(arith_driver, float_arith_driver): Compute (- x) by

using negation, not subtraction; this makes a difference with
IEEE floating point arithmetic (and also if integer arithmetic
is ones' complement or signed-magnitude!).

1 files changed, 2 insertions, 6 deletions

diff --git a/src/data.c b/src/data.c
index 9d3955dd3a9..cb04426edf6 100644
--- a/src/data.c
+++ b/src/data.c
@@ -2203,9 +2203,7 @@ arith_driver (code, nargs, args)
         {
         case Aadd: accum += next; break;
         case Asub:
-          if (!argnum && nargs != 1)
-            next = - next;
-          accum -= next;
+          accum = argnum ? accum - next : nargs == 1 ? - next : next;
           break;
         case Amult: accum *= next; break;
         case Adiv:
@@ -2265,9 +2263,7 @@ float_arith_driver (accum, argnum, code, nargs, args)
           accum += next;
           break;
         case Asub:
-          if (!argnum && nargs != 1)
-            next = - next;
-          accum -= next;
+          accum = argnum ? accum - next : nargs == 1 ? - next : next;
           break;
         case Amult:
           accum *= next;