PDP8/pdp8_tsc.c

   1 /* pdp8_tsc.c: PDP-8 ETOS timesharing option board (TSC8-75)
   2
   3    Copyright (c) 2003-2005, Robert M Supnik
   4
   5    Permission is hereby granted, free of charge, to any person obtaining a
   6    copy of this software and associated documentation files (the "Software"),
   7    to deal in the Software without restriction, including without limitation
   8    the rights to use, copy, modify, merge, publish, distribute, sublicense,
   9    and/or sell copies of the Software, and to permit persons to whom the
  10    Software is furnished to do so, subject to the following conditions:
  11
  12    The above copyright notice and this permission notice shall be included in
  13    all copies or substantial portions of the Software.
  14
  15    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18    ROBERT M SUPNIK BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
  19    IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  20    CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  21
  22    Except as contained in this notice, the name of Robert M Supnik shall not be
  23    used in advertising or otherwise to promote the sale, use or other dealings
  24    in this Software without prior written authorization from Robert M Supnik.
  25
  26    This module is based on Bernhard Baehr's PDP-8/E simulator
  27
  28         PDP-8/E Simulator Source Code
  29
  30         Copyright ) 2001-2003 Bernhard Baehr
  31
  32         TSC8iots.c - IOTs for the TSC8-75 Board plugin
  33
  34         This program is free software; you can redistribute it and/or modify
  35         it under the terms of the GNU General Public License as published by
  36         the Free Software Foundation; either version 2 of the License, or
  37         (at your option) any later version.
  38
  39         This program is distributed in the hope that it will be useful,
  40         but WITHOUT ANY WARRANTY; without even the implied warranty of
  41         MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  42         GNU General Public License for more details.
  43
  44         You should have received a copy of the GNU General Public License
  45         along with this program; if not, write to the Free Software
  46         Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  47
  48    tsc          TSC8-75 option board
  49 */
  50
  51 #include "pdp8_defs.h"
  52
  53 extern int32 int_req;
  54 extern int32 SF;
  55 extern int32 tsc_ir;                                    /* "ERIOT" */
  56 extern int32 tsc_pc;                                    /* "ERTB" */
  57 extern int32 tsc_cdf;                                   /* "ECDF" */
  58 extern int32 tsc_enb;                                   /* enable */
  59
  60 #define UNIT_V_SN699    (UNIT_V_UF + 0)                 /* SN 699 or above */
  61 #define UNIT_SN699      (1 << UNIT_V_SN699)
  62
  63 DEVICE tsc_dev;
  64 int32 tsc (int32 IR, int32 AC);
  65 t_stat tsc_reset (DEVICE *dptr);
  66
  67 /* TSC data structures
  68
  69    tsc_dev      TSC device descriptor
  70    tsc_unit     TSC unit descriptor
  71    tsc_reg      TSC register list
  72 */
  73
  74 DIB tsc_dib = { DEV_TSC, 1, { &tsc } };
  75
  76 UNIT tsc_unit = { UDATA (NULL, UNIT_SN699, 0) };
  77
  78 REG tsc_reg[] = {
  79     { ORDATA (IR, tsc_ir, 12) },
  80     { ORDATA (PC, tsc_pc, 12) },
  81     { FLDATA (CDF, tsc_cdf, 0) },
  82     { FLDATA (ENB, tsc_enb, 0) },
  83     { FLDATA (INT, int_req, INT_V_TSC) },
  84     { NULL }
  85     };
  86
  87 MTAB tsc_mod[] = {
  88     { UNIT_SN699, UNIT_SN699, "ESME", "ESME", NULL },
  89     { UNIT_SN699, 0, "no ESME", "NOESME", NULL },
  90     { 0 }
  91     };
  92
  93 DEVICE tsc_dev = {
  94     "TSC", &tsc_unit, tsc_reg, tsc_mod,
  95     1, 10, 31, 1, 8, 8,
  96     NULL, NULL, &tsc_reset,
  97     NULL, NULL, NULL,
  98     &tsc_dib, DEV_DISABLE | DEV_DIS
  99     };
 100
 101 /* IOT routine */
 102
 103 int32 tsc (int32 IR, int32 AC)
 104 {
 105 switch (IR & 07) {                                      /* decode IR<9:11> */
 106
 107     case 0:                                             /* ETDS */
 108         tsc_enb = 0;                                    /* disable int req */
 109         int_req = int_req & ~INT_TSC;                   /* clear flag */
 110         break;
 111
 112     case 1:                                             /* ESKP */
 113         return (int_req & INT_TSC)? IOT_SKP + AC: AC;   /* skip on int req */
 114
 115     case 2:                                             /* ECTF */
 116         int_req = int_req & ~INT_TSC;                   /* clear int req */
 117         break;
 118
 119     case 3:                                             /* ECDF */
 120         AC = AC | ((tsc_ir >> 3) & 07);                 /* read "ERIOT"<6:8> */
 121         if (tsc_cdf) AC = AC | IOT_SKP;                 /* if cdf, skip */
 122         tsc_cdf = 0;
 123         break;
 124
 125     case 4:                                             /* ERTB */
 126         return tsc_pc;
 127
 128     case 5:                                             /* ESME */
 129         if (tsc_unit.flags & UNIT_SN699) {              /* enabled? */
 130             if (tsc_cdf && ((tsc_ir & 070) >> 3) == (SF & 07)) {
 131                 AC = AC | IOT_SKP;
 132                 tsc_cdf = 0;
 133                 }
 134             }
 135         break;
 136
 137     case 6:                                             /* ERIOT */
 138         return tsc_ir;
 139
 140     case 7:                                             /* ETEN */
 141         tsc_enb = 1;
 142         break;
 143         }                                               /* end switch */
 144
 145 return AC;
 146 }
 147
 148 /* Reset routine */
 149
 150 t_stat tsc_reset (DEVICE *dptr)
 151 {
 152 tsc_ir = 0;
 153 tsc_pc = 0;
 154 tsc_cdf = 0;
 155 tsc_enb = 0;
 156 int_req = int_req & ~INT_TSC;
 157 return SCPE_OK;
 158 }