when abreakpoint(3), address-misaligned(0), access-fault(1、5、7), or page-fault(12、13、15) exceptionoccurs on an instruction fetch, load, or store, then stval will containthe faulting virtual address when amisaligned load or store(4、6)causes an access-fault or page-fault exception,...
04Load address misaligned 05Load access fault 06Store/AMO address misaligned 07Store/AMO access ...
虽然从技术角度来说,这两种存放方式各有利弊,但是考虑到目前大部分的 商用系统都采用小端模式,所以 RISC-V 的设计者也决定将小端模式定为 RISC-V 的标准模式。 2. 载入指令 和传统的 RISC 指令集一样,RISC-V 避免了 CISC 指令集中那种通过多种寻址方式 访问内存的做法,而将内存的访问仅限于载入(Load)和存储...
Note that there are scenarios where a misaligned load or store will generate an access exception instead of an address-misaligned exception. The access exception is raised when the misaligned access should not be emulated in a trap handler, e.g., emulating an access in an I/O region, as su...
③RAS(Return Address Stack,返回地址栈 ),RAS 与 BTB 有些类似, RAS主要是用来对跳转返回指令提供预测地址。当程序遇到函数调用指令时, 会把函数的返回地址存入 (push) 到 RAS 中。当取指器认为当前指令是一条跳 转返回指令时,就会做退栈动作 (pop),并把之前存在 RAS 栈顶的地址作为 下一条指令的读取地址...
00Instruction address misaligned 01Instructionaccess fault 02Illegal instruction 03Breakpoint 04Load address misaligned 05Load access fault 06Store/AMO address misaligned 07Store/AMO access fault 08Environment call from U-mode 09Environment call from S-mode ...
04Load address misaligned 05Load access fault 06Store/AMO address misaligned 07Store/AMO access ...
3 断点(Breakpoint) 同步 RISC-V架构定义了EBREAK指令,当处理器执行到该指令时,会发生异常进入异常服务程序。该指令往往用于调试器(Debugger)使用,譬如设置断点 4 读存储器地址非对齐(Load address misaligned) 同步 Load指令访存地址非对齐。 注意:N级别处理器内核支持可配置的地址非对齐的数据存储器读写操作,如果...
No region supports unaligned accesses. An unaligned access will generate the appropriate trap: instruction address misaligned, load address misaligned, or store/AMO address misaligned. 没有任何区域支持非对齐访问。非对齐访问会触发相应的陷阱:指令地址不对齐、加载地址不对齐或存储/原子操作(AMO)地址不对齐。
0 4 Load address misaligned 0 5 Load access fault 0 6 Store/AMO address misaligned 0 7 Store/AMO access fault 0 8 Environment call from U-mode 0 9 Environment call from S-mode 0 10 保留 0 11 Environment call from M-mode 0 12 Instruction page fault 0 13 Load page fault 0 14 保留...