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一、说明

本文根据以下文章改编：

• RISC-V 环境配置
  https://decaf-lang.github.io/minidecaf-tutorial/docs/step0/riscv_env.html

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相关链接：

• riscv-gnu-toolchain
  GNU toolchain for RISC-V, including GCC
  https://github.com/riscv/riscv-gnu-toolchain
• brew - Custom-GCC-and-cross-compilers
  https://docs.brew.sh/Custom-GCC-and-cross-compilers
• riscv-isa-sim
  Spike, a RISC-V ISA Simulator
  https://github.com/riscv-software-src/riscv-isa-sim
• riscv-pk
  RISC-V Proxy Kernel
  https://github.com/riscv-software-src/riscv-pk

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二、安装步骤

1、使用 brew 安装相关依赖

brew install dtc gawk gnu-sed gmp mpfr libmpc isl zlib expat texinfo flockbrew tap riscv/riscv
brew install riscv-tools  
brew install riscv-isa-sim  
brew install qemu

brew 安装的文件包一般位于：/usr/local/Cellar 下

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2、下载预编译好的 RISC-V 工具链
riscv64-unknown-elf-gcc-8.3.0-2020.04.0-x86_64-apple-darwin.tar.gz
https://static.dev.sifive.com/dev-tools/riscv64-unknown-elf-gcc-8.3.0-2020.04.0-x86_64-apple-darwin.tar.gz

解压后，将 bin 目录添加到环境变量

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可以得到如下的可执行文件等：

riscv64-unknown-elf-addr2line

• riscv64-unknown-elf-gcc-ar
• riscv64-unknown-elf-ld.bfd
• riscv64-unknown-elf-ar
• riscv64-unknown-elf-gcc-nm
• riscv64-unknown-elf-nm
• riscv64-unknown-elf-as
• riscv64-unknown-elf-gcc-ranlib
• riscv64-unknown-elf-objcopy
• riscv64-unknown-elf-c++
• riscv64-unknown-elf-gcov
• riscv64-unknown-elf-objdump
• riscv64-unknown-elf-c++filt
• riscv64-unknown-elf-gcov-dump
• riscv64-unknown-elf-ranlib
• riscv64-unknown-elf-cpp
• riscv64-unknown-elf-gcov-tool
• riscv64-unknown-elf-readelf
• riscv64-unknown-elf-elfedit
• riscv64-unknown-elf-gdb
• riscv64-unknown-elf-size
• riscv64-unknown-elf-g++
• riscv64-unknown-elf-gdb-add-index
• riscv64-unknown-elf-strings
• riscv64-unknown-elf-gcc
• riscv64-unknown-elf-gprof
• riscv64-unknown-elf-strip
• riscv64-unknown-elf-gcc-8.3.0
• riscv64-unknown-elf-ld

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3、下载 spike 预编译的二进制程序包

spike-pk-prebuilt-x86_64-apple-darwin.tar.gz
https://cloud.tsinghua.edu.cn/f/6246e90c407b4a508816/

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解压后，制作 pk 软连接

ln xxx/software/spike-pk-prebuilt-x86_64-apple-darwin/pk  /usr/local/bin/pk

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否则执行程序可能报错：

libc++abi: terminating due to uncaught exception of type std::runtime_error: could not open /usr/local/bin/pk (did you misspell it? If VCS, did you forget +permissive/+permissive-off?)

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三、测试

实现如下功能：

• 生成 RISC-V 汇编
• 使用 gcc 把 RISC-V 汇编变成 RISC-V 可执行文件
• 用 spike 运行 RISC-V 可执行文件。

                  你的编译器                gcc            qemu/spike
MiniDecaf 源文件 ------------> RISC-V 汇编 -----> 可执行文件 --------> 输出

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1、编写文件 input.c

int main(){return 233;}

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2、编译到 input.s

riscv64-unknown-elf-gcc -march=rv32im -mabi=ilp32 -O3 -S input.c

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得到 cat input.s，你可以查看它的内容

cat input.s

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得到：

	.file	"input.c".option nopic.attribute arch, "rv32i2p1_m2p0".attribute unaligned_access, 0.attribute stack_align, 16.text.section	.text.startup,"ax",@progbits.align	2.globl	main.type	main, @function
main:li	a0,122ret.size	main, .-main.ident	"GCC: (g2ee5e430018-dirty) 12.2.0"

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3、编译成可执行文件

riscv64-unknown-elf-gcc -march=rv32im -mabi=ilp32 input.s

生成 a.out 文件

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你也可以跳过 -s 直接生成可执行文件

riscv64-unknown-elf-gcc -march=rv32im -mabi=ilp32 -O3 test.c

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查看 a.out 文件属性

file a.out

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得到：

a.out: ELF 32-bit LSB executable, UCB RISC-V, soft-float ABI, version 1 (SYSV), statically linked, not stripped

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4、执行 a.out

spike --isa=RV32G /usr/local/bin/pk a.out

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打印出

bbl loader

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继续执行
打印 $?，这是 spike 的返回码，也就是我们 .c 文件 main 方法返回的值

echo $?

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伊织 2023-08-21