Hi Bin, On Fri, May 24, 2019 at 05:40:08PM +0800, Bin Meng wrote:
Hi Eric,
On Fri, May 24, 2019 at 4:04 PM Eric Lin dslin1010@gmail.com wrote:
Hi Bin
Bin Meng bmeng.cn@gmail.com ??? 2019???5???22??? ?????? ??????5:25?????????
Hi Eric,
On Wed, May 22, 2019 at 4:23 PM tesheng@andestech.com wrote:
Hi Bin,
-----Original Message----- From: Bin Meng [mailto:bmeng.cn@gmail.com] Sent: Tuesday, May 21, 2019 3:56 PM To: Eric Te-Sheng Lin(?????????) Cc: U-Boot Mailing List; Lukas Auer; Anup Patel; Rick Jian-Zhi Chen(?????????); Greentime Ying-Han Hu(?????????); dslin1010@gmail.com Subject: Re: [PATCH] riscv: add Kconfig entries for the F and D ISA extensions support
Hi Eric,
On Tue, May 21, 2019 at 3:18 PM Eric Lin tesheng@andestech.com wrote:
This patch add Kconfig entries for the F (Single-Precision)
adds
OK I'll correct it as adds
and D (Double-Precision) floating point instruction-set extensions.
Could you please provide reason that why U-Boot has to be compiled using F/D extension?
Cause on AE350 platform, we have two different kinds of toolchain v5d (support I/M/A/C/F/D ISA) and v5 (support I/M/A/C ISA). If we use the v5d toolchain to build U-Boot it will build fail, so we would like to add F/D extension on U-Boot.
I don't understand. What difference do these two toochains have? Isn't the v5d toolchain's default -march string be pre-configured to imafd? But even if the toolchain is pre-configured to generate fd instruction, I think it can be override by the compiler flags. Can you please share the details of the toolchain you used? I suspect you have to fix your toolchain, not U-Boot.
It's seems the ABI issue. Because our toolchain don't support multilib, the v5d toolchain libraries ABI is ilp64d. If I use the v5d toolchain to build U-Boot with -mabi=lp64, it will get link error as below:
Then please fix your compiler. Passing -mabi=lp64 to compiler is definitely correct.
One of our customer ever used floating point in their project. They want to calculate something with floating point instructions in u-Boot before entering kernel.
IMHO, we may consider this case for user to use -mabi=ilp64d. This CONFIG will be useful for them to compile their codes and linking together with u-Boot.
Thanks :)