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feat: Add Pop Count (#72)
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‎config.json

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"practices": [],
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"prerequisites": [],
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"difficulty": 2
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}, {
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"slug": "pop-count",
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"name": "Pop Count",
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"uuid": "233fde6a-79d9-4d90-8f94-2a0519352a5c",
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"practices": [],
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"prerequisites": [],
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"difficulty": 4
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}, {
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"slug": "pangram",
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"name": "Pangram",

‎exercises/practice/pop-count/.docs/instructions.append.md

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## Reserved Addresses
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No linear memory is required for this exercise.

‎exercises/practice/pop-count/.docs/instructions.md

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# Instructions
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Your task is to count the number of 1 bits in the binary representation of a number.
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## Restrictions
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Keep your hands off that bit-count functionality provided by your standard library!
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Solve this one yourself using other basic tools instead.

‎exercises/practice/pop-count/.docs/introduction.md

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# Introduction
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Your friend Eliud inherited a farm from her grandma Tigist.
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Her granny was an inventor and had a tendency to build things in an overly complicated manner.
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The chicken coop has a digital display showing an encoded number representing the positions of all eggs that could be picked up.
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Eliud is asking you to write a program that shows the actual number of eggs in the coop.
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The position information encoding is calculated as follows:
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1. Scan the potential egg-laying spots and mark down a `1` for an existing egg or a `0` for an empty spot.
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2. Convert the number from binary to decimal.
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3. Show the result on the display.
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Example 1:
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```text
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Chicken Coop:
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_ _ _ _ _ _ _
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|E| |E|E| | |E|
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Resulting Binary:
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1 0 1 1 0 0 1
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Decimal number on the display:
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89
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Actual eggs in the coop:
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4
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```
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Example 2:
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```text
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Chicken Coop:
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_ _ _ _ _ _ _ _
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| | | |E| | | | |
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Resulting Binary:
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0 0 0 1 0 0 0 0
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Decimal number on the display:
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16
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Actual eggs in the coop:
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1
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```

‎exercises/practice/pop-count/.eslintrc

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{
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"root": true,
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"extends": "@exercism/eslint-config-javascript",
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"env": {
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"jest": true
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},
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"overrides": [
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{
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"files": [
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"*.spec.js"
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],
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"excludedFiles": [
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"custom.spec.js"
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],
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"extends": "@exercism/eslint-config-javascript/maintainers"
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}
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]
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}

‎exercises/practice/pop-count/.meta/config.json

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{
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"authors": [
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"keiravillekode"
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],
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"files": {
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"solution": [
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"pop-count.wat"
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],
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"test": [
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"pop-count.spec.js"
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],
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"example": [
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".meta/proof.ci.wat"
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]
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},
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"blurb": "Count the 1 bits in a number",
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"source": "Christian Willner, Eric Willigers",
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"source_url": "https://forum.exercism.org/t/new-exercise-suggestion-pop-count/7632/5",
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"custom": {
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"version.tests.compatibility": "jest-27",
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"flag.tests.task-per-describe": false,
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"flag.tests.may-run-long": false,
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"flag.tests.includes-optional": false
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}
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}

‎exercises/practice/pop-count/.meta/proof.ci.wat

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(module
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(func (export "eggCount") (param $number i32) (result i32)
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(local $remaining i32)
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(local $count i32)
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(if (i32.eq (local.get $number) (i32.const 0))(then
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(return (i32.const 0))
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))
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(local.set $remaining (local.get $number))
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(local.set $count (i32.const 0))
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;; do while $remaining != 0
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(loop
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;; Clear least-significant 1 bit using
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;; $remaining -= $remaining & -$remaining
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(local.set $remaining (i32.sub (local.get $remaining) (i32.and (local.get $remaining) (i32.sub (i32.const 0) (local.get $remaining)))))
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(local.set $count (i32.add (local.get $count) (i32.const 1)))
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(br_if 0 (i32.ne (local.get $remaining) (i32.const 0)))
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)
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(return (local.get $count))
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)
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)

‎exercises/practice/pop-count/.meta/tests.toml

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# This is an auto-generated file. Regular comments will be removed when this
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# file is regenerated. Regenerating will not touch any manually added keys,
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# so comments can be added in a "comment" key.
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[559e789d-07d1-4422-9004-3b699f83bca3]
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description = "0 eggs"
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[97223282-f71e-490c-92f0-b3ec9e275aba]
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description = "1 egg"
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[1f8fd18f-26e9-4144-9a0e-57cdfc4f4ff5]
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description = "4 eggs"
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[0c18be92-a498-4ef2-bcbb-28ac4b06cb81]
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description = "13 eggs"

‎exercises/practice/pop-count/.npmrc

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audit=false

‎exercises/practice/pop-count/LICENSE

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MIT License
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Copyright (c) 2021 Exercism
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Permission is hereby granted, free of charge, to any person obtaining a copy
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of this software and associated documentation files (the "Software"), to deal
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in the Software without restriction, including without limitation the rights
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to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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copies of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included in all
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copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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SOFTWARE.

‎exercises/practice/pop-count/babel.config.js

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export default {
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presets: ["@exercism/babel-preset-javascript"],
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plugins: [],
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};

‎exercises/practice/pop-count/package.json

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{
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"name": "@exercism/wasm-pop-count",
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"description": "Exercism exercises in WebAssembly.",
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"type": "module",
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"private": true,
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"license": "MIT",
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"repository": {
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"type": "git",
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"url": "https://github.com/exercism/wasm",
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"directory": "exercises/practice/pop-count"
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},
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"jest": {
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"maxWorkers": 1
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},
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"devDependencies": {
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"@babel/core": "^7.20.12",
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"@exercism/babel-preset-javascript": "^0.2.1",
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"@exercism/eslint-config-javascript": "^0.6.0",
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"@types/jest": "^29.4.0",
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"@types/node": "^18.13.0",
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"babel-jest": "^29.4.2",
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"core-js": "^3.27.2",
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"eslint": "^8.34.0",
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"jest": "^29.4.2"
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},
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"dependencies": {
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"@exercism/wasm-lib": "^0.1.0"
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},
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"scripts": {
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"test": "node --experimental-vm-modules node_modules/jest/bin/jest.js ./*",
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"watch": "node --experimental-vm-modules node_modules/jest/bin/jest.js --watch ./*",
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"lint": "eslint ."
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}
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}

‎exercises/practice/pop-count/pop-count.spec.js

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import { compileWat, WasmRunner } from "@exercism/wasm-lib";
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let wasmModule;
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let currentInstance;
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beforeAll(async () => {
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try {
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const watPath = new URL("./pop-count.wat", import.meta.url);
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const { buffer } = await compileWat(watPath);
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wasmModule = await WebAssembly.compile(buffer);
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} catch (err) {
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console.log(`Error compiling *.wat: ${err}`);
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process.exit(1);
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}
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});
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describe("eggCount()", () => {
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beforeEach(async () => {
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currentInstance = null;
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if (!wasmModule) {
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return Promise.reject();
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}
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try {
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currentInstance = await new WasmRunner(wasmModule);
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return Promise.resolve();
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} catch (err) {
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console.log(`Error instantiating WebAssembly module: ${err}`);
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return Promise.reject();
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}
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});
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test("0 eggs", () => {
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expect(currentInstance.exports.eggCount(0)).toEqual(0);
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});
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xtest("1 egg", () => {
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expect(currentInstance.exports.eggCount(16)).toEqual(1);
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});
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xtest("4 eggs", () => {
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expect(currentInstance.exports.eggCount(89)).toEqual(4);
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});
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xtest("13 eggs", () => {
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expect(currentInstance.exports.eggCount(2000000000)).toEqual(13);
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});
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});

‎exercises/practice/pop-count/pop-count.wat

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(module
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(func (export "eggCount") (param $number i32) (result i32)
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(local $remaining i32)
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(local $count i32)
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(if (i32.eq (local.get $number) (i32.const 0))(then
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(return (i32.const 0))
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))
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(local.set $remaining (i32.const 0))
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(local.set $count (i32.const 0))
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;; do while $remaining != 0
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(loop
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;; Clear least-significant 1 bit using
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;; $remaining -= $remaining & -$remaining
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(local.set $remaining (i32.sub (local.get $remaining) (i32.and (local.get $remaining) (i32.sub (i32.const 0) (local.get $remaining)))))
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(local.set $count (i32.add (local.get $count) (i32.const 1)))
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(br_if 0 (i32.ne (local.get $remaining) (i32.const 0)))
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)
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(return (local.get $count))
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)
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)

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