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PDP11: Fixed bug in CSM (John Dundas)

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John Dundas said:

Bob and all,

I ran across what I believe to be a bug in the CSM code:

         case 070:                                       /* CSM */
             if (CPUT (HAS_CSM) && (MMR3 & MMR3_CSM) || (cm != MD_KER)) {

According to the Architecture Handbook, CSM may be executed only if the MMR3 bit is set AND the mode is not Kernel.  Changing the code to:

         case 070:                                       /* CSM */
             if (CPUT (HAS_CSM) && (MMR3 & MMR3_CSM) && (cm != MD_KER)) {

also has the effect of making the ZKDKB0 diagnostic much happier.

Thanks,

John
--
John A. Dundas III
This commit is contained in:
Mark Pizzolato 2013-12-06 10:48:14 -08:00
parent 6339af2dc4
commit 0774109897
1 changed files with 2 additions and 1 deletions
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3
PDP11/pdp11_cpu.c
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@ -25,6 +25,7 @@
cpu PDP-11 CPU
05-Dec-13 RMS Fixed bug in CSM (John Dundas)
23-Oct-13 RMS Fixed PS behavior on initialization and boot
10-Apr-13 RMS MMR1 does not track PC changes (Johnny Billquist)
29-Apr-12 RMS Fixed compiler warning (Mark Pizzolato)
@ -1297,7 +1298,7 @@ while (reason == 0) {
break;
case 070: /* CSM */
if ((CPUT (HAS_CSM) && (MMR3 & MMR3_CSM)) || (cm != MD_KER)) {
if (CPUT (HAS_CSM) && (MMR3 & MMR3_CSM) && (cm != MD_KER)) {
dst = dstreg? R[dstspec]: ReadW (GeteaW (dstspec));
PSW = get_PSW () & ~PSW_CC; /* PSW, cc = 0 */
STACKFILE[cm] = SP;