From 07ea411d3e6d6fb1f42a1493b02e8ac48a79c13e Mon Sep 17 00:00:00 2001
From: Bob Supnik <bob@supnik.org>
Date: Thu, 16 Jun 2022 16:13:46 -0700
Subject: [PATCH] PDP8: Zeroed result exponent in double precision (COVERITY)
---
PDP8/pdp8_cpu.c | 1 +
PDP8/pdp8_fpp.c | 9 +++++++--
2 files changed, 8 insertions(+), 2 deletions(-)
diff --git a/PDP8/pdp8_cpu.c b/PDP8/pdp8_cpu.c
index c91c6c98..1fce64d9 100644
--- a/PDP8/pdp8_cpu.c
+++ b/PDP8/pdp8_cpu.c
@@ -25,6 +25,7 @@
cpu central processor
+ 21-Oct-21 RMS Fixed bug in reporting device conflicts (Hans-Bernd Eggenstein)
07-Sep-17 RMS Fixed sim_eval declaration in history routine (COVERITY)
09-Mar-17 RMS Fixed PCQ_ENTRY for interrupts (COVERITY)
13-Feb-17 RMS RESET clear L'AC, per schematics
diff --git a/PDP8/pdp8_fpp.c b/PDP8/pdp8_fpp.c
index a96c89b1..8113c848 100644
--- a/PDP8/pdp8_fpp.c
+++ b/PDP8/pdp8_fpp.c
@@ -1,6 +1,6 @@
/* pdp8_fpp.c: PDP-8 floating point processor (FPP8A)
- Copyright (c) 2007-2021, Robert M Supnik
+ Copyright (c) 2007-2022, Robert M Supnik
Permission is hereby granted, free of charge, to any person obtaining a
copy of this software and associated documentation files (the "Software"),
@@ -25,6 +25,7 @@
fpp FPP8A floating point processor
+ 11-Mar-22 RMS Zeroed result exponent in double precision (COVERITY)
05-Jan-22 RHM Fix fencepost error in FP multiply for extended
precision
21-Oct-21 RMS Added device number display
@@ -842,6 +843,7 @@ if (fpp_sta & FPS_DP) { /* dp? */
uint32 cout = fpp_fr_add (z.fr, x.fr, y.fr, EXTEND);/* z = a + b */
uint32 zsign = z.fr[0] & FPN_FRSIGN;
cout = (cout? 04000: 0); /* make sign bit */
+ z.exp = 0; /* not used in DP */
/* overflow is indicated when signs are equal and overflow does not
match the result sign bit */
fpp_copy (a, &z); /* result is z */
@@ -897,8 +899,10 @@ if ((fpp_fr_test(y.fr, 0, EXACT-1) == 0) && (y.fr[EXACT-1] < 2)) {
y.exp = 0;
y.fr[EXACT-1] = 0;
}
-if (fpp_sta & FPS_DP) /* dp? */
+if (fpp_sta & FPS_DP) { /* dp? */
fpp_fr_mul (z.fr, x.fr, y.fr, TRUE); /* mult frac */
+ z.exp = 0; /* not used in DP */
+ }
else { /* fp or ep */
fpp_norm (&x, EXACT);
fpp_norm (&y, EXACT);
@@ -934,6 +938,7 @@ if (fpp_sta & FPS_DP) { /* dp? */
fpp_dump_apt (fpp_apta, FPS_IOVX); /* error */
return;
}
+ z.exp = 0; /* not used in DP */
fpp_copy (a, &z); /* result is z */
}
else { /* fp or ep */