defined external registers g and m

SVN=126521

src/runtime/rt2_amd64.c

@@ -36,11 +36,11 @@ traceback(uint8 *pc, uint8 *sp, void* r15)
 	int32 counter;
 	int32 i;
 	int8* name;
-	U u;
+	G g;
 	Stktop *stktop;
 
 	// store local copy of per-process data block that we can write as we unwind
-	mcpy((byte*)&u, (byte*)r15, sizeof(U));
+	mcpy((byte*)&g, (byte*)r15, sizeof(G));
 
 	counter = 0;
 	name = "panic";
@@ -48,9 +48,9 @@ traceback(uint8 *pc, uint8 *sp, void* r15)
 		callpc = pc;
 		if((uint8*)_morestack < pc && pc < (uint8*)_endmorestack) {
 			// call site in _morestack(); pop to earlier stack block to get true caller
-			stktop = (Stktop*)u.stackbase;
-			u.stackbase = stktop->oldbase;
-			u.stackguard = stktop->oldguard;
+			stktop = (Stktop*)g.stackbase;
+			g.stackbase = stktop->oldbase;
+			g.stackguard = stktop->oldguard;
 			sp = stktop->oldsp;
 			pc = ((uint8**)sp)[1];
 			sp += 16;  // two irrelevant calls on stack - morestack, plus the call morestack made

src/runtime/runtime.c

@@ -571,9 +571,14 @@ check(void)
 	initsig();
 }
 
+extern	register	u;
+uint32	a;
+
 void
 _newproc(byte* fn, int32 siz, byte* args)
 {
+	a = u;
+
 	prints("_newproc fn=");
 	sys·printpointer(fn);
 	prints("; siz=");

src/runtime/runtime.h

@@ -2,7 +2,6 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-
 /*
  * basic types
  */
@@ -61,15 +60,15 @@ struct	Map
 	int32	unused;
 	void	(*fun[])(void);
 };
-typedef	struct	U		U;
-struct	U
+typedef	struct	G		G;
+struct	G
 {
 	byte*	stackguard;	// must not move
 	byte*	stackbase;	// must not move
-	U*	ufor;		// dbl ll of all u
-	U*	ubak;
-	U*	runqfor;	// dbl ll of runnable
-	U*	runqbak;
+	G*	ufor;		// dbl ll of all u
+	G*	ubak;
+	G*	runqfor;	// dbl ll of runnable
+	G*	runqbak;
 };
 typedef	struct	M		M;
 struct	M
@@ -77,13 +76,15 @@ struct	M
 	byte*	istackguard;	// must not move
 	byte*	istackbase;	// must not move
 };
+extern	register	G*	g;	// R15
+extern	register	M*	m;	// R14
 
 /*
  * global variables
  */
-U*	allu;
 M*	allm;
-U*	runq;
+G*	allu;
+G*	runq;
 
 /*
  * defined constants