Wasynth/runtime/luajit.lua
2021-10-12 01:33:54 -04:00

159 lines
3.2 KiB
Lua

local bit = require('bit')
local ffi = require('ffi')
local unsign_i64 = ffi.typeof('uint64_t')
local div = {}
local le = {}
local lt = {}
local ge = {}
local gt = {}
local band = {}
local bor = {}
local bxor = {}
local bnot = {}
local shl = {}
local shr = {}
local extend = {}
local wrap = {}
local load = {}
local store = {}
-- Helper functions
local function unsign_i32(x)
if x < 0 then x = x + 0x100000000 end
return x
end
local function rip_u64(x) return bit.band(bit.rshift(x, 32), 0xFFFFFFFF), bit.band(x, 0xFFFFFFFF) end
local function merge_u64(hi, lo) return bit.bor(bit.lshift(hi, 32), lo) end
-- Runtime functions
local function grow_page_num(memory, num)
local old = memory.min
local new = old + num
if memory.max and new > memory.max then
return -1
else
memory.min = new
return old
end
end
function div.i32(lhs, rhs)
if rhs == 0 then error('division by zero') end
return math.floor(lhs / rhs)
end
function le.u32(lhs, rhs) return unsign_i32(lhs) <= unsign_i32(rhs) and 1 or 0 end
function lt.u32(lhs, rhs) return unsign_i32(lhs) < unsign_i32(rhs) and 1 or 0 end
function ge.u32(lhs, rhs) return unsign_i32(lhs) >= unsign_i32(rhs) and 1 or 0 end
function gt.u32(lhs, rhs) return unsign_i32(lhs) > unsign_i32(rhs) and 1 or 0 end
function le.u64(lhs, rhs) return unsign_i64(lhs) <= unsign_i64(rhs) and 1 or 0 end
function lt.u64(lhs, rhs) return unsign_i64(lhs) < unsign_i64(rhs) and 1 or 0 end
function ge.u64(lhs, rhs) return unsign_i64(lhs) >= unsign_i64(rhs) and 1 or 0 end
function gt.u64(lhs, rhs) return unsign_i64(lhs) > unsign_i64(rhs) and 1 or 0 end
band.i32 = bit.band
bor.i32 = bit.bor
bxor.i32 = bit.bxor
bnot.i32 = bit.bnot
band.i64 = bit.band
bor.i64 = bit.bor
bxor.i64 = bit.bxor
bnot.i64 = bit.bnot
shl.u32 = bit.lshift
shr.u32 = bit.rshift
shl.i32 = bit.lshift
shr.i32 = bit.rshift
shl.u64 = bit.lshift
shr.u64 = bit.rshift
shl.i64 = bit.lshift
shr.i64 = bit.rshift
extend.i32_u64 = ffi.typeof('int64_t')
wrap.i64_i32 = ffi.typeof('int32_t')
function load.i32(memory, addr)
if addr % 4 ~= 0 then error('unaligned read') end
return memory.data[addr / 4] or 0
end
function load.i32_u8(memory, addr)
local value = load.i32(memory, addr)
return bit.band(value, 0xFF)
end
function load.i64(memory, addr)
if addr % 4 ~= 0 then error('unaligned read') end
local hi = memory.data[addr / 4 + 1] or 0
local lo = memory.data[addr / 4] or 0
return merge_u64(hi, lo)
end
function store.i32(memory, addr, value)
if addr % 4 ~= 0 then error('unaligned write') end
memory.data[addr / 4] = value
end
function store.i32_n8(memory, addr, value)
if addr % 4 ~= 0 then error('unaligned write') end
local old = bit.band(memory.data[addr / 4] or 0, 0xFFFFFF00)
local new = bit.band(value, 0xFF)
memory.data[addr / 4] = bit.bor(old, new)
end
function store.i64(memory, addr, value)
if addr % 4 ~= 0 then error('unaligned write') end
local hi, lo = rip_u64(value)
memory.data[addr / 4] = lo
memory.data[addr / 4 + 1] = hi
end
return {
grow_page_num = grow_page_num,
div = div,
le = le,
lt = lt,
ge = ge,
gt = gt,
band = band,
bor = bor,
bxor = bxor,
bnot = bnot,
shl = shl,
shr = shr,
extend = extend,
wrap = wrap,
load = load,
store = store,
}