d3d10/effect: Add support for 'iadd' instruction.

dlls/d3d10/effect.c

@@ -388,6 +388,20 @@ static void pres_div(float **args, unsigned int n, const struct preshader_instr
         retval[i] = args[0][instr->scalar ? 0 : i] / args[1][i];
 }
 
+static void pres_iadd(float **args, unsigned int n, const struct preshader_instr *instr)
+{
+    int *arg1 = (int *)args[0];
+    int *arg2 = (int *)args[1];
+    float *retval = args[2];
+    unsigned int i;
+
+    for (i = 0; i < instr->comp_count; ++i)
+    {
+        int v = arg1[instr->scalar ? 0 : i] + arg2[i];
+        retval[i] = *(float *)&v;
+    }
+}
+
 static void pres_udiv(float **args, unsigned int n, const struct preshader_instr *instr)
 {
     unsigned int *arg1 = (unsigned int *)args[0];
@@ -492,6 +506,7 @@ static const struct preshader_op_info preshader_ops[] =
     { 0x205, "mul",  pres_mul  },
     { 0x206, "atan2",pres_atan2},
     { 0x208, "div",  pres_div  },
+    { 0x216, "iadd", pres_iadd },
     { 0x21a, "udiv", pres_udiv },
     { 0x21d, "imin", pres_imin },
     { 0x21e, "imax", pres_imax },