6.S081 / Fall 2020 privileged instructions 着重介绍一些常见的特殊寄存器 mstatus / sstatus / ustatus 在中断使能方面,MIE、SIE、UIE分别提供了 machine mode 、supervisor mode 、user mode 的全局中断使能位,若一个 hart 运行在特权级别x下,当xIE = 1时中断全局打开,反之则关闭。在 hart 于x运行时,无论...
RISC-V 的官方标准主要分成两部分:用户指令集(User-Level Instruction Set Architecture)与特权架构(Privileged Architecture)。 RISC-V 用户指令分类如图 3-3 所示,RISC-V 的用户指令集分为基础整数指令 集(Base Integer Instruction Set)和扩展指令集(Extension)。根据处理器字长的 不同,基础整数指令集又有 32 位...
RISC-V基础指令集(RV32I与RV32E) RISC-V 的官方标准主要分成两部分:用户指令集(User-Level Instruction Set Architecture)与特权架构(Privileged Architecture)。 RISC-V 用户指令分类如图 3-3 所示,RISC-V 的用户指令集分为基础整数指令 集(Base Integer Instruction Set)和扩展指令集(Extension)。根据处理器字长...
其次，RISC-V的设计原则，也符合我们所谓的“大道至简”：RISC-V本身设计也相当简洁，只需要较少指令就能在硬体上执行；这样的好处是，CPU设计更容易，也较不占空间，执行速度也可以更快。目前的“RISC-V架构文档”分为“指令集文档”（riscv-spec-v2.2.pdf）和“特权架构文档”（riscv-privileged-v1.10.pdf...
This document describes the RISC-V privileged architecture,which covers all aspects of RISC-V systems beyond the user-level ISA, including privileged instructions as well as additional function-ality required for running operating systems and attaching external devices. Commentary on our design decisions...
Privileged InstructionsLink to heading In ourIntroduction to Instruction Formatspost we covered a few instructions offered by the RISC-V base ISAs, and touched briefly on how RISC-V uses an extension model to optionally add instructions and capabilities to a system. As part of the base ISAs, tw...
Implemented privileged instructions diagram as a bytefield-svg diagram. 1 parent cc578b7 commit b0671ec File tree src hypervisor.adoc images/bytefield priv-instr-set.edn machine.adoc priv-insns.adoc 4 files changed +237 -99lines changed src/hypervisor.adoc +1-1 Original file line number...
Additionally, RISC-V includes a separate privileged instruction set specification. These privileged instructions are supported. Pre-built runtime libraries are provided for compatibility with all of these configurations. RISC-V Custom Instructions
First of all, we added the logic required to store the current operating mode and switch between modes. This includes correct handling of exceptions and continuing execution after returning from executed subroutines. Since some RISC-V instructions are privileged and can only be executed from Machine...
The RISC-V privileged architecture covers all aspects of RISC-V systems beyond the unprivileged ISA, including privileged instructions as well as additional functionality required for running operating systems and attaching external devices. Each privilege level has a core set of privileged ISA extensions...