# OHVM **Repository Path**: wwhai/OHVM ## Basic Information - **Project Name**: OHVM - **Description**: No description available - **Primary Language**: Unknown - **License**: Apache-2.0 - **Default Branch**: master - **Homepage**: None - **GVP Project**: No ## Statistics - **Stars**: 0 - **Forks**: 0 - **Created**: 2021-09-21 - **Last Updated**: 2021-09-21 ## Categories & Tags **Categories**: Uncategorized **Tags**: None ## README # OHVM 虚拟机设计规范 ## 简介 这是我为了学习虚拟机原理和计算机程序运行原理，写的一个很简单的虚拟机demo，可以运行简单的字节码，当然如果我有时间和精力写出来相对完整点的版本，说不定还能搞个小玩具。 > OHVM 的含义是 "Only for Happy VM"，就是作者纯粹没有任何其他目的为了开心的产物。该设计本质是为了学习计算机技术，其没有任何生产和使用价值。 ## 基础规范 ### 内存范围 默认内存设定大小为 0-4KB，可以调整参数来扩大。 ### 寄存器分布 一共有 293 个个寄存器. ### 栈 一共有8层栈空间，每一层有32个寄存器。 ## 虚拟机模型 ![](res/model.png) ### 内存分布 1. 程序地址： 程序从 0x0000H 开始。 2. 入口地址： 程序入口地址默认是 0x0000H。 ##### 注意 > **_0x0H_** 是一个绝对地址, 真实地址是：**_1025_**. ### 寄存器分布 Those address can't be accessed by user program. | Name | Symbol | Size | Address(Decimal) | | -------------------- | --------- | ---------- | ---------------- | | NullPtr Register | NULL | 1byte | ROM: 0 - 1 | | VM Flag Register | FLAG | 1byte | ROM: 1 - 2 | | Addressing Register | A | 4byte | ROM: 3 - 5 | | ACCumulator | ACC | 4byte | ROM: 6 - 9 | | Program counter | PC | 4byte | ROM: 10 - 13 | | Stack index pointer | SP | 4byte | ROM: 14 - 17 | | Stack deepth pointer | SD | 4byte | ROM: 18 - 21 | | Exception Register | EXCPT | 4byte | ROM: 22 - 25 | | General Register | R{0...31} | 4byte(per) | ROM: 25 - 152 | | Stack Register | S{0...7} | 4byte(per) | ROM: 153 - 378 | ### 标志位寄存器 | Name | Symbol | Size | | --------- | ------ | ---- | | Zero | ZE | 1bit | | Equal | EQ | 1bit | | Execption | EX | 1bit | | Reserved | -- | 1bit | | Reserved | -- | 1bit | | Reserved | -- | 1bit | | Reserved | -- | 1bit | | Reserved | -- | 1bit | ## 指令集 | Instruction Code | Symbol | Example | Function | | ---------------- | --------------------- | ------------------------------------- | ---------------------------------------------------- | | 0X0000 | NOP | NOP | No operation, used for delay | | 0X0001 | START | START | Start ohvm | | 0X0002 | STOP | STOP | Stop ohvm | | 0X0003 | RSTR | RSTR | Reset all Register | | 0X0004 | TIMER [Rn] | MOVR R0 #5
TIMER R0 | Start Timer | | 0X0005 | GOTO [Rn]/[Label] | GOTO LOOP
GOTO R0 | GOTO ADDress | | 0X0006 | CALL [Rn]/[Label] | CALL LOOP
CALL R0 | CALL SUB process | | 0X0007 | BACK | BACK | RETURN from SUB process | | 0X0008 | JMP [Rn]/[Label] | JMP LOOP | JUMP Address With No Condition | | 0X0009 | JZ [ACC] [Rn]/[Label] | JZ LOOP | Compare with ACC, Jump Address if Zero Flag == 1 | | 0X000A | JE [ACC] [Rn]/[Label] | JE LOOP | Compare with ACC, Jump Address if Equal Flag == 1 | | 0X000B | JX [ACC] [Rn]/[Label] | JX LOOP | Compare with ACC, Jump Address if Excepion Flag == 1 | | 0X000C | CMRAE [Rn] | MOV R0 #1
CMRAE | COMPARE R{x} if equal ACC | | 0X000D | CMRAG [Rn] | MOV R0 #1
CMRAG | COMPARE R{x} if greater than ACC | | 0X000E | CMRAL [Rn] | MOV R0 #1
CMRAL | COMPARE R{x} if little than ACC | | 0X000F | CMRRE [Rn] [Rn] | MOV R0 #1
MOV R1 #1
CMRRE R0 R1 | COMPARE R{x} if equal R{x} | | 0X0010 | CMRRG [Rn] [Rn] | MOV R0 #1
MOV R1 #1
CMRRG R0 R1 | COMPARE R{x} if greater than R{x} | | 0X0011 | CMRRL [Rn] [Rn] | MOV R0 #1
MOV R1 #1
CMRRL R0 R1 | COMPARE R{x} if little than R{x} | | 0X0012 | CMASE [Rn] [Sn] | CMASE R0 S0 | COMPARE ACC if equal than Stack | | 0X0013 | CMASG [Rn] [Sn] | CMASG R0 S0 | COMPARE ACC if greater than Stack | | 0X0014 | CMASL [Rn] [Sn] | CMASL R0 S0 | COMPARE ACC if little than Stack | | 0X0015 | CMRSE [Rn] [Sn] | CMRSE R0 S0 | COMPARE R{x} if little than Stack | | 0X0016 | CMRSG [Rn] [Sn] | CMRSG R0 S0 | COMPARE R{x} if greater than Stack | | 0X0017 | CMRSL [Rn] [Sn] | CMRSL R0 S0 | COMPARE R{x} if little than Stack | | 0X0018 | INCA | INCA | INCREASE ACC | | 0X0019 | DECA | DECA | DECREASE ACC | | 0X001A | INCR [Rn] | INCR R0 | INCREASE Register{x} | | 0X001B | DECR [Rn] | DECR R0 | DECREASE Register{x} | | 0X001C | ADDAR [Rn] | MOV R0 #1
ADDAR R0 | ADD ACC and Register{x} | | 0X001D | SUBAR [Rn] | MOV R0 #1
SUBAR R0 | SUB ACC and Register{x} | | 0X001E | INCS | INCS | INCREASE Stack | | 0X001F | DECS | DECS | DECREASE Stack | | 0X0020 | ADDAS [Sn] | ADDAS S0 | ADD ACC and Stack | | 0X0021 | SUBAS [Sn] | SUBAS S0 | SUB ACC and Stack | | 0X0022 | ANDR [Rn] | MOV R0 #1
ANDR R0 | ACC AND Register{x} | | 0X0023 | AOR [Rn] | MOV R0 #1
AOR R0 | ACC OR Register{x} | | 0X0024 | AXR [Rn] | MOV R0 #1
AXR R0 | ACC XOR Register{x} | | 0X0025 | BSLR [Rn] | MOV R0 #1
BSLR R0 | BIT Shift left in Register{x} | | 0X0026 | BSRR [Rn] | MOV R0 #1
BSRR R0 | BIT Shift right in Register{x} | | 0X0027 | BSLLR [Rn] | MOV R0 #1
BSLLR R0 | BIT Shift left loop in Register{x} | | 0X0028 | BSRLR [Rn] | MOV R0 #1
BSRLR R0 | BIT Shift right loop in Register{x} | | 0X0029 | ANDS [Sn] | ANDS S0 | ACC AND Stack | | 0X002A | AOS [Sn] | AOS S0 | ACC OR Stack | | 0X002B | AXS [Sn] | AXS S0 | ACC XOR Stack | | 0X002C | BSLS [Sn] | BSLS S0 | BIT Shift left in Stack | | 0X002D | BSRS [Sn] | BSRS S0 | BIT Shift right in Stack | | 0X002E | BSLLS [Sn] | BSLLS S0 | BIT Shift left loop in Stack | | 0X002F | BSRLS [Sn] | BSRLS S0 | BIT Shift right loop in Stack | | 0X0030 | IMA #[Hex] | IMA #1 | Immediately value to ACC | | 0X0031 | IMR [Rn] #[Hex] | IMR R0 #1 | Immediately value to Register | | 0X0032 | IMS [Sn] #[Hex] | IMS S1 #1 | Immediately value to Stack | | 0X0033 | GET [Rn] | GET R1 | Get value from address | | 0X0034 | MVRR [Rn] [Rn] | MVRR R0 R0 | MOVE Register value to another Register{x} | | 0X0035 | MVRS [Rn] [Sn] | MVRS R0 S0 | MOVE Register value to Stack | | 0X0036 | MVSR [Rn] [Rn] | MVRS S0 R0 | MOVE Stack value to Register | | 0X0037 | MVAR [Rn] | MVAR R0 | MOVE ACC value to Register | | 0X0038 | INTK | INTK | Wait key interupt | | 0X0039 | KEY | KEY | Get key | | 0X003A | PLY [Rn] | MOV R0 #1
PLY R0 | Play dididi sound | | 0X003B | PLYS [Rn] | MOV R0 #1
PLYS R0 | Play a series of sound.Usually have a frequence | | 0X003C | GSET [Rn] | MOV R0 #1
GSET R0 | Graphics resolution setting, [64X32 - 640X320] | | 0X003D | CLS | CLS | Clear screen | | 0X003E | DPXY [Rn] | MOV R0 #1
DPXY R0 | Draw 8 \* x pixels at (x, y) | | 0X003F | DXY [Rn] | MOV R0 #1
DXY R0 | Draw point at (x, y) | | 0X0040 | DCXY [Rn] | MOV R0 #1
DCXY R0 | Draw char at (x, y) | | 0X0041 | DLINE [Rn] | MOV R0 #1
DCXY R0 | Draw line | | 0X0042 | DRECT [Rn] | MOV R0 #1
DCXY R0 | Draw rectangle | | 0X0043 | SCRU | SCRU | Screen scrool up x pixel | | 0X0044 | SCRD | SCRD | Screen scrool down x pixel | | 0X0045 | SCRL | SCRL | Screen scrool left x pixel | | 0X0046 | SCRR | SCRR | Screen scrool right x pixel | | 0X0047 | SET [Rn] | SET R0 | Set value to ram | ## 汇编规范 ### 关键字 - **_MAIN_**: 入口标识符 - **_STOP_**: 直接退出虚拟机 - **_BEGIN_**: 子程序声明标识符 - **_END_**: 子程序标签 ##### _注意:_ >
关键字不可用于其他地方!
### 汇编格式 1. 入口 用 `MAIN` 标记入口，一个程序必须有一个 `MAIN`。 2. 子程序 用 `BEGIN {子程序名}: [statement] END` 来声明一个子程序，例如声明一个输出字符的子程序： ```assembly BEGIN OUTPUT_CHAR: ;; END ``` 3. 退出 退出用 `STOP` 标签标记，程序只要到 `STOP`，立即结束所有运行。 ```assembly STOP ``` 4. 注释 使用双分号注释: `;;` ``` ;;这是一行注释 ``` ## 汇编案例 ```assembly ;; Example program ;; main MAIN: IA 0 ;; ACC = 0 IR R0 #1 ;; R0 = 1 ADDAR R0 ;; ACC = ACC + R0 CALL DISPLAY ;; Call display STOP ;; END ;; display sub process BEGIN DISPLAY: DCXY 40, 50, ACC ;; Display value in ACC END ``` ## 异常处理 按理来说汇编不应该有异常处理这种设计的，但是我想了下异常处理的本质也是一个 `JMP`,于是我自作聪明的设计了这个语法：`TRY ... CATCH`. ``` TRY ;; .... ;; .... ;; .... CATCH ${Address} ``` 捕获异常时，将设置 `EX` 寄存器设置为1，并且跳转到 `CATCH` 指定的代码位置处。 ## 字节码规范 如图： ![](res/bc-format.png) ## OHVM Lang 假设已经设计好了一个高级语言叫:OHVM Lang: [OHVM Lang](./ohvmlang/readme.md)。 ## 编译器 我现在技术不到家，写不出来高级语言编译器，本来打算设计一个简单的编译器，把 C 或者是 BASIC 这种基础语法编译成字节码，但是我水平太菜了，搞不定，于是这里只能手动来写字节码了。 ### 如何编译 编译流程： ``` ┌───────────────────────┐ │ BASIC Source code │ │ │ └──────────┬────────────┘ │ ▼ ┌───────────────────────┐ │ OHVM ASM code │ │ │ └──────────┬────────────┘ │ ┌──────────▼────────────┐ │ │ │ OHVM Byte code │ └───────────────────────┘ ``` 假设编译器已经实现好了，应该按照下面的方式来使用： ```shell # 要编译这个文件：hello_world.oohvms oohvmcc hello_world.oohvms # 编译完成后，应该有下面这几个文件： # hello_world.oohvmasm hello_world.oohvmbc ``` > oohvms 为源代码文件；oohvmasm 为汇编代码；oohvmbc 为字节码文件 ## 任务规划 - [x] 基础指令集设计 - [ ] 项目结构设计 - [ ] 虚拟机内核设计 - [ ] 汇编器设计 - [ ] 高级程序语言设计 - [ ] 程序编译器设计 ## 资源链接 - Blog: https://openlab.ezlinker.cn - Mail: cnwwhai@gmail.com ## 参考 - 《计算机程序运行原理》 - 《C语言核心技术》 - 《Linux内核开发》 - YACC，LEX 等基础官方文档（实现编译器相关）