From aef609291dd382447c9edbe7717d127485a9ab4f Mon Sep 17 00:00:00 2001
From: "Eric S. Raymond" <esr@thyrsus.com>
Date: Fri, 2 Jun 2017 16:40:29 -0400
Subject: [PATCH] Simplify bitmask test/set from FORTRANish to actual C.

---
 advent.h |  2 +-
 misc.c   | 20 ++++----------------
 2 files changed, 5 insertions(+), 17 deletions(-)

diff --git a/advent.h b/advent.h
index 074836c..631cce2 100644
--- a/advent.h
+++ b/advent.h
@@ -55,7 +55,7 @@ extern void CARRY(long,long);
 extern void DROP(long,long);
 extern long ATDWRF(long);
 extern long SETBIT(long);
-extern long TSTBIT(long,long);
+extern bool TSTBIT(long,int);
 extern long RNDVOC(long,long);
 extern void BUG(long);
 extern void MAPLIN(FILE *);
diff --git a/misc.c b/misc.c
index 365d7c8..7dfa742 100644
--- a/misc.c
+++ b/misc.c
@@ -631,26 +631,14 @@ L2:	AT=I;
 /*  Utility routines (SETBIT, TSTBIT, set_seed, get_next_lcg_value,
  *  randrange, RNDVOC, BUG) */
 
-long SETBIT(long BIT) {
-long I, IND;
-
+long SETBIT(long bit) {
 /*  Returns 2**bit for use in constructing bit-masks. */
-
-	IND=1;
-	if(BIT <= 0)return(IND);
-	for (I=1; I<=BIT; I++) {
-	IND=IND+IND;
-	} /* end loop */
-	return(IND);
+    2 << bit;
 }
 
-
-
-long TSTBIT(long MASK, long BIT) {
-
+bool TSTBIT(long mask, int bit) {
 /*  Returns true if the specified bit is set in the mask. */
-
-	return(MOD(MASK/SETBIT(BIT),2) != 0);
+    return((mask & (1 << bit)) != 0);
 }
 
 void set_seed(long seedval)
-- 
2.31.1