PDP10/pdp10_fe.c

   1 /* pdp10_fe.c: PDP-10 front end (console terminal) simulator
   2
   3    Copyright (c) 1993-2007, 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    fe           KS10 console front end
  27
  28    18-Jun-07    RMS     Added UNIT_IDLE flag to console input
  29    17-Oct-06    RMS     Synced keyboard to clock for idling
  30    28-May-04    RMS     Removed SET FE CTRL-C
  31    29-Dec-03    RMS     Added console backpressure support
  32    25-Apr-03    RMS     Revised for extended file support
  33    22-Dec-02    RMS     Added break support
  34    30-May-02    RMS     Widened COUNT to 32b
  35    30-Nov-01    RMS     Added extended SET/SHOW support
  36    23-Oct-01    RMS     New IO page address constants
  37    07-Sep-01    RMS     Moved function prototypes
  38 */
  39
  40 #include "pdp10_defs.h"
  41 #define UNIT_DUMMY      (1 << UNIT_V_UF)
  42
  43 extern d10 *M;
  44 extern int32 apr_flg;
  45 extern int32 tmxr_poll;
  46 t_stat fei_svc (UNIT *uptr);
  47 t_stat feo_svc (UNIT *uptr);
  48 t_stat fe_reset (DEVICE *dptr);
  49 t_stat fe_stop_os (UNIT *uptr, int32 val, char *cptr, void *desc);
  50
  51 /* FE data structures
  52
  53    fe_dev       FE device descriptor
  54    fe_unit      FE unit descriptor
  55    fe_reg       FE register list
  56 */
  57
  58 #define fei_unit        fe_unit[0]
  59 #define feo_unit        fe_unit[1]
  60
  61 UNIT fe_unit[] = {
  62     { UDATA (&fei_svc, UNIT_IDLE, 0), 0 },
  63     { UDATA (&feo_svc, 0, 0), SERIAL_OUT_WAIT }
  64     };
  65
  66 REG fe_reg[] = {
  67     { ORDATA (IBUF, fei_unit.buf, 8) },
  68     { DRDATA (ICOUNT, fei_unit.pos, T_ADDR_W), REG_RO + PV_LEFT },
  69     { DRDATA (ITIME, fei_unit.wait, 24), PV_LEFT },
  70     { ORDATA (OBUF, feo_unit.buf, 8) },
  71     { DRDATA (OCOUNT, feo_unit.pos, T_ADDR_W), REG_RO + PV_LEFT },
  72     { DRDATA (OTIME, feo_unit.wait, 24), REG_NZ + PV_LEFT },
  73     { NULL }
  74     };
  75
  76 MTAB fe_mod[] = {
  77     { UNIT_DUMMY, 0, NULL, "STOP", &fe_stop_os },
  78     { 0 }
  79     };
  80
  81 DEVICE fe_dev = {
  82     "FE", fe_unit, fe_reg, fe_mod,
  83     2, 10, 31, 1, 8, 8,
  84     NULL, NULL, &fe_reset,
  85     NULL, NULL, NULL
  86     };
  87
  88 /* Front end processor (console terminal)
  89
  90    Communications between the KS10 and its front end is based on an in-memory
  91    status block and two interrupt lines: interrupt-to-control (APR_ITC) and
  92    interrupt-from-console (APR_CON).  When the KS10 wants to print a character
  93    on the terminal,
  94
  95    1. It places a character, plus the valid flag, in FE_CTYOUT.
  96    2. It interrupts the front end processor.
  97    3. The front end processor types the character and then zeroes FE_CTYOUT.
  98    4. The front end procesor interrupts the KS10.
  99
 100    When the front end wants to send an input character to the KS10,
 101
 102    1. It places a character, plus the valid flag, in FE_CTYIN.
 103    2. It interrupts the KS10.
 104    3. It waits for the KS10 to take the character and clear the valid flag.
 105    4. It can then send more input (the KS10 may signal this by interrupting
 106       the front end).
 107
 108    Note that the protocol has both ambiguity (interrupt to the KS10 may mean
 109    character printed, or input character available, or both) and lack of
 110    symmetry (the KS10 does not inform the front end that it has taken an
 111    input character).
 112 */
 113
 114 void fe_intr (void)
 115 {
 116 if (M[FE_CTYOUT] & FE_CVALID) {                         /* char to print? */
 117     feo_unit.buf = (int32) M[FE_CTYOUT] & 0177;         /* pick it up */
 118     feo_unit.pos = feo_unit.pos + 1;
 119     sim_activate (&feo_unit, feo_unit.wait);            /* sched completion */
 120     }
 121 else if ((M[FE_CTYIN] & FE_CVALID) == 0) {              /* input char taken? */
 122     sim_cancel (&fei_unit);                             /* sched immediate */
 123     sim_activate (&fei_unit, 0);                        /* keyboard poll */
 124     }
 125 return;
 126 }
 127
 128 t_stat feo_svc (UNIT *uptr)
 129 {
 130 t_stat r;
 131
 132 if ((r = sim_putchar_s (uptr->buf)) != SCPE_OK) {       /* output; error? */
 133     sim_activate (uptr, uptr->wait);                    /* try again */
 134     return ((r == SCPE_STALL)? SCPE_OK: r);             /* !stall? report */
 135     }
 136 M[FE_CTYOUT] = 0;                                       /* clear char */
 137 apr_flg = apr_flg | APRF_CON;                           /* interrupt KS10 */
 138 return SCPE_OK;
 139 }
 140
 141 t_stat fei_svc (UNIT *uptr)
 142 {
 143 int32 temp;
 144
 145 sim_activate (uptr, KBD_WAIT (uptr->wait, tmxr_poll));  /* continue poll */
 146 if ((temp = sim_poll_kbd ()) < SCPE_KFLAG) return temp; /* no char or error? */
 147 if (temp & SCPE_BREAK) return SCPE_OK;                  /* ignore break */
 148 uptr->buf = temp & 0177;
 149 uptr->pos = uptr->pos + 1;
 150 M[FE_CTYIN] = uptr->buf | FE_CVALID;                    /* put char in mem */
 151 apr_flg = apr_flg | APRF_CON;                           /* interrupt KS10 */
 152 return SCPE_OK;
 153 }
 154
 155 /* Reset */
 156
 157 t_stat fe_reset (DEVICE *dptr)
 158 {
 159 fei_unit.buf = feo_unit.buf = 0;
 160 M[FE_CTYIN] = M[FE_CTYOUT] = 0;
 161 apr_flg = apr_flg & ~(APRF_ITC | APRF_CON);
 162 sim_activate_abs (&fei_unit, KBD_WAIT (fei_unit.wait, tmxr_poll));
 163 return SCPE_OK;
 164 }
 165
 166 /* Stop operating system */
 167
 168 t_stat fe_stop_os (UNIT *uptr, int32 val, char *cptr, void *desc)
 169 {
 170 M[FE_SWITCH] = IOBA_RP;                                 /* tell OS to stop */
 171 return SCPE_OK;
 172 }