https://github.com/hczhcz/y86

Yet another Y86 implementation
https://github.com/hczhcz/y86

Last synced: 8 days ago
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Yet another Y86 implementation

• Host: GitHub
• URL: https://github.com/hczhcz/y86
• Owner: hczhcz
• Created: 2014-05-12T05:42:09.000Z (over 10 years ago)
• Default Branch: master
• Last Pushed: 2018-06-10T17:38:47.000Z (over 6 years ago)
• Last Synced: 2024-08-01T21:42:35.221Z (4 months ago)
• Language: C
• Size: 69.3 KB
• Stars: 67
• Watchers: 4
• Forks: 12
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

Awesome Lists containing this project

• awesome-se - hczhcz-2013: y86jit

README

        
Yet another Y86 implementation

===

About Y86

---

Y86 is a simplified x86-like instruction set.

8 user-accessible registers:

`EAX ECX EDX EBX ESP EBP ESI EDI`

4 states:

`AOK HLT ADR INS`

Instructions:

`halt nop rr/cmovXX irmovl rmmovl mrmovl OPTl jXX call ret pushl popl`

ASM file example:

    # Execution begins at address 0

           .pos 0

    init:  irmovl Stack, %esp       # Set up stack pointer

           irmovl Stack, %ebp       # Set up base pointer

           call Main                # Execute main program

           halt                     # Terminate program

    # Array of 4 elements

           .align 4

    array: .long 0xd

           .long 0xc0

           .long 0xb00

           .long 0xa000

    Main:  pushl %ebp

           rrmovl %esp,%ebp

           irmovl $4,%eax

           pushl %eax               # Push 4

           irmovl array,%edx

           pushl %edx               # Push array

           call Sum                 # Sum(array, 4)

           rrmovl %ebp,%esp

           popl %ebp

           ret

    #/* $begin sum-ys 0 */

    # int Sum(int *Start, int Count)

    Sum:   pushl %ebp

           rrmovl %esp,%ebp

           mrmovl 8(%ebp),%ecx      # ecx = Start

           mrmovl 12(%ebp),%edx     # edx = Count

           xorl %eax,%eax           # sum = 0

           andl %edx,%edx           # Set condition codes

           je End

    Loop:  mrmovl (%ecx),%esi       # get *Start

           addl %esi,%eax           # add to sum

           irmovl $4,%ebx

           addl %ebx,%ecx           # Start++

           irmovl $-1,%ebx

           addl %ebx,%edx           # Count--

           jne Loop                 # Stop when 0

    End:   rrmovl %ebp,%esp

           popl %ebp

           ret

    #/* $end sum-ys 0 */

    # The stack starts here and grows to lower addresses

           .pos 0x100

    Stack:

For more details: Chapter 4 of [CSAPP](http://csapp.cs.cmu.edu/)

Y86 Simulator

---

This is a 'lab' (homework) in SE101/ICS (Introduction to Computer Systems).

The original version is a 'pure' simulator, but I made a JIT compiler.

Build:

`cc -m32 -o y86sim y86sim.c` (tested under Clang 3.2+)

Run:

`y86sim file.bin [max_steps]`

Y86 Simulator (the 'max' version)

---

The 'max' version looks like the normal one, but there is no step counting and non-static error detecting in it.

It could execute most cases correctly and run (almost) as fast as native x86. But, it could not pass the ICS lab tests.

Y86 Assembler

---

This is also a 'lab' in SE101/ICS.

The implementation is based on the original framework in the course.

Build:

`cc -m32 -o y86asm y86asm.c` (tested under Clang 3.2+)

Run:

`y86asm [-v] file.ys`

`-v` print the readable output to screen.

License

---

The simulator is released under WTFPL. Keep calm and have fun with it :) Feel free to send issues and PR to me.

The assembler and the lab tests are not released under any license, so they can be used in education purpose only.

To SE101 students: DO NOT CHEAT! The code is stored in the anti-cheating code base. You know.