define_attr mechanism a little to allow
one more kind of expression.
Bernd
