diff --git a/src/uxn.c b/src/uxn.c
index 612a278..fa71eae 100644
--- a/src/uxn.c
+++ b/src/uxn.c
@@ -11,42 +11,40 @@ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 WITH REGARD TO THIS SOFTWARE.
 */
 
-#define T s->dat[s->ptr - 1]
-#define N s->dat[s->ptr - 2]
-#define L s->dat[s->ptr - 3]
-#define H2 PEEK2(s->dat + s->ptr - 3)
-#define T2 PEEK2(s->dat + s->ptr - 2)
-#define N2 PEEK2(s->dat + s->ptr - 4)
-#define L2 PEEK2(s->dat + s->ptr - 6)
-
 /* Registers
-
 [ . ][ . ][ . ][ L ][ N ][ T ] <
 [ . ][ . ][ . ][   H2   ][ T ] <
 [   L2   ][   N2   ][   T2   ] <
-
 */
 
-#define HALT(c)       { return uxn_halt(u, ins, (c), pc - 1); }
-#define SET(mul, add) { if(mul > s->ptr) HALT(1) tmp = (mul & k) + add + s->ptr; if(tmp > 254) HALT(2) s->ptr = tmp; }
-#define PUT(o, v)     { s->dat[(Uint8)(s->ptr - 1 - (o))] = (v); }
-#define PUT2(o, v)    { tmp = (v); POKE2(s->dat + (Uint8)(s->ptr - o - 2), tmp); }
-#define DEO(a, b)     { u->dev[(a)] = (b); if((deo_mask[(a) >> 4] >> ((a) & 0xf)) & 0x1) uxn_deo(u, (a)); }
-#define DEI(a, b)     { PUT((a), ((dei_mask[(b) >> 4] >> ((b) & 0xf)) & 0x1) ? uxn_dei(u, (b)) : u->dev[(b)]) }
-#define FLIP          { s = ins & 0x40 ? &u->wst : &u->rst; }
+#define T s->dat[s->ptr - 1]
+#define N s->dat[s->ptr - 2]
+#define L s->dat[s->ptr - 3]
+#define T2 PEEK2(s->dat + s->ptr - 2)
+#define H2 PEEK2(s->dat + s->ptr - 3)
+#define N2 PEEK2(s->dat + s->ptr - 4)
+#define L2 PEEK2(s->dat + s->ptr - 6)
+
+#define HALT(c)    { return uxn_halt(u, ins, (c), pc - 1); }
+#define FLIP       { s = ins & 0x40 ? &u->wst : &u->rst; }
+#define SET(x, y)  { if(x > s->ptr) HALT(1) tmp = (x & k) + y + s->ptr; if(tmp > 254) HALT(2) s->ptr = tmp; }
+#define PUT(o, v)  { s->dat[(s->ptr - 1 - (o))] = (v); }
+#define PUT2(o, v) { tmp = (v); POKE2(s->dat + (s->ptr - o - 2), tmp); }
+#define DEO(a, b)  { u->dev[(a)] = (b); if((deo_mask[(a) >> 4] >> ((a) & 0xf)) & 0x1) uxn_deo(u, (a)); }
+#define DEI(a, b)  { PUT((a), ((dei_mask[(b) >> 4] >> ((b) & 0xf)) & 0x1) ? uxn_dei(u, (b)) : u->dev[(b)]) }
 
 int
 uxn_eval(Uxn *u, Uint16 pc)
 {
-	int t, n, l, k, tmp, ins;
-	Uint8 *ram = u->ram, opc;
+	int t, n, l, k, tmp, ins, opc;
+	Uint8 *ram = u->ram;
 	Stack *s;
 	if(!pc || u->dev[0x0f]) return 0;
 	for(;;) {
 		ins = ram[pc++];
 		k = ins & 0x80 ? 0xff : 0;
 		s = ins & 0x40 ? &u->rst : &u->wst;
-		opc = !(ins & 0x1f) ? (0 - (ins >> 5)) : ins & 0x3f;
+		opc = !(ins & 0x1f) ? (0 - (ins >> 5)) & 0xff : ins & 0x3f;
 		switch(opc) {
 			/* IMM */
 			case 0x00: /* BRK   */                          return 1;