From 1c507a02f29c6ca735f40f4b16b341ce9d5aa1b1 Mon Sep 17 00:00:00 2001
From: Yangyu Chen <chenyangyu@isrc.iscas.ac.cn>
Date: Mon, 14 Oct 2024 18:31:06 +0800
Subject: [PATCH] RISC-V: Add detailed comments on processing implied
extensions. [NFC]
In some cases, we don't need to handle implied extensions. Add detailed
comments to help developers understand what implied ISAs should be
considered.
libgcc/ChangeLog:
* config/riscv/feature_bits.c (__init_riscv_features_bits_linux):
Add detailed comments on processing implied extensions.
Signed-off-by: Yangyu Chen <chenyangyu@isrc.iscas.ac.cn>
---
libgcc/config/riscv/feature_bits.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/libgcc/config/riscv/feature_bits.c b/libgcc/config/riscv/feature_bits.c
index 9bdbc466feea..a90e553b83d6 100644
--- a/libgcc/config/riscv/feature_bits.c
+++ b/libgcc/config/riscv/feature_bits.c
@@ -290,9 +290,12 @@ static void __init_riscv_features_bits_linux ()
}
const struct riscv_hwprobe hwprobe_ima_ext = hwprobes[4];
-
/* Every time we add new extensions, we should check if previous extensions
- imply the new extension and set the corresponding bit. */
+ imply the new extension and set the corresponding bit.
+ We don't need to handle cases where:
+ 1. The new extension implies a previous extension (e.g., Zve32f -> F).
+ 2. The extensions imply some other extensions appear in the same release
+ version of Linux Kernel (e.g., Zbc - > Zbkc). */
if (hwprobe_ima_ext.value & RISCV_HWPROBE_IMA_FD)
{
@@ -397,7 +400,7 @@ __init_riscv_feature_bits ()
#ifdef __linux
__init_riscv_features_bits_linux ();
#else
- /* Unsupported, just initlizaed that into all zeros. */
+ /* Unsupported, just initialize that into all zeros. */
__riscv_feature_bits.length = 0;
__riscv_vendor_feature_bits.length = 0;
__riscv_cpu_model.mvendorid = 0;
--
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