There are differences between the IFRS and GAAP $($after FASB issued ASU $2021-04$ to simplify the accounting for goodwill impairment$)$ regarding the following:

$-$ Assignment$/$allocation of goodwill. $($i$.$e$.,$ The levels at which goodwill is assigned $/$allocated$)$

$-$ Impairment of goodwill and test$($s$)$ applied and its steps $($i$.$e$.,$ Methods of determining impairment of goodwill$)$

$-$ How impairment loss is recognized and allocated. $($i$.$e$.,$ impairment loss$[$charge$]$ calculation and allocation$)$

$-$ Amortization and impairment of intangible assets other than goodwill

Discuss the accounting treatment of the preceding points under IFRS only. $($Comparison is not required$)$