&& used instead of ||.  now diagnostic for loop too far is
correctly emitted.

(don't ask how i found this.  :-))

Reference: /n/sources/patch/applied/looptoofar
Date: Mon Nov 28 00:48:47 CET 2011
Signed-off-by: quanstro@quanstro.net

--- /sys/src/cmd/6l/span.c	Mon Nov 28 00:45:01 2011
+++ /sys/src/cmd/6l/span.c	Mon Nov 28 00:44:58 2011
@@ -1385,7 +1385,7 @@
 		q = p->pcond;
 		if(q) {
 			v = q->pc - p->pc - 2;
-			if(v < -128 && v > 127)
+			if(v < -128 || v > 127)
 				diag("loop too far: %P", p);
 			*andptr++ = op;
 			*andptr++ = v;
--- /sys/src/cmd/8l/span.c	Mon Nov 28 00:45:05 2011
+++ /sys/src/cmd/8l/span.c	Mon Nov 28 00:45:03 2011
@@ -304,24 +304,6 @@
 }
 
 int
-prefixof(Adr *a)
-{
-	switch(a->type) {
-	case D_INDIR+D_CS:
-		return 0x2e;
-	case D_INDIR+D_DS:
-		return 0x3e;
-	case D_INDIR+D_ES:
-		return 0x26;
-	case D_INDIR+D_FS:
-		return 0x64;
-	case D_INDIR+D_GS:
-		return 0x65;
-	}
-	return 0;
-}
-
-int
 oclass(Adr *a)
 {
 	long v;
@@ -352,8 +334,6 @@
 		return Yax;
 
 	case D_CL:
-		return Ycl;
-
 	case D_DL:
 	case D_BL:
 	case D_AH:
@@ -626,7 +606,7 @@
 	}
 	if(t >= D_INDIR) {
 		t -= D_INDIR;
-		if(t == D_NONE || D_CS <= t && t <= D_GS) {
+		if(t == D_NONE) {
 			*andptr++ = (0 << 6) | (5 << 0) | (r << 3);
 			put4(v);
 			return;
@@ -787,7 +767,6 @@
 	ASHRL,	Ycol,	Yml,	6,	0xac,0xad,0,0,
 
 /* extra imul */
-	AIMULW,	Yml,	Yrl,	7,	Pq,0xaf,0,0,
 	AIMULL,	Yml,	Yrl,	7,	Pm,0xaf,0,0,
 	0
 };
@@ -842,14 +821,7 @@
 	Prog *q, pp;
 	uchar *t;
 	int z, op, ft, tt;
-	long v, pre;
-
-	pre = prefixof(&p->from);
-	if(pre)
-		*andptr++ = pre;
-	pre = prefixof(&p->to);
-	if(pre)
-		*andptr++ = pre;
+	long v;
 
 	o = &optab[p->as];
 	ft = oclass(&p->from) * Ymax;
@@ -1089,7 +1061,7 @@
 		q = p->pcond;
 		if(q) {
 			v = q->pc - p->pc - 2;
-			if(v < -128 && v > 127)
+			if(v < -128 || v > 127)
 				diag("loop too far: %P", p);
 			*andptr++ = op;
 			*andptr++ = v;