semi polyfill for Math.imul

emscripten.py

@@ -321,12 +321,14 @@ def emscript(infile, settings, outfile, libraries=[]):
     infos = [make_table(sig, raw) for sig, raw in last_forwarded_json['Functions']['tables'].iteritems()]
     function_tables_defs = '\n'.join([info[0] for info in infos] + [info[1] for info in infos])
 
+    asm_setup = ''
     maths = ['Math.' + func for func in ['floor', 'abs', 'sqrt', 'pow', 'cos', 'sin', 'tan', 'acos', 'asin', 'atan', 'atan2', 'exp', 'log', 'ceil']]
     if settings['USE_MATH_IMUL']:
       maths += ['Math.imul']
+      asm_setup += 'if (!Math.imul) Math.imul = function(x, y) { return (x*y)|0 }; // # not a real polyfill since semantics not identical, but close and fairly fast\n'
     fundamentals = ['Math', 'Int8Array', 'Int16Array', 'Int32Array', 'Uint8Array', 'Uint16Array', 'Uint32Array', 'Float32Array', 'Float64Array']
     math_envs = ['Runtime.bitshift64', 'Math.min'] # TODO: move min to maths
-    asm_setup = '\n'.join(['var %s = %s;' % (f.replace('.', '_'), f) for f in math_envs])
+    asm_setup += '\n'.join(['var %s = %s;' % (f.replace('.', '_'), f) for f in math_envs])
     basic_funcs = ['abort', 'assert', 'asmPrintInt', 'asmPrintFloat', 'copyTempDouble', 'copyTempFloat'] + [m.replace('.', '_') for m in math_envs]
     if settings['SAFE_HEAP']: basic_funcs += ['SAFE_HEAP_LOAD', 'SAFE_HEAP_STORE', 'SAFE_HEAP_CLEAR']
     basic_vars = ['STACKTOP', 'STACK_MAX', 'tempDoublePtr', 'ABORT']