[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [PATCH v2 1/7] target/riscv: Generate nanboxed results from fp helpe

From: LIU Zhiwei
Subject: Re: [PATCH v2 1/7] target/riscv: Generate nanboxed results from fp helpers
Date: Fri, 24 Jul 2020 14:05:34 +0800
User-agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0

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.henderson@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 
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.



reply via email to

[Prev in Thread] Current Thread [Next in Thread]