accept CALL $(constant) to call absolute PC

R=ken
OCL=34845
CL=34845

src/cmd/8a/a.y

@@ -285,6 +285,7 @@ rom:
 	}
 |	reg
 |	omem
+|	imm
 
 rim:
 	rem

src/cmd/8l/l.h

@@ -193,6 +193,7 @@ enum
 	Z_rp,
 	Zbr,
 	Zcall,
+	Zcallcon,
 	Zib_,
 	Zib_rp,
 	Zibo_m,

src/cmd/8l/optab.c

@@ -260,7 +260,8 @@ uchar	yloop[] =
 uchar	ycall[] =
 {
 	Ynone,	Yml,	Zo_m,	2,
-	Ynone,	Ybr,	Zcall,	1,
+	Ynone,	Ybr,	Zcall,	0,
+	Ynone,	Yi32,	Zcallcon,	1,
 	0
 };
 uchar	yjmp[] =

src/cmd/8l/span.c

@@ -1109,6 +1109,15 @@ found:
 		}
 		break;
 
+	case Zcallcon:
+		v = p->to.offset - p->pc - 5;
+		*andptr++ = op;
+		*andptr++ = v;
+		*andptr++ = v>>8;
+		*andptr++ = v>>16;
+		*andptr++ = v>>24;
+		break;
+
 	case Zjmp:
 		q = p->pcond;
 		if(q) {