From: Taylor R Campbell <campbell@mumble.net>
Date: Sun, 21 Jan 2018 15:52:51 +0000 (+0000)
Subject: Avoid shift of negative, which is undefined in C.
X-Git-Tag: mit-scheme-pucked-x11-0.3.1~7^2~327
X-Git-Url: https://birchwood-abbey.net/git?a=commitdiff_plain;h=8801c4fc0dbd70632d247a9f5bb5314ef6a61b1e;p=mit-scheme.git

Avoid shift of negative, which is undefined in C.
---

diff --git a/src/microcode/bignmint.h b/src/microcode/bignmint.h
index d1c3c02cc..8f9d904a5 100644
--- a/src/microcode/bignmint.h
+++ b/src/microcode/bignmint.h
@@ -118,7 +118,8 @@ extern void abort ();
   ((BIGNUM_RADIX / BIGNUM_DIGIT_LENGTH) - BIGNUM_DIGIT_LENGTH)
 
 #define BIGNUM_DIGIT(c) ((bignum_digit_type) (c))
-#define BIGNUM_DIGIT_ONES(n) (~ ((~ (BIGNUM_DIGIT (0))) << (n)))
+#define BIGNUM_DIGIT_ONES(n)						\
+  ((bignum_digit_type) (~ ((~ ((uintmax_t) (0))) << (n))))
 
 #define BIGNUM_START_PTR(bignum)					\
   ((BIGNUM_TO_POINTER (bignum)) + 1)