folkert/simh-testsetgenerator
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Clear storage and branch preserves B register (Van Snyder)

Browse source
This commit is contained in:
Mark Pizzolato 2013-08-22 15:50:08 -07:00
parent 18461f510b
commit 938b75fc44
1 changed files with 14 additions and 2 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

16
I1401/i1401_cpu.c
View file

@ -1,6 +1,6 @@
/* i1401_cpu.c: IBM 1401 CPU simulator
Copyright (c) 1993-2011, Robert M. Supnik
Copyright (c) 1993-2012, 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"),
@ -23,6 +23,7 @@
used in advertising or otherwise to promote the sale, use or other dealings
in this Software without prior written authorization from Robert M Supnik.
08-Oct-12 RMS Clear storage and branch preserves B register (Van Snyder)
19-Mar-11 RMS Reverted multiple tape indicator implementation
20-Jan-11 RMS Fixed branch on EOT indicator per hardware (Van Snyder)
07-Nov-10 RMS Fixed divide not to clear word marks in quotient
@ -178,6 +179,14 @@ typedef struct {
PCQ_ENTRY; \
IS = AS;
#define BRANCH_CS if (ADDR_ERR (AS)) { \
reason = STOP_INVBR; \
break; \
} \
PCQ_ENTRY; \
IS = AS;
uint8 M[MAXMEMSIZE] = { 0 }; /* main memory */
int32 saved_IS = 0; /* saved IS */
int32 AS = 0; /* AS */
@ -1563,6 +1572,9 @@ CHECK_LENGTH:
5,6 invalid B-address
7 branch
8+ one operand, branch ignored
Note that clear storage and branch does not overwrite the B register,
unlike all other branches
*/
case OP_CS: /* clear storage */
@ -1572,7 +1584,7 @@ CHECK_LENGTH:
if (BS < 0) /* wrap if needed */
BS = BS + MEMSIZE;
if (ilnt == 7) { /* branch variant? */
BRANCH;
BRANCH_CS; /* special branch */
}
break;