diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/parseTools.js | 9 | ||||
| -rw-r--r-- | src/settings.js | 10 |
2 files changed, 18 insertions, 1 deletions
diff --git a/src/parseTools.js b/src/parseTools.js index 86e3c643..e37f3a99 100644 --- a/src/parseTools.js +++ b/src/parseTools.js @@ -1794,7 +1794,14 @@ function processMathop(item) { case 'add': return handleOverflow(getFastValue(idents[0], '+', idents[1], item.type), bits); case 'sub': return handleOverflow(getFastValue(idents[0], '-', idents[1], item.type), bits); case 'sdiv': case 'udiv': return makeRounding(getFastValue(idents[0], '/', idents[1], item.type), bits, op[0] === 's'); - case 'mul': return handleOverflow(getFastValue(idents[0], '*', idents[1], item.type), bits); + case 'mul': { + if (bits == 32 && PRECISE_I32_MUL) { + preciseI64MathUsed = true; + return '(i64Math.multiply(' + idents[0] + ',0,' + idents[1] + ',0),i64Math.result[0])'; + } else { + return handleOverflow(getFastValue(idents[0], '*', idents[1], item.type), bits); + } + } case 'urem': case 'srem': return getFastValue(idents[0], '%', idents[1], item.type); case 'or': { if (bits > 32) { diff --git a/src/settings.js b/src/settings.js index 75b30003..110cc246 100644 --- a/src/settings.js +++ b/src/settings.js @@ -76,6 +76,16 @@ var DOUBLE_MODE = 1; // How to load and store 64-bit doubles. Without typed arra // NaN or an infinite number. var PRECISE_I64_MATH = 1; // If enabled, i64 addition etc. is emulated - which is slow but precise. If disabled, // we use the 'double trick' which is fast but incurs rounding at high values. + // Note that we do not catch 32-bit multiplication by default (which must be done in + // 64 bits for high values for full precision) - you must manually set PRECISE_I32_MUL + // for that. +var PRECISE_I32_MUL = 1; // If enabled, i64 math is done in i32 multiplication. This is necessary if the values + // exceed the JS double-integer limit of ~52 bits. This option can normally be disabled + // because generally i32 multiplication works ok without it, and enabling it has a big + // impact on performance. + // Note that you can hand-optimize your code to avoid the need for this: If you do + // multiplications that actually need 64-bit precision inside 64-bit values, things + // will work properly. (Unless the LLVM optimizer turns them into 32-bit values?) var CLOSURE_ANNOTATIONS = 0; // If set, the generated code will be annotated for the closure // compiler. This potentially lets closure optimize the code better. |