The return address transmitted to the called function

A sequential call jal sets register ra to the return address.
A parallel call p_jal clears register ra.
In the example, the call to par1 (i.e. jal par1) saves address join in register ra.
A forked call (e.g. call to f with p_jal ra, t0, f or call to g with p_jal ra, t0, g) transmits a copy of register ra before the call with instruction p_swcv t6, ra, 0.
In the example, core 0, hart 0 transmits address join to core 0, hart 1. The transmitted address is received in core 0, hart 1 with instruction p_lwcv ra, 0.
The join address is propagated to core 1, hart 0 when function g is called, with a p_swcv t6, ra, 0 and p_lwcv ra, 0 pair.
When g ends, the ending p_jalr return instruction ends core 1, hart 0 but also restarts core 0, hart 0 at the return address join.