On 12/2/25 06:28, Icenowy Zheng wrote:
在 2025-12-02星期二的 03:57 +0000，Yao Zi写道：
On Mon, Dec 01, 2025 at 06:49:03PM +0100, Heinrich Schuchardt wrote:
The following functions are provided:
Count leading zero bits
* int __clzsi2 (unsigned int a)
* int __clzdi2 (unsigned long a)
* int __clzti2 (unsigned long long a)
Count trailing zero bits
* int __ctzsi2 (unsigned int a)
* int __ctzdi2 (unsigned long a)
* int __ctzti2 (unsigned long long a)
Signed-off-by: Heinrich Schuchardt
<[email protected]>
---
I noted there's another series with the same subject[1] sent almost
at
the same time, and I couldn't tell the difference at the first
glance.
Is this an incident?
arch/Kconfig | 1 +
arch/riscv/lib/Makefile | 2 +
arch/riscv/lib/clz.c | 105
++++++++++++++++++++++++++++++++++++++++
arch/riscv/lib/ctz.c | 95 ++++++++++++++++++++++++++++++++++++
lib/Kconfig | 2 +-
5 files changed, 204 insertions(+), 1 deletion(-)
create mode 100644 arch/riscv/lib/clz.c
create mode 100644 arch/riscv/lib/ctz.c
diff --git a/arch/Kconfig b/arch/Kconfig
index 3133f892f94..4af0da2485f 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -159,6 +159,7 @@ config PPC
config RISCV
bool "RISC-V architecture"
select CREATE_ARCH_SYMLINK
+ select HAVE_PRIVATE_LIBGCC if 64BIT
Are 32-bit platforms excluded for lacking of enough library
functions?
Yes. See
https://lore.kernel.org/u-boot/[email protected]/T/#mbf44c9f5073649bbf2e1368ffbeaec82680a268d
Should we exclude !RISCV_ISA_F || !RISCV_ISA_D platforms as well?
Though
libgcc.a as provided by distros assumes that you have the D and F
extensions. Either a specific libgcc.a will be needed or we will have to
implement the missing functions in the private lib if such platforms.
It would make more sense to set CONFIG_USE_PRIVATE_LIBGCC=n for such
platforms than setting CONFIG_HAVE_PRIVATE_LIBGCC=n.
Which way we want to go can be decided when such platforms arrive.
there's no in-tree 64-bit port without F/D extension.
The S7 core in U74-MC complex seems to have only IMAC, no F/D.
The S7 core is not supported by U-Boot.
Best regards
Heinrich
select HAVE_SETJMP
select HAVE_INITJMP
select SUPPORT_ACPI
Regards,
Yao Zi
[1]:
https://lore.kernel.org/u-boot/[email protected]/
