add better support for cpuid.80000001.dx for amd.

Reference: /n/atom/patch/applied/cpuidamdext
Date: Sun May 31 06:44:24 CES 2015
Signed-off-by: quanstro@quanstro.net

--- /sys/src/cmd/aux/cpuid/cpuid.c	Sun May 31 06:44:11 2015
+++ /sys/src/cmd/aux/cpuid/cpuid.c	Sun May 31 06:44:12 2015
@@ -167,7 +167,7 @@
 /* 31 */	"-31-",	"reserved"
 };
 
-char *fn80000001dx[32*2] = {
+char *intel80000001dx[32*2] = {
 /* 0 */	"-0-",	"reserved",
 /* 1 */	"-1-",	"reserved",
 /* 2 */	"-2-",	"reserved",
@@ -202,6 +202,41 @@
 /* 31 */	"-31-",	"reserved",
 };
 
+char *amd80000001dx[32*2] = {
+/* 0 */	"x87onchip",	"x87 on chip",
+/* 1 */	"vme",	"virtual x86 mode enhancement",
+/* 2 */	"de",	"debugging extensions",
+/* 3 */	"pse",	"page size extensions",
+/* 4 */	"tsc",	"timestamp counter",
+/* 5 */	"msr",	"rdmsr/wrmsr support",
+/* 6 */	"pae",	"page-size extensions",
+/* 7 */	"mce",	"machine check exception",
+/* 8 */	"cmpxch8b",	"cmpxch8b",
+/* 9 */	"apic",	"apic no chip",
+/* 10 */	"-10-",	"reserved",
+/* 11 */	"syscall",	"syscall instruction",
+/* 12 */	"mtrr",	"mtrr support",
+/* 13 */	"pge",	"pte global bit",
+/* 14 */	"mca",	"machine check architecture",
+/* 15 */	"cmov",	"conditional move",
+/* 16 */	"pat",	"page table attributes",
+/* 17 */	"pse36",	"page-size extensions (36-bits)",
+/* 18 */	"-18-",	"reserved",
+/* 19 */	"-19-",	"reserved",
+/* 20 */	"nox",	"execute disable",
+/* 21 */	"-21-",	"reserved",
+/* 22 */	"mmx-ext",	"mmx exteions",
+/* 23 */	"fxsr",	"fxsave/fxrestor",
+/* 24 */	"ffxsr",	"fxsave/fxrestor options",
+/* 25 */	"-25-",	"reserved",
+/* 26 */	"gb",	"1gb pages",
+/* 27 */	"rdtscp",	"RDTSCP supported",
+/* 28 */	"-28-",	"reserved",
+/* 29 */	"amd64",	"64-bit long mode supported",
+/* 30 */	"3dnowext",	"3d now exteions",
+/* 31 */	"3dnow",	"3d now",
+};
+
 char *intel80000001cx[32*2] = {
 /* 0 */	"lahf64",	"LAHF in 64-bit mode",
 /* 1 */	"cmp_leg",	"hyperthreading not valid",
@@ -497,13 +532,17 @@
 			memset(&r, 0, sizeof r);
 			r.ax = 0x80000001;
 			cpuid1(&r);
-			print("dx\t");
-			decodetab(fn80000001dx, r.dx, 0);
-			print("cx\t");
-			if(isamd())
+			if(isamd()){
+				print("dx\t");
+				decodetab(amd80000001dx, r.dx, 0);
+				print("cx\t");
 				decodetab(amd80000001cx, r.cx, 0);
-			else
+			}else{
+				print("dx\t");
+				decodetab(intel80000001dx, r.dx, 0);
+				print("cx\t");
 				decodetab(intel80000001cx, r.cx, 0);
+			}
 			break;
 		case 'f':
 			memset(&r, 0, sizeof r);