jserv / full-stack-hello Goto Github PK

@jserv maybe is time to open ci for build status and PR build check.

At the moment, DIV and MOD considers divide-by-zero (I'll call it as DBZ from now on) as unimplemented.

We are in need of an exception handling mechanism when DBZ happens.

I can think of a few ways now:

1. Add a (typical) exception handling callback (like ISR) like general CPUs do.
2. Add a global flag that can be set when DBZ happens and code can explicitly check the flag after a DIV or MOD operation is performed.

The considerations that I can think of by now. They are tradeoffs during most of the time.

A. Speed
B. VM Complexity
C. Support of higher level semantics, such as C++ Exception

Current design about opcode implement hook is to hook the corresponding implement to each instruction in env->insts, which the insts is read from file.

Should it be hook on an opcode impl list, then each instruction only need to call from env->impl[opcode](...), this should be more efficient for memory usage and hooking stage.

Maybe somehow we can generate bytecode, and run from bytecode? without assemble_from_file.

Recently, @pakls contributed a series of conditional branch instructions which enables further translation from higher level languages to our virtual machine. However, lacking of labels prevents jump instructions from being efficiently used.

Thus, we expect that assembler can recognize labels as the indicators of open/close loop or deterministic location.

Need SHIFT, OR, XOR, NOT support to do useful logical operations.

While executing test runner with Python2, I got the following error:

  File "tests/runner.py", line 38
    class TestRunner(unittest.TestCase, metaclass=TestRunnerMeta):
                                                 ^
SyntaxError: invalid syntax

Cc. @mlouielu

commit: 73432bf, can't pass the test suite:

FFF
======================================================================
FAIL: test_coverage (__main__.TestRunner)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "tests/runner.py", line 38, in test
    self.assertEqual(got, expected)
AssertionError: b'' != b'42\n50\n150\n'

======================================================================
FAIL: test_halt (__main__.TestRunner)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "tests/runner.py", line 38, in test
    self.assertEqual(got, expected)
AssertionError: b'' != b'42\n'

======================================================================
FAIL: test_hello (__main__.TestRunner)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "tests/runner.py", line 38, in test
    self.assertEqual(got, expected)
AssertionError: b'' != b'Hello\n'

----------------------------------------------------------------------
Ran 3 tests in 0.001s

FAILED (failures=3)
make: *** [Makefile:36: test] Error 1

If the format of an instruction takes two parameters, as_exec crashes if the code is written with only one operand.

I think this can be a goal for this VM, to make it a Turing complete VM (programmign language / instruction set ?)

Some reference:

• https://en.wikipedia.org/wiki/%CE%9C-recursive_function
• https://math.stackexchange.com/questions/112011/how-to-prove-a-programming-language-is-turing-complete

zizo noui

Got:

➜  full-stack-hello git:(master) ✗ make check 
tests/hello.s pass

tests/test.s pass

Expect:

➜  full-stack-hello git:(master) ✗ make check
Hello
tests/hello.s pass

42
50
150
tests/test.s pass

Hi, All, I am implementing the support of this. :)

Currently, the instruction set implementation is host specific. That is, if current host is 64 bits, then the in VM and everything will be 64 bits, and vice versa.

Should this instruction set be given a sound name?

https://www.wikiwand.com/en/List_of_instruction_sets

This is a naive idea at its infancy: Integrate this VM based code with native code.

Allowing them to invoke each other.

Some assumptions/limitations may have to be imposed to speed up the execution and data type conversion.

Need DIV and MOD instructions to do useful mathematics.

Currently, only ^Hello can be printed. Need to support space character, such as

'Hello World', or "Hello World"

to be a real 'Hello World' full-stack demo.

Hi @jserv @mlouielu,

Shall the instruction set to be expanded to support stack?