MFC r269077 (sbruno): libstand qdivrem warning fixes

  libstand's qdivrem.c assumes that sizeof(int) == sizeof(long), this is not
  true on amd64 I'm not quite positive this is the "correct" solution for
  this but it does seem to compile and shut up the spew of warnings when
  compiling libstand for userboot.

  Add two _Static_asserts() so that in the future somebody will get a compile
  failure if an architecture develops that violates the assumptions of this
  code. (strongly suggested by jmg)

  Change commetns to indicate int types instead of long.  (noted by ian in
  phabric review)

  Phabric:    https://phabric.freebsd.org/D443

2 files changed, 14 insertions, 13 deletions

diff --git a/lib/libstand/qdivrem.c b/lib/libstand/qdivrem.c
index 3a18eed..bde3b0d 100644
--- a/lib/libstand/qdivrem.c
+++ b/lib/libstand/qdivrem.c
@@ -46,14 +46,13 @@ __FBSDID("$FreeBSD$");
 #define	B	(1 << HALF_BITS)	/* digit base */
 
 /* Combine two `digits' to make a single two-digit number. */
-#define	COMBINE(a, b) (((u_long)(a) << HALF_BITS) | (b))
+#define	COMBINE(a, b) (((u_int)(a) << HALF_BITS) | (b))
+
+_Static_assert(sizeof(int) / 2 == sizeof(short),
+	"Bitwise functions in libstand are broken on this architecture\n");
 
 /* select a type for digits in base B: use unsigned short if they fit */
-#if ULONG_MAX == 0xffffffff && USHRT_MAX >= 0xffff
 typedef unsigned short digit;
-#else
-typedef u_long digit;
-#endif
 
 /*
  * Shift p[0]..p[len] left `sh' bits, ignoring any bits that
@@ -74,7 +73,7 @@ shl(digit *p, int len, int sh)
  * __qdivrem(u, v, rem) returns u/v and, optionally, sets *rem to u%v.
  *
  * We do this in base 2-sup-HALF_BITS, so that all intermediate products
- * fit within u_long.  As a consequence, the maximum length dividend and
+ * fit within u_int.  As a consequence, the maximum length dividend and
  * divisor are 4 `digits' in this base (they are shorter if they have
  * leading zeros).
  */
@@ -85,7 +84,7 @@ __qdivrem(uq, vq, arq)
 	union uu tmp;
 	digit *u, *v, *q;
 	digit v1, v2;
-	u_long qhat, rhat, t;
+	u_int qhat, rhat, t;
 	int m, n, d, j, i;
 	digit uspace[5], vspace[5], qspace[5];
 
@@ -136,7 +135,7 @@ __qdivrem(uq, vq, arq)
 	v[4] = LHALF(tmp.ul[L]);
 	for (n = 4; v[1] == 0; v++) {
 		if (--n == 1) {
-			u_long rbj;	/* r*B+u[j] (not root boy jim) */
+			u_int rbj;	/* r*B+u[j] (not root boy jim) */
 			digit q1, q2, q3, q4;
 
 			/*
@@ -212,7 +211,7 @@ __qdivrem(uq, vq, arq)
 			rhat = uj1;
 			goto qhat_too_big;
 		} else {
-			u_long nn = COMBINE(uj0, uj1);
+			u_int nn = COMBINE(uj0, uj1);
 			qhat = nn / v1;
 			rhat = nn % v1;
 		}
diff --git a/lib/libstand/quad.h b/lib/libstand/quad.h
index 0ff27ff..349540a 100644
--- a/lib/libstand/quad.h
+++ b/lib/libstand/quad.h
@@ -54,6 +54,9 @@
 #include <sys/types.h>
 #include <limits.h>
 
+_Static_assert(sizeof(quad_t) == sizeof(int) * 2,
+	"Bitwise function in libstand are broken on this architecture\n");
+
 /*
  * Depending on the desired operation, we view a `long long' (aka quad_t) in
  * one or more of the following formats.
@@ -61,8 +64,8 @@
 union uu {
 	quad_t	q;		/* as a (signed) quad */
 	quad_t	uq;		/* as an unsigned quad */
-	long	sl[2];		/* as two signed longs */
-	u_long	ul[2];		/* as two unsigned longs */
+	int	sl[2];		/* as two signed ints */
+	u_int	ul[2];		/* as two unsigned ints */
 };
 
 /*
@@ -77,8 +80,7 @@ union uu {
  * and assembly.
  */
 #define	QUAD_BITS	(sizeof(quad_t) * CHAR_BIT)
-#define	LONG_BITS	(sizeof(long) * CHAR_BIT)
-#define	HALF_BITS	(sizeof(long) * CHAR_BIT / 2)
+#define	HALF_BITS	(sizeof(int) * CHAR_BIT / 2)
 
 /*
  * Extract high and low shortwords from longword, and move low shortword of