websnark/src/build_mem.js
2019-04-09 12:37:39 -07:00

128 lines
4.2 KiB
JavaScript

/*
Copyright 2019 0KIMS association.
This file is part of websnark (Web Assembly zkSnark Prover).
websnark is a free software: you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
websnark is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
License for more details.
You should have received a copy of the GNU General Public License
along with websnark. If not, see <https://www.gnu.org/licenses/>.
*/
module.exports = function buildMem(module, prefix, prefixField) {
function buildCopy() {
const f = module.addFunction(prefix+"copy");
f.addParam("s", "i32");
f.addParam("d", "i32");
f.addParam("n", "i32");
f.addLocal("bytesAfter", "i32");
f.addLocal("sp", "i32");
const c = f.getCodeBuilder();
f.addCode(
c.setLocal(
"n64",
c.i32_shl(
c.getLocal("n"),
c.i32_const(3)
)
),
c.setLocal(
"bytesAfter",
c.i32_and(
c.getLocal("n"),
c.i32_const(0x7)
)
),
c.setLocal("sp", c.getLocal("s")),
c.setLocal("dp", c.getLocal("d")),
c.setLocal("lastsp",
c.add(
c.getLocal("s"),
c.i32_and(
c.getLocal("n"),
c.i32_const(0xFFFFFFF8)
)
)
),
c.block(c.loop(
c.br_if(
1,
c.i32_eq(
c.getLocal("sp"),
c.getLocal("lastsp")
)
),
c.i64_store(
c.getLocal("dp"),
c.i64_load(
c.getLocal("sp")
)
),
c.setLocal("sp", c.i32_add(c.getLocal("sp"), c.i32_const(8))),
c.setLocal("dp", c.i32_add(c.getLocal("dp"), c.i32_const(8))),
c.br(0)
)),
c.if(
c.getLocal("bytesAfter"),
[
...c.if(
c.i32_and(c.getLocal("bytesAfter"), c.i32_const(0x4)),
[
...c.i32_store(
c.getLocal("dp"),
c.i32_load(
c.getLocal("sp")
)
),
...c.setLocal("sp", c.i32_add(c.getLocal("sp"), c.i32_const(4))),
...c.setLocal("dp", c.i32_add(c.getLocal("dp"), c.i32_const(4))),
]
),
...c.if(
c.i32_and(c.getLocal("bytesAfter"), c.i32_const(0x2)),
[
...c.i32_store16(
c.getLocal("dp"),
c.i32_load16(
c.getLocal("sp")
)
),
...c.setLocal("sp", c.i32_add(c.getLocal("sp"), c.i32_const(2))),
...c.setLocal("dp", c.i32_add(c.getLocal("dp"), c.i32_const(2))),
]
),
...c.if(
c.i32_and(c.getLocal("bytesAfter"), c.i32_const(0x1)),
c.i32_store8(
c.getLocal("dp"),
c.i32_load8(
c.getLocal("sp")
)
)
)
]
)
);
}
buildCopy();
module.exportFunction(prefix+"_copy");
return prefix;
};