This section presents the assembler instructions that can be used for calling and returning from functions on RISC-V.

Functions can be called in different ways—directly or via a function pointer. In this section we will discuss how these types of calls will be performed.

The normal function calling instruction is the call instruction:

            call label

This is an assembler pseudo instruction that expands to two instructions in object files:

            auipc   ra, %hi(label)
            jalr    ra, ra, %lo(label)

When the linker resolves addresses, it might replace this sequence with a shorter (and faster) option if the destination is within range. Possible replacements are c.jal and jalr.