Evolution of HIV from SIVs

Describe the evolution of HIV from SIVs. include how HIV-1 group P is involved , and how HIV is derived from gorillas.
you can use some of the articles below:

Origins of HIV and the AIDS pandemic.
Simian retroviruses in African apes.
Assessment of the gorilla gut virome in association with natural simian immunodeficiency virus infection.
A new human immunodeficiency virus derived from gorillas
Simian immunodeficiency virus SIVmac239 infection and simian human immunodeficiency virusSHIV89.6P infection result in progression to AIDS in cynomolgus macaques of Asian origin.