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authordaurnimator <quae@daurnimator.com>2018-01-07 05:00:04 +1100
committerdaurnimator <quae@daurnimator.com>2018-01-07 05:02:26 +1100
commit2968965c7e531ec0121190d5a5d0e66e0774306b (patch)
tree7f4a40c8c0b340a745975e7ee5618f6f4a38624d /src
parente0089c7adee8e313f7ff7b5d84ff0ea892c05287 (diff)
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src/lvm.js: Add Math.imul shim; export new luaV_imul function
Diffstat (limited to 'src')
-rw-r--r--src/lobject.js2
-rw-r--r--src/lvm.js16
2 files changed, 16 insertions, 2 deletions
diff --git a/src/lobject.js b/src/lobject.js
index 641473e..ec4a9b3 100644
--- a/src/lobject.js
+++ b/src/lobject.js
@@ -667,7 +667,7 @@ const intarith = function(L, op, v1, v2) {
switch (op) {
case defs.LUA_OPADD: return (v1 + v2)|0;
case defs.LUA_OPSUB: return (v1 - v2)|0;
- case defs.LUA_OPMUL: return Math.imul(v1, v2);
+ case defs.LUA_OPMUL: return lvm.luaV_imul(v1, v2);
case defs.LUA_OPMOD: return lvm.luaV_mod(L, v1, v2);
case defs.LUA_OPIDIV: return lvm.luaV_div(L, v1, v2);
case defs.LUA_OPBAND: return (v1 & v2);
diff --git a/src/lvm.js b/src/lvm.js
index 9d97c17..0646716 100644
--- a/src/lvm.js
+++ b/src/lvm.js
@@ -229,7 +229,7 @@ const luaV_execute = function(L) {
let numberop1, numberop2;
if (op1.ttisinteger() && op2.ttisinteger()) {
- L.stack[ra].setivalue(Math.imul(op1.value, op2.value));
+ L.stack[ra].setivalue(luaV_imul(op1.value, op2.value));
} else if ((numberop1 = tonumber(op1)) !== false && (numberop2 = tonumber(op2)) !== false) {
L.stack[ra].setfltvalue(numberop1 * numberop2);
} else {
@@ -847,6 +847,19 @@ const luaV_objlen = function(L, ra, rb) {
ltm.luaT_callTM(L, tm, rb, rb, ra, 1);
};
+/* Shim taken from https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/imul */
+const luaV_imul = Math.imul || function(a, b) {
+ let aHi = (a >>> 16) & 0xffff;
+ let aLo = a & 0xffff;
+ let bHi = (b >>> 16) & 0xffff;
+ let bLo = b & 0xffff;
+ /*
+ ** the shift by 0 fixes the sign on the high part
+ ** the final |0 converts the unsigned value into a signed value
+ */
+ return ((aLo * bLo) + (((aHi * bLo + aLo * bHi) << 16) >>> 0) | 0);
+};
+
const luaV_div = function(L, m, n) {
if (n === 0)
ldebug.luaG_runerror(L, defs.to_luastring("attempt to divide by zero"));
@@ -1059,6 +1072,7 @@ module.exports.luaV_div = luaV_div;
module.exports.luaV_equalobj = luaV_equalobj;
module.exports.luaV_execute = luaV_execute;
module.exports.luaV_finishOp = luaV_finishOp;
+module.exports.luaV_imul = luaV_imul;
module.exports.luaV_lessequal = luaV_lessequal;
module.exports.luaV_lessthan = luaV_lessthan;
module.exports.luaV_mod = luaV_mod;