feat(p/int256): int256

[r3v4s]

This pr implements int256 package to handle huge numbers in gno.
To support this, it uses uint256 package in its own struct

there is pr to bring holiman's uint256 into gno-vm #1778

origin(go) implementation: https://github.com/mempooler/int256
gnoswap(gno) implementation: https://github.com/gnoswap-labs/gnoswap/package/big/int256

gno test metrics

gno test -v=true -print-runtime-metrics=true ./examples/gno.land/p/demo/int256

=== RUN   TestAbs
--- PASS: TestAbs (0.00s)
---       runtime: cycle=30.5k imports=3 allocs=797.6k(0.16%)
=== RUN   TestAbsGt
--- PASS: TestAbsGt (0.00s)
---       runtime: cycle=108.7k imports=3 allocs=2.5M(0.50%)
=== RUN   TestAdd
--- PASS: TestAdd (0.00s)
---       runtime: cycle=155.2k imports=3 allocs=4.0M(0.79%)
=== RUN   TestSub
--- PASS: TestSub (0.00s)
---       runtime: cycle=259.1k imports=3 allocs=6.3M(1.26%)
=== RUN   TestMul
--- PASS: TestMul (0.00s)
---       runtime: cycle=278.4k imports=3 allocs=7.0M(1.39%)
=== RUN   TestDiv
--- PASS: TestDiv (0.00s)
---       runtime: cycle=307.6k imports=3 allocs=8.1M(1.62%)
=== RUN   TestRem
--- PASS: TestRem (0.00s)
---       runtime: cycle=342.8k imports=3 allocs=9.5M(1.90%)
=== RUN   TestEq
--- PASS: TestEq (0.00s)
---       runtime: cycle=422.1k imports=3 allocs=11.3M(2.25%)
=== RUN   TestCmp
--- PASS: TestCmp (0.00s)
---       runtime: cycle=466.7k imports=3 allocs=12.4M(2.47%)
=== RUN   TestIsZero
--- PASS: TestIsZero (0.00s)
---       runtime: cycle=471.3k imports=3 allocs=12.6M(2.51%)
=== RUN   TestIsNeg
--- PASS: TestIsNeg (0.00s)
---       runtime: cycle=476.6k imports=3 allocs=12.8M(2.56%)
=== RUN   TestLt
--- PASS: TestLt (0.00s)
---       runtime: cycle=522.7k imports=3 allocs=14.0M(2.79%)
=== RUN   TestClone
--- PASS: TestClone (0.00s)
---       runtime: cycle=565.1k imports=3 allocs=14.9M(2.98%)
=== RUN   TestSetInt64
--- PASS: TestSetInt64 (0.00s)
---       runtime: cycle=567.2k imports=3 allocs=15.0M(3.01%)
=== RUN   TestSetUint64
--- PASS: TestSetUint64 (0.00s)
---       runtime: cycle=568.3k imports=3 allocs=15.1M(3.02%)
=== RUN   TestUint64
--- PASS: TestUint64 (0.00s)
---       runtime: cycle=605.7k imports=3 allocs=16.0M(3.21%)
=== RUN   TestInt64
--- PASS: TestInt64 (0.00s)
---       runtime: cycle=624.5k imports=3 allocs=16.5M(3.31%)
=== RUN   TestNeg
--- PASS: TestNeg (0.00s)
---       runtime: cycle=636.2k imports=3 allocs=16.9M(3.38%)
=== RUN   TestSign
--- PASS: TestSign (0.00s)
---       runtime: cycle=639.4k imports=3 allocs=17.1M(3.41%)
ok      ./examples/gno.land/p/demo/int256 	0.59s

Contributors' checklist...

• [TODO] Added new tests, or not needed, or not feasible
• Provided an example (e.g. screenshot) to aid review or the PR is self-explanatory
• Updated the official documentation or not needed
• No breaking changes were made, or a BREAKING CHANGE: xxx message was included in the description
• Added references to related issues and PRs
• Provided any useful hints for running manual tests
• [TODO] Added new benchmarks to generated graphs, if any. More info here.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 47.54%. Comparing base (eb36ec9) to head (ca21938).
Report is 6 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1848      +/-   ##
==========================================
+ Coverage   44.86%   47.54%   +2.67%     
==========================================
  Files         459      388      -71     
  Lines       67625    61279    -6346     
==========================================
- Hits        30339    29133    -1206     
+ Misses      34745    29707    -5038     
+ Partials     2541     2439     -102     

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[r3v4s]

CI fails because this pr doesn't includes uint256
It will be fine when #1778 get merge into master

[zivkovicmilos]

@r3v4s please merge master into this branch, since we added #1778

[zivkovicmilos]

Looks good 💯

I've left comments relating to adding more unit tests, and refactoring the README.
Otherwise, I think we should be good to go 🚀

Please merge master into this branch and make sure the tests are passing locally 🙏