call — call a symbol

call symbol
call rd, symbol       # GNU-compatible explicit link-register form

call symbol transfers control and writes the return address to ra. Its canonical relocation-aware expansion can reach beyond jal’s direct range:

auipc ra, %pcrel_hi(symbol)
jalr  ra, %pcrel_lo(symbol)(ra)

The actual object uses a call relocation that keeps the pair together; the relocation spelling above is explanatory rather than a recommendation to write the pair by hand.

Is it always one instruction?

No. The assembler normally emits an auipc/jalr pair. If the final target is in range and symbol binding permits it, the linker may relax that pair to jal ra, symbol, or to an applicable compressed form when the target ISA and register constraints allow one.

Symbol binding, target distance, enabled extensions, and linker relaxation can therefore change the final expansion. The .option pic setting does not select a different canonical call form.

Register use

The ordinary form uses ra both as the link register and as the intermediate PC-relative address register. It does not consume an additional temporary. The explicit call rd, symbol form uses rd in those roles instead.

Unlike an x86 call, no return address is pushed to memory. Saving ra and building a stack frame are separate ABI responsibilities.