On 2020/8/6 14:09, Chih-Min Chao wrote:
On Fri, Jul 24, 2020 at 2:06 PM LIU Zhiwei <zhiwei_...@c-sky.com
<mailto:zhiwei_...@c-sky.com>> wrote:
On 2020/7/24 11:55, Richard Henderson wrote:
> On 7/23/20 7:35 PM, LIU Zhiwei wrote:
>>
>> On 2020/7/24 8:28, Richard Henderson wrote:
>>> Make sure that all results from single-precision scalar helpers
>>> are properly nan-boxed to 64-bits.
>>>
>>> Signed-off-by: Richard Henderson <richard.hender...@linaro.org
<mailto:richard.hender...@linaro.org>>
>>> ---
>>> target/riscv/internals.h | 5 +++++
>>> target/riscv/fpu_helper.c | 42
+++++++++++++++++++++------------------
>>> 2 files changed, 28 insertions(+), 19 deletions(-)
>>>
>>> diff --git a/target/riscv/internals.h b/target/riscv/internals.h
>>> index 37d33820ad..9f4ba7d617 100644
>>> --- a/target/riscv/internals.h
>>> +++ b/target/riscv/internals.h
>>> @@ -38,4 +38,9 @@ target_ulong fclass_d(uint64_t frs1);
>>> #define SEW32 2
>>> #define SEW64 3
>>> +static inline uint64_t nanbox_s(float32 f)
>>> +{
>>> + return f | MAKE_64BIT_MASK(32, 32);
>>> +}
>>> +
>> If define it here, we can also define a more general function
with flen.
>>
>> +static inline uint64_t nanbox_s(float32 f, uint32_t flen)
>> +{
>> + return f | MAKE_64BIT_MASK(flen, 64 - flen);
>> +}
>> +
>>
>> So we can reuse it in fp16 or bf16 scalar instruction and in
vector instructions.
> While we could do that, we will not encounter all possible
lengths. In the
> cover letter, I mentioned defining a second function,
>
> static inline uint64_t nanbox_h(float16 f)
> {
> return f | MAKE_64BIT_MASK(16, 48);
> }
>
> Having two separate functions will, I believe, be easier to use
in practice.
>
Get it. Thanks.
Zhiwei
>
> r~
That is what has been implemented in spike. It fills up the Nan-Box
when value is stored back internal structure and
unbox the value with difference floating type (half/single/double/quad).
Hi Chih-Min,
Has half-precision been a part of RVV? Or do you know the ISA
abbreviation of half-precision?
Thanks very much.
Best Regards,
Zhiwei
By the way, I prefer to keeping the suffix to tell different floating
type rather than pass arbitrary
since each floating type belong to each extension.
Reviewed-by: Chih-Min Chao <chihmin.c...@sifive.com
<mailto:chihmin.c...@sifive.com>>
