PicoBlaze Simulator in JavaScript

[FlatAssembler]

@bennyboy , you say you are an experienced web developer. Could you please look into my PicoBlaze Simulator in JavaScript and tell me how I could speed it up? I cannot diagnose why it is so slow.

[BrianSoddingBoru4]

@bennyboy , you say you are an experienced web developer. Could you please look into my PicoBlaze Simulator in JavaScript and tell me how I could speed it up? I cannot diagnose why it is so slow.

Maybe you should either take some remedial courses or hire yourself a tutor.

Boru

[HappySkeptic]

@bennyboy , you say you are an experienced web developer. Could you please look into my PicoBlaze Simulator in JavaScript and tell me how I could speed it up? I cannot diagnose why it is so slow.

No-one is going to help you on such a generic question.  First, write a series of performance tests with timings.  Then, use the a performance tool on whatever Javascript system you are on (the one in Chrome are good).  Look for hot spots in the bottom-up profiling.

When coding for performance, I always have an idea of the performance I'm expecting.  I break down the pieces and check the speed of each.  If you aren't testing with actual numbers, you have nothing to go by.

[FlatAssembler]

@bennyboy , you say you are an experienced web developer. Could you please look into my PicoBlaze Simulator in JavaScript and tell me how I could speed it up? I cannot diagnose why it is so slow.

No-one is going to help you on such a generic question.  First, write a series of performance tests with timings.  Then, use the a performance tool on whatever Javascript system you are on (the one in Chrome are good).  Look for hot spots in the bottom-up profiling.

When coding for performance, I always have an idea of the performance I'm expecting.  I break down the pieces and check the speed of each.  If you aren't testing with actual numbers, you have nothing to go by.

Whence am I supposed to know all those things? I am just a third-year computer science student. And I have also been using a hell lots of things we haven't been taught at the university in my program.

[FlatAssembler]

@bennyboy , you say you are an experienced web developer. Could you please look into my PicoBlaze Simulator in JavaScript and tell me how I could speed it up? I cannot diagnose why it is so slow.

Maybe you should either take some remedial courses or hire yourself a tutor.

Boru

What are "remedial courses"? What's a "tutor"?

[BrianSoddingBoru4]

Maybe you should either take some remedial courses or hire yourself a tutor.

Boru

What are "remedial courses"? What's a "tutor"?

Remedial courses are ones you take to learn (or re-learn) the basics. A tutor is a private teacher.

Boru

[BrianSoddingBoru4]

No-one is going to help you on such a generic question.  First, write a series of performance tests with timings.  Then, use the a performance tool on whatever Javascript system you are on (the one in Chrome are good).  Look for hot spots in the bottom-up profiling.

When coding for performance, I always have an idea of the performance I'm expecting.  I break down the pieces and check the speed of each.  If you aren't testing with actual numbers, you have nothing to go by.

Whence am I supposed to know all those things? I am just a third-year computer science student. And I have also been using a hell lots of things we haven't been taught at the university in my program.

If you’ve been at this for three years and don’t understand performance tests, maybe you should enroll in a different CS programme.

Boru

[HappySkeptic]

No-one is going to help you on such a generic question.  First, write a series of performance tests with timings.  Then, use the a performance tool on whatever Javascript system you are on (the one in Chrome are good).  Look for hot spots in the bottom-up profiling.

When coding for performance, I always have an idea of the performance I'm expecting.  I break down the pieces and check the speed of each.  If you aren't testing with actual numbers, you have nothing to go by.

Whence am I supposed to know all those things? I am just a third-year computer science student. And I have also been using a hell lots of things we haven't been taught at the university in my program.

A performance test is just a test program.  It could be part of a unit-test.  Just have it do something in a loop 1000 times (or some large-enough number). In Javascript

Code:

var start = performance.now();
const iterations = 1000;
for (let i = 0; i < iterations; i++) {
    // Do some testing work
}
var stop = performance.now();
console.log("Test 1 runs in " + ((stop - start)/iterations) + " ms.");

You said your program is "slow".  How do you know?  You must have expectations.  At least this way you can check if something is slow or not, and find out if you fixed it or not, by comparing these numbers.

If something is slow, do a bunch of work in the loop, and do performance timing using the F12 developer console Performance tab in Chrome.  You can start the recording from some "pause" point in your code, or you can start it with a page reload, and stop it when your code has finished.  Look for the bottom-up methods, and check for calls that use a majority of the time.

[bennyboy]

@bennyboy , you say you are an experienced web developer. Could you please look into my PicoBlaze Simulator in JavaScript and tell me how I could speed it up? I cannot diagnose why it is so slow.

Yes, I think so.  This is not really a web issue, though-- it would be the same in any language running under any framework.

In `assembler.js`, your main loop, "assemble", has 2 problems:

1)  From an engineering perspective, it is absolutely unreadable.  I've never seen that many if/else statements on a single page in my life.  Let's say you have one or two mistakes in all those statements-- hell if you'll find ANYONE willing to go through that pile of spaghetti to find them.

2)  From an efficiency perspective, you seem to be doing dozens (hundreds?) of conditional operations on each node.  You need to use switch statements or some other type of logic to reduce unnecessary checks.

Also: you have this

Code:

if (node.children[0].getRegisterNumber(context.namedRegisters) === "none") DoErrorStuff{};

multiple times.  Why not just assign that equation to a bool and use that?  (Again, I don't really use JavaScript, so you can fix the syntax if it's not right)

Code:

var IsRegister = node.children[0].getRegisterNumber(context.namedRegisters) !== "none"
. . .

if (!IsRegister) DoErrorStuff{}; // Use this the next 1000 times you need the same exact check

Then your poor CPU doesn't have to keep running the same eqaulity check 1000 times.

[FlatAssembler]

@bennyboy , you say you are an experienced web developer. Could you please look into my PicoBlaze Simulator in JavaScript and tell me how I could speed it up? I cannot diagnose why it is so slow.

Yes, I think so.  This is not really a web issue, though-- it would be the same in any language running under any framework.

In `assembler.js`, your main loop, "assemble", has 2 problems:

1)  From an engineering perspective, it is absolutely unreadable.  I've never seen that many if/else statements on a single page in my life.  Let's say you have one or two mistakes in all those statements-- hell if you'll find ANYONE willing to go through that pile of spaghetti to find them.

2)  From an efficiency perspective, you seem to be doing dozens (hundreds?) of conditional operations on each node.  You need to use switch statements or some other type of logic to reduce unnecessary checks.

Also: you have this

Code:

if (node.children[0].getRegisterNumber(context.namedRegisters) === "none") DoErrorStuff{};

multiple times.  Why not just assign that equation to a bool and use that?  (Again, I don't really use JavaScript, so you can fix the syntax if it's not right)

Code:

var IsRegister = node.children[0].getRegisterNumber(context.namedRegisters) !== "none"
. . .

if (!IsRegister) DoErrorStuff{}; // Use this the next 1000 times you need the same exact check

Then your poor CPU doesn't have to keep running the same eqaulity check 1000 times.

Thank you, it would be a good thing to speed up the assembler a bit. But the assembler is, at least for the test programs, already running at an acceptable speed. It is the simulator that is running way too slowly.