[dev.power64] gc: convert Bits to a uint64 array

So far all of our architectures have had at most 32 registers,
so we've been able to use entry 0 in the Bits uint32 array
directly as a register mask.  Power64 has 64 registers, so
this converts Bits to a uint64 array so we can continue to use
entry 0 directly as a register mask on Power64.

LGTM=rsc
R=rsc
CC=golang-codereviews
https://codereview.appspot.com/169060043

2 files changed, 28 insertions, 18 deletions

diff --git a/src/cmd/gc/bits.c b/src/cmd/gc/bits.c
index 2e79f6f1d..fe9a168dc 100644
--- a/src/cmd/gc/bits.c
+++ b/src/cmd/gc/bits.c
@@ -95,11 +95,11 @@ int
 bnum(Bits a)
 {
 	int i;
-	int32 b;
+	uint64 b;
 
 	for(i=0; i<BITS; i++)
 		if(b = a.b[i])
-			return 32*i + bitno(b);
+			return 64*i + bitno(b);
 	fatal("bad in bnum");
 	return 0;
 }
@@ -110,27 +110,35 @@ blsh(uint n)
 	Bits c;
 
 	c = zbits;
-	c.b[n/32] = 1L << (n%32);
+	c.b[n/64] = 1LL << (n%64);
 	return c;
 }
 
-/*
 int
-bset(Bits a, uint n)
+btest(Bits *a, uint n)
 {
-	if(a.b[n/32] & (1L << (n%32)))
-		return 1;
-	return 0;
+	return (a->b[n/64] & (1LL << (n%64))) != 0;
+}
+
+void
+biset(Bits *a, uint n)
+{
+	a->b[n/64] |= 1LL << (n%64);
+}
+
+void
+biclr(Bits *a, uint n)
+{
+	a->b[n/64] &= ~(1LL << (n%64));
 }
-*/
 
 int
-bitno(int32 b)
+bitno(uint64 b)
 {
 	int i;
 
-	for(i=0; i<32; i++)
-		if(b & (1L<<i))
+	for(i=0; i<64; i++)
+		if(b & (1LL<<i))
 			return i;
 	fatal("bad in bitno");
 	return 0;
@@ -157,7 +165,7 @@ Qconv(Fmt *fp)
 			if(var[i].offset != 0)
 				fmtprint(fp, "%+lld", (vlong)var[i].offset);
 		}
-		bits.b[i/32] &= ~(1L << (i%32));
+		biclr(&bits, i);
 	}
 	return 0;
 }
diff --git a/src/cmd/gc/go.h b/src/cmd/gc/go.h
index 965a0550d..d3c4193b5 100644
--- a/src/cmd/gc/go.h
+++ b/src/cmd/gc/go.h
@@ -704,13 +704,13 @@ enum
 	Ecomplit = 1<<11,	// type in composite literal
 };
 
-#define	BITS	5
-#define	NVAR	(BITS*sizeof(uint32)*8)
+#define	BITS	3
+#define	NVAR	(BITS*sizeof(uint64)*8)
 
 typedef	struct	Bits	Bits;
 struct	Bits
 {
-	uint32	b[BITS];
+	uint64	b[BITS];
 };
 
 EXTERN	Bits	zbits;
@@ -1027,12 +1027,14 @@ int	Qconv(Fmt *fp);
 Bits	band(Bits a, Bits b);
 int	bany(Bits *a);
 int	beq(Bits a, Bits b);
-int	bitno(int32 b);
+int	bitno(uint64 b);
 Bits	blsh(uint n);
 Bits	bnot(Bits a);
 int	bnum(Bits a);
 Bits	bor(Bits a, Bits b);
-int	bset(Bits a, uint n);
+int	btest(Bits *a, uint n);
+void	biset(Bits *a, uint n);
+void	biclr(Bits *a, uint n);
 
 /*
  *	bv.c