【RISC-V设计-14】- RISC-V处理器设计K0A之打印输出

【RISC-V设计-14】- RISC-V处理器设计K0A之打印输出

1.简介

本文将详细阐述如何利用 printf 来打印字符串，在此过程中使用了一个开源的库 xprintf 。xprintf 是一个紧凑的字符串 I/O 库，它非常适用于程序存储器不足以用于常规 printf 函数的微型微控制器。通过调用 xprintf 函数成功输出了“Hello RISC-V World!”，同时还对该库的使用方法以及如何进行编译等内容加以介绍。xprintf库的地址为：http://elm-chan.org/fsw/strf/xprintf.html，下载后使将使用xprintf.c和xprintf.h两个文件。

2.验证用例

// -------------------------------------------------------------------------------------------------
// Copyright 2024 Kearn Chen, kearn.chen@aliyun.com
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// 
//     http://www.apache.org/licenses/LICENSE-2.0
// 
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// -------------------------------------------------------------------------------------------------
// Description :
//             1. Run Hello World!
// -------------------------------------------------------------------------------------------------

task initcase;

    load_instr("hello_world_test/hello_world_test.bin");

endtask

task testcase;

    #2_000_000;

endtask

在验证用例中，任务initcase加载Bin文件到仿真模型中，任务testcase延迟2毫秒，等待CPU执行完软件指令。

3.软件代码

// -------------------------------------------------------------------------------------------------
// Copyright 2024 Kearn Chen, kearn.chen@aliyun.com
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// 
//     http://www.apache.org/licenses/LICENSE-2.0
// 
// Unless required by applicable law or agreed to in writing, software
// distr