arb1: use MAD opcode for SRCMOD_SIGN instead of a SUB+MUL pair.

icculus · Apr 18, 2012 · ebff5a5 · ebff5a5
1 parent 638aa90
commit ebff5a5
Showing 1 changed file with 3 additions and 4 deletions.
diff --git a/mojoshader.c b/mojoshader.c
@@ -3807,10 +3807,9 @@ static const char *make_ARB1_srcarg_string_in_buf(Context *ctx,
             premod_str = "-";
             // fall through.
         case SRCMOD_SIGN:
-            output_line(ctx, "SUB %s, %s, { 0.5, 0.5, 0.5, 0.5 };",
-                        regtype_str, buf);
-            output_line(ctx, "MUL %s, %s, { 2.0, 2.0, 2.0, 2.0 };",
-                        regtype_str, regtype_str);
+            output_line(ctx,
+                "MAD %s, %s, { 2.0, 2.0, 2.0, 2.0 }, { -1.0, -1.0, -1.0, -1.0 };",
+                regtype_str, buf);
             break;
 
         case SRCMOD_COMPLEMENT: