The following function is a function of a library (The code is written in Solidity). It has an assembly instruction that I do not understand. Specifically at line call(sub(gas, 2000), 6, 0, input, 0xc0, r, 0x60).
From the docs:
call(g, a, v, in, insize, out, outsize)call contract at address a with input mem[in..(in+insize)) providing g gas and v wei and output area mem[out..(out+outsize)) returning 0 on error (eg. out of gas) and 1 on success
function addition(G1Point p1, G1Point p2) internal returns (G1Point r) { uint[4] memory input; input[0] = p1.X; input[1] = p1.Y; input[2] = p2.X; input[3] = p2.Y; bool success; assembly { success := call(sub(gas, 2000), 6, 0, input, 0xc0, r, 0x60) // Use "invalid" to make gas estimation work switch success case 0 { invalid() } } require(success); } Why the address field a is a simple integer ? Is it referring to an internal library function ? If yes how is the numbering defined ?
Tell me ff you want me to provide the full code of the library.
EDIT
I think I found it. Is the address of the a precompiled contract ?
