Make the flag properties use '< 0'.

When interpreting the truth value of an integer in a SIMD value, use the
'< 0' convention.

Author: sunfishcode

src/ecmascript_simd.js

@@ -54,6 +54,13 @@ _PRIVATE.maxNum = function(x, y) {
     return x != x ? y :
            y != y ? x :
            Math.max(x, y);
+
+_PRIVATE.tobool = function(x) {
+  return x < 0;
+}
+
+_PRIVATE.frombool = function(x) {
+  return !x - 1;
 }
 
 function checkFloat32x4(t) {
@@ -2171,19 +2178,19 @@ Object.defineProperty(SIMD.int32x4.prototype, 'w', {
 });
 
 Object.defineProperty(SIMD.int32x4.prototype, 'flagX', {
-  get: function() { return this.x_ != 0x0; }
+  get: function() { return _PRIVATE.tobool(this.x_); }
 });
 
 Object.defineProperty(SIMD.int32x4.prototype, 'flagY', {
-  get: function() { return this.y_ != 0x0; }
+  get: function() { return _PRIVATE.tobool(this.y_); }
 });
 
 Object.defineProperty(SIMD.int32x4.prototype, 'flagZ', {
-  get: function() { return this.z_ != 0x0; }
+  get: function() { return _PRIVATE.tobool(this.z_); }
 });
 
 Object.defineProperty(SIMD.int32x4.prototype, 'flagW', {
-  get: function() { return this.w_ != 0x0; }
+  get: function() { return _PRIVATE.tobool(this.w_); }
 });
 
 /**

src/ecmascript_simd_tests.js

@@ -1937,10 +1937,14 @@ test('int32x4 and', function() {
   equal(0x55555555, n.y);
   equal(0x55555555, n.z);
   equal(0x55555555, n.w);
-  equal(true, n.flagX);
-  equal(true, n.flagY);
-  equal(true, n.flagZ);
-  equal(true, n.flagW);
+  equal(true, m.flagX);
+  equal(true, m.flagY);
+  equal(true, m.flagZ);
+  equal(true, m.flagW);
+  equal(false, n.flagX);
+  equal(false, n.flagY);
+  equal(false, n.flagZ);
+  equal(false, n.flagW);
   var o = SIMD.int32x4.and(m,n);  // and
   equal(0x0, o.x);
   equal(0x0, o.y);