minor comment and debug flag for dumping all oplooks.

R=rsc
APPROVED=rsc
DELTA=4  (0 added, 0 deleted, 4 changed)
OCL=31016
CL=31126

src/cmd/5l/optab.c

@@ -32,8 +32,8 @@
 
 Optab	optab[] =
 {
-	/* Data layout:
-	  OPCODE,	from, prog->reg, to,		 magic numbers? */
+	/* struct Optab:
+	  OPCODE,	from, prog->reg, to,		 type,size,param,flag */
 	{ ATEXT,	C_LEXT,	C_NONE,	C_LCON, 	 0, 0, 0 },
 	{ ATEXT,	C_LEXT,	C_REG,	C_LCON, 	 0, 0, 0 },
 	{ ATEXT,	C_ADDR,	C_NONE,	C_LCON, 	 0, 0, 0 },

src/cmd/5l/span.c

@@ -849,8 +849,8 @@ oplook(Prog *p)
 		}
 		o = orange[r].stop; /* just generate an error */
 	}
-	if(0) {
-		print("oplook %A %d %d %d\n",
+	if(debug['O']) {
+		print("oplook %A %O %O %O\n",
 			(int)p->as, a1, a2, a3);
 		print("		%d %d\n", p->from.type, p->to.type);
 	}