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/* pdp8_cpu.c: PDP-8 CPU simulator
Copyright (c) 1993-2017, 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"),
to deal in the Software without restriction, including without limitation
the rights to use, copy, modify, merge, publish, distribute, sublicense,
and/or sell copies of the Software, and to permit persons to whom the
Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
ROBERT M SUPNIK BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
Except as contained in this notice, the name of Robert M Supnik shall not be
used in advertising or otherwise to promote the sale, use or other dealings
in this Software without prior written authorization from Robert M Supnik.
cpu central processor
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
28-Jan-17 RMS Renamed switch register variable to SR, per request
18-Sep-16 RMS Added alternate dispatch table for non-contiguous devices
17-Sep-13 RMS Fixed boot in wrong field problem (Dave Gesswein)
28-Apr-07 RMS Removed clock initialization
30-Oct-06 RMS Added idle and infinite loop detection
30-Sep-06 RMS Fixed SC value after DVI overflow (Don North)
22-Sep-05 RMS Fixed declarations (Sterling Garwood)
16-Aug-05 RMS Fixed C++ declaration and cast problems
06-Nov-04 RMS Added =n to SHOW HISTORY
31-Dec-03 RMS Fixed bug in set_cpu_hist
13-Oct-03 RMS Added instruction history
Added TSC8-75 support (Bernhard Baehr)
12-Mar-03 RMS Added logical name support
04-Oct-02 RMS Revamped device dispatching, added device number support
06-Jan-02 RMS Added device enable/disable routines
30-Dec-01 RMS Added old PC queue
16-Dec-01 RMS Fixed bugs in EAE
07-Dec-01 RMS Revised to use new breakpoint package
30-Nov-01 RMS Added RL8A, extended SET/SHOW support
16-Sep-01 RMS Fixed bug in reset routine, added KL8A support
10-Aug-01 RMS Removed register from declarations
17-Jul-01 RMS Moved function prototype
07-Jun-01 RMS Fixed bug in JMS to non-existent memory
25-Apr-01 RMS Added device enable/disable support
18-Mar-01 RMS Added DF32 support
05-Mar-01 RMS Added clock calibration support
15-Feb-01 RMS Added DECtape support
14-Apr-99 RMS Changed t_addr to unsigned
The register state for the PDP-8 is:
AC<0:11> accumulator
MQ<0:11> multiplier-quotient
L link flag
PC<0:11> program counter
IF<0:2> instruction field
IB<0:2> instruction buffer
DF<0:2> data field
UF user flag
UB user buffer
SF<0:6> interrupt save field
The PDP-8 has three instruction formats: memory reference, I/O transfer,
and operate. The memory reference format is:
0 1 2 3 4 5 6 7 8 9 10 11
+--+--+--+--+--+--+--+--+--+--+--+--+
| op |in|zr| page offset | memory reference
+--+--+--+--+--+--+--+--+--+--+--+--+
<0:2> mnemonic action
000 AND AC = AC & M[MA]
001 TAD L'AC = AC + M[MA]
010 DCA M[MA] = AC, AC = 0
011 ISZ M[MA] = M[MA] + 1, skip if M[MA] == 0
100 JMS M[MA] = PC, PC = MA + 1
101 JMP PC = MA
<3:4> mode action
00 page zero MA = IF'0'IR<5:11>
01 current page MA = IF'PC<0:4>'IR<5:11>
10 indirect page zero MA = xF'M[IF'0'IR<5:11>]
11 indirect current page MA = xF'M[IF'PC<0:4>'IR<5:11>]
where x is D for AND, TAD, ISZ, DCA, and I for JMS, JMP.
Memory reference instructions can access an address space of 32K words.
The address space is divided into eight 4K word fields; each field is
divided into thirty-two 128 word pages. An instruction can directly
address, via its 7b offset, locations 0-127 on page zero or on the current
page. All 32k words can be accessed via indirect addressing and the
instruction and data field registers. If an indirect address is in
locations 0010-0017 of any field, the indirect address is incremented
and rewritten to memory before use.
The I/O transfer format is as follows:
0 1 2 3 4 5 6 7 8 9 10 11
+--+--+--+--+--+--+--+--+--+--+--+--+
| op | device | pulse | I/O transfer
+--+--+--+--+--+--+--+--+--+--+--+--+
The IO transfer instruction sends the the specified pulse to the
specified I/O device. The I/O device may take data from the AC,
return data to the AC, initiate or cancel operations, or skip on
status.
The operate format is as follows:
+--+--+--+--+--+--+--+--+--+--+--+--+
| 1| 1| 1| 0| | | | | | | | | operate group 1
+--+--+--+--+--+--+--+--+--+--+--+--+
| | | | | | | |
| | | | | | | +--- increment AC 3
| | | | | | +--- rotate 1 or 2 4
| | | | | +--- rotate left 4
| | | | +--- rotate right 4
| | | +--- complement L 2
| | +--- complement AC 2
| +--- clear L 1
+-- clear AC 1
+--+--+--+--+--+--+--+--+--+--+--+--+
| 1| 1| 1| 1| | | | | | | | 0| operate group 2
+--+--+--+--+--+--+--+--+--+--+--+--+
| | | | | | |
| | | | | | +--- halt 3
| | | | | +--- or switch register 3
| | | | +--- reverse skip sense 1
| | | +--- skip on L != 0 1
| | +--- skip on AC == 0 1
| +--- skip on AC < 0 1
+-- clear AC 2
+--+--+--+--+--+--+--+--+--+--+--+--+
| 1| 1| 1| 1| | | | | | | | 1| operate group 3
+--+--+--+--+--+--+--+--+--+--+--+--+
| | | | \______/
| | | | |
| | +--|-----+--- EAE command 3
| | +--- AC -> MQ, 0 -> AC 2
| +--- MQ v AC --> AC 2
+-- clear AC 1
The operate instruction can be microprogrammed to perform operations
on the AC, MQ, and link.
This routine is the instruction decode routine for the PDP-8.
It is called from the simulator control program to execute
instructions in simulated memory, starting at the simulated PC.
It runs until 'reason' is set non-zero.
General notes:
1. Reasons to stop. The simulator can be stopped by:
HALT instruction
breakpoint encountered
unimplemented instruction and stop_inst flag set
I/O error in I/O simulator
2. Interrupts. Interrupts are maintained by three parallel variables:
dev_done device done flags
int_enable interrupt enable flags
int_req interrupt requests
In addition, int_req contains the interrupt enable flag, the
CIF not pending flag, and the ION not pending flag. If all
three of these flags are set, and at least one interrupt request
is set, then an interrupt occurs.
3. Non-existent memory. On the PDP-8, reads to non-existent memory
return zero, and writes are ignored. In the simulator, the
largest possible memory is instantiated and initialized to zero.
Thus, only writes outside the current field (indirect writes) need
be checked against actual memory size.
3. Adding I/O devices. These modules must be modified:
pdp8_defs.h add device number and interrupt definitions
pdp8_sys.c add sim_devices table entry
*/
#include "pdp8_defs.h"
#define PCQ_SIZE 64 /* must be 2**n */
#define PCQ_MASK (PCQ_SIZE - 1)
#define PCQ_ENTRY(x) pcq[pcq_p = (pcq_p - 1) & PCQ_MASK] = x
#define UNIT_V_NOEAE (UNIT_V_UF) /* EAE absent */
#define UNIT_NOEAE (1 << UNIT_V_NOEAE)
#define UNIT_V_MSIZE (UNIT_V_UF + 1) /* dummy mask */
#define UNIT_MSIZE (1 << UNIT_V_MSIZE)
#define OP_KSF 06031 /* for idle */
#define HIST_PC 0x40000000
#define HIST_MIN 64
#define HIST_MAX 65536
typedef struct {
int32 pc;
int32 ea;
int16 ir;
int16 opnd;
int16 lac;
int16 mq;
} InstHistory;
uint16 M[MAXMEMSIZE] = { 0 }; /* main memory */
int32 saved_LAC = 0; /* saved L'AC */
int32 saved_MQ = 0; /* saved MQ */
int32 saved_PC = 0; /* saved IF'PC */
int32 saved_DF = 0; /* saved Data Field */
int32 IB = 0; /* Instruction Buffer */
int32 SF = 0; /* Save Field */
int32 emode = 0; /* EAE mode */
int32 gtf = 0; /* EAE gtf flag */
int32 SC = 0; /* EAE shift count */
int32 UB = 0; /* User mode Buffer */
int32 UF = 0; /* User mode Flag */
int32 SR = 0; /* Switch Register */
int32 tsc_ir = 0; /* TSC8-75 IR */
int32 tsc_pc = 0; /* TSC8-75 PC */
int32 tsc_cdf = 0; /* TSC8-75 CDF flag */
int32 tsc_enb = 0; /* TSC8-75 enabled */
int32 cpu_astop = 0; /* address stop */
int16 pcq[PCQ_SIZE] = { 0 }; /* PC queue */
int32 pcq_p = 0; /* PC queue ptr */
REG *pcq_r = NULL; /* PC queue reg ptr */
int32 dev_done = 0; /* dev done flags */
int32 int_enable = INT_INIT_ENABLE; /* intr enables */
int32 int_req = 0; /* intr requests */
int32 stop_inst = 0; /* trap on ill inst */
int32 (*dev_tab[DEV_MAX])(int32 IR, int32 dat); /* device dispatch */
int32 hst_p = 0; /* history pointer */
int32 hst_lnt = 0; /* history length */
InstHistory *hst = NULL; /* instruction history */
t_stat cpu_ex (t_value *vptr, t_addr addr, UNIT *uptr, int32 sw);
t_stat cpu_dep (t_value val, t_addr addr, UNIT *uptr, int32 sw);
t_stat cpu_reset (DEVICE *dptr);
t_stat cpu_set_size (UNIT *uptr, int32 val, CONST char *cptr, void *desc);
t_stat cpu_set_hist (UNIT *uptr, int32 val, CONST char *cptr, void *desc);
t_stat cpu_show_hist (FILE *st, UNIT *uptr, int32 val, CONST void *desc);
t_bool build_dev_tab (void);
/* CPU data structures
cpu_dev CPU device descriptor
cpu_unit CPU unit descriptor
cpu_reg CPU register list
cpu_mod CPU modifier list
*/
UNIT cpu_unit = { UDATA (NULL, UNIT_FIX + UNIT_BINK, MAXMEMSIZE) };
REG cpu_reg[] = {
{ ORDATAD (PC, saved_PC, 15, "program counter") },
{ ORDATAD (AC, saved_LAC, 12, "accumulator") },
{ FLDATAD (L, saved_LAC, 12, "link") },
{ ORDATAD (MQ, saved_MQ, 12, "multiplier-quotient") },
{ ORDATAD (SR, SR, 12, "front panel switches") },
{ GRDATAD (IF, saved_PC, 8, 3, 12, "instruction field") },
{ GRDATAD (DF, saved_DF, 8, 3, 12, "data field") },
{ GRDATAD (IB, IB, 8, 3, 12, "instruction field buffter") },
{ ORDATAD (SF, SF, 7, "save field") },
{ FLDATAD (UB, UB, 0, "user mode buffer") },
{ FLDATAD (UF, UF, 0, "user mode flag") },
{ ORDATAD (SC, SC, 5, "EAE shift counter") },
{ FLDATAD (GTF, gtf, 0, "EAE greater than flag") },
{ FLDATAD (EMODE, emode, 0, "EAE mode (0 = A, 1 = B)") },
{ FLDATAD (ION, int_req, INT_V_ION, "interrupt enable") },
{ FLDATAD (ION_DELAY, int_req, INT_V_NO_ION_PENDING, "interrupt enable delay for ION") },
{ FLDATAD (CIF_DELAY, int_req, INT_V_NO_CIF_PENDING, "interrupt enable delay for CIF") },
{ FLDATAD (PWR_INT, int_req, INT_V_PWR, "power fail interrupt") },
{ FLDATAD (UF_INT, int_req, INT_V_UF, "user mode violation interrupt") },
{ ORDATAD (INT, int_req, INT_V_ION+1, "interrupt pending flags"), REG_RO },
{ ORDATAD (DONE, dev_done, INT_V_DIRECT, "device done flags"), REG_RO },
{ ORDATAD (ENABLE, int_enable, INT_V_DIRECT, "device interrupt enable flags"), REG_RO },
{ BRDATAD (PCQ, pcq, 8, 15, PCQ_SIZE, "PC prior to last JMP, JMS, or interrupt; most recent PC change first"), REG_RO+REG_CIRC },
{ ORDATA (PCQP, pcq_p, 6), REG_HRO },
{ FLDATAD (STOP_INST, stop_inst, 0, "stop on undefined instruction") },
{ ORDATAD (WRU, sim_int_char, 8, "interrupt character") },
{ NULL }
};
MTAB cpu_mod[] = {
{ UNIT_NOEAE, UNIT_NOEAE, "no EAE", "NOEAE", NULL },
{ UNIT_NOEAE, 0, "EAE", "EAE", NULL },
{ MTAB_XTD|MTAB_VDV, 0, "IDLE", "IDLE", &sim_set_idle, &sim_show_idle },
{ MTAB_XTD|MTAB_VDV, 0, NULL, "NOIDLE", &sim_clr_idle, NULL },
{ UNIT_MSIZE, 4096, NULL, "4K", &cpu_set_size },
{ UNIT_MSIZE, 8192, NULL, "8K", &cpu_set_size },
{ UNIT_MSIZE, 12288, NULL, "12K", &cpu_set_size },
{ UNIT_MSIZE, 16384, NULL, "16K", &cpu_set_size },
{ UNIT_MSIZE, 20480, NULL, "20K", &cpu_set_size },
{ UNIT_MSIZE, 24576, NULL, "24K", &cpu_set_size },
{ UNIT_MSIZE, 28672, NULL, "28K", &cpu_set_size },
{ UNIT_MSIZE, 32768, NULL, "32K", &cpu_set_size },
{ MTAB_XTD|MTAB_VDV|MTAB_NMO|MTAB_SHP, 0, "HISTORY", "HISTORY",
&cpu_set_hist, &cpu_show_hist },
{ 0 }
};
DEVICE cpu_dev = {
"CPU", &cpu_unit, cpu_reg, cpu_mod,
1, 8, 15, 1, 8, 12,
&cpu_ex, &cpu_dep, &cpu_reset,
NULL, NULL, NULL,
NULL, 0
};
t_stat sim_instr (void)
{
int32 IR, MB, IF, DF, LAC, MQ;
uint32 PC, MA;
int32 device, pulse, temp, iot_data;
t_stat reason;
/* Restore register state */
if (build_dev_tab ()) /* build dev_tab */
return SCPE_STOP;
PC = saved_PC & 007777; /* load local copies */
IF = saved_PC & 070000;
DF = saved_DF & 070000;
LAC = saved_LAC & 017777;
MQ = saved_MQ & 07777;
int_req = INT_UPDATE;
reason = 0;
/* Main instruction fetch/decode loop */
while (reason == 0) { /* loop until halted */
if (cpu_astop != 0) {
cpu_astop = 0;
reason = SCPE_STOP;
break;
}
if (sim_interval <= 0) { /* check clock queue */
if ((reason = sim_process_event ()))
break;
}
if (int_req > INT_PENDING) { /* interrupt? */
int_req = int_req & ~INT_ION; /* interrupts off */
SF = (UF << 6) | (IF >> 9) | (DF >> 12); /* form save field */
PCQ_ENTRY (IF | PC); /* save old PC with IF */
IF = IB = DF = UF = UB = 0; /* clear mem ext */
M[0] = PC; /* save PC in 0 */
PC = 1; /* fetch next from 1 */
}
MA = IF | PC; /* form PC */
if (sim_brk_summ &&
sim_brk_test (MA, (1u << SIM_BKPT_V_SPC) | SWMASK ('E'))) { /* breakpoint? */
reason = STOP_IBKPT; /* stop simulation */
break;
}
IR = M[MA]; /* fetch instruction */
if (sim_brk_summ &&
sim_brk_test (IR, (2u << SIM_BKPT_V_SPC) | SWMASK ('I'))) { /* breakpoint? */
reason = STOP_OPBKPT; /* stop simulation */
break;
}
PC = (PC + 1) & 07777; /* increment PC */
int_req = int_req | INT_NO_ION_PENDING; /* clear ION delay */
sim_interval = sim_interval - 1;
/* Instruction decoding.
The opcode (IR<0:2>), indirect flag (IR<3>), and page flag (IR<4>)
are decoded together. This produces 32 decode points, four per
major opcode. For IOT, the extra decode points are not useful;
for OPR, only the group flag (IR<3>) is used.
AND, TAD, ISZ, DCA calculate a full 15b effective address.
JMS, JMP calculate a 12b field-relative effective address.
Autoindex calculations always occur within the same field as the
instruction fetch. The field must exist; otherwise, the instruction
fetched would be 0000, and indirect addressing could not occur.
Note that MA contains IF'PC.
*/
if (hst_lnt) { /* history enabled? */
int32 ea;
hst_p = (hst_p + 1); /* next entry */
if (hst_p >= hst_lnt)
hst_p = 0;
hst[hst_p].pc = MA | HIST_PC; /* save PC, IR, LAC, MQ */
hst[hst_p].ir = IR;
hst[hst_p].lac = LAC;
hst[hst_p].mq = MQ;
if (IR < 06000) { /* mem ref? */
if (IR & 0200)
ea = (MA & 077600) | (IR & 0177);
else ea = IF | (IR & 0177); /* direct addr */
if (IR & 0400) { /* indirect? */
if (IR < 04000) { /* mem operand? */
if ((ea & 07770) != 00010)
ea = DF | M[ea];
else ea = DF | ((M[ea] + 1) & 07777);
}
else { /* no, jms/jmp */
if ((ea & 07770) != 00010)
ea = IB | M[ea];
else ea = IB | ((M[ea] + 1) & 07777);
}
}
hst[hst_p].ea = ea; /* save eff addr */
hst[hst_p].opnd = M[ea]; /* save operand */
}
}
switch ((IR >> 7) & 037) { /* decode IR<0:4> */
/* Opcode 0, AND */
case 000: /* AND, dir, zero */
MA = IF | (IR & 0177); /* dir addr, page zero */
LAC = LAC & (M[MA] | 010000);
break;
case 001: /* AND, dir, curr */
MA = (MA & 077600) | (IR & 0177); /* dir addr, curr page */
LAC = LAC & (M[MA] | 010000);
break;
case 002: /* AND, indir, zero */
MA = IF | (IR & 0177); /* dir addr, page zero */
if ((MA & 07770) != 00010) /* indirect; autoinc? */
MA = DF | M[MA];
else MA = DF | (M[MA] = (M[MA] + 1) & 07777); /* incr before use */
LAC = LAC & (M[MA] | 010000);
break;
case 003: /* AND, indir, curr */
MA = (MA & 077600) | (IR & 0177); /* dir addr, curr page */
if ((MA & 07770) != 00010) /* indirect; autoinc? */
MA = DF | M[MA];
else MA = DF | (M[MA] = (M[MA] + 1) & 07777); /* incr before use */
LAC = LAC & (M[MA] | 010000);
break;
/* Opcode 1, TAD */
case 004: /* TAD, dir, zero */
MA = IF | (IR & 0177); /* dir addr, page zero */
LAC = (LAC + M[MA]) & 017777;
break;
case 005: /* TAD, dir, curr */
MA = (MA & 077600) | (IR & 0177); /* dir addr, curr page */
LAC = (LAC + M[MA]) & 017777;
break;
case 006: /* TAD, indir, zero */
MA = IF | (IR & 0177); /* dir addr, page zero */
if ((MA & 07770) != 00010) /* indirect; autoinc? */
MA = DF | M[MA];
else MA = DF | (M[MA] = (M[MA] + 1) & 07777); /* incr before use */
LAC = (LAC + M[MA]) & 017777;
break;
case 007: /* TAD, indir, curr */
MA = (MA & 077600) | (IR & 0177); /* dir addr, curr page */
if ((MA & 07770) != 00010) /* indirect; autoinc? */
MA = DF | M[MA];
else MA = DF | (M[MA] = (M[MA] + 1) & 07777); /* incr before use */
LAC = (LAC + M[MA]) & 017777;
break;
/* Opcode 2, ISZ */
case 010: /* ISZ, dir, zero */
MA = IF | (IR & 0177); /* dir addr, page zero */
M[MA] = MB = (M[MA] + 1) & 07777; /* field must exist */
if (MB == 0)
PC = (PC + 1) & 07777;
break;
case 011: /* ISZ, dir, curr */
MA = (MA & 077600) | (IR & 0177); /* dir addr, curr page */
M[MA] = MB = (M[MA] + 1) & 07777; /* field must exist */
if (MB == 0)
PC = (PC + 1) & 07777;
break;
case 012: /* ISZ, indir, zero */
MA = IF | (IR & 0177); /* dir addr, page zero */
if ((MA & 07770) != 00010) /* indirect; autoinc? */
MA = DF | M[MA];
else MA = DF | (M[MA] = (M[MA] + 1) & 07777); /* incr before use */
MB = (M[MA] + 1) & 07777;
if (MEM_ADDR_OK (MA))
M[MA] = MB;
if (MB == 0)
PC = (PC + 1) & 07777;
break;
case 013: /* ISZ, indir, curr */
MA = (MA & 077600) | (IR & 0177); /* dir addr, curr page */
if ((MA & 07770) != 00010) /* indirect; autoinc? */
MA = DF | M[MA];
else MA = DF | (M[MA] = (M[MA] + 1) & 07777); /* incr before use */
MB = (M[MA] + 1) & 07777;
if (MEM_ADDR_OK (MA))
M[MA] = MB;
if (MB == 0)
PC = (PC + 1) & 07777;
break;
/* Opcode 3, DCA */
case 014: /* DCA, dir, zero */
MA = IF | (IR & 0177); /* dir addr, page zero */
M[MA] = LAC & 07777;
LAC = LAC & 010000;
break;
case 015: /* DCA, dir, curr */
MA = (MA & 077600) | (IR & 0177); /* dir addr, curr page */
M[MA] = LAC & 07777;
LAC = LAC & 010000;
break;
case 016: /* DCA, indir, zero */
MA = IF | (IR & 0177); /* dir addr, page zero */
if ((MA & 07770) != 00010) /* indirect; autoinc? */
MA = DF | M[MA];
else MA = DF | (M[MA] = (M[MA] + 1) & 07777); /* incr before use */
if (MEM_ADDR_OK (MA))
M[MA] = LAC & 07777;
LAC = LAC & 010000;
break;
case 017: /* DCA, indir, curr */
MA = (MA & 077600) | (IR & 0177); /* dir addr, curr page */
if ((MA & 07770) != 00010) /* indirect; autoinc? */
MA = DF | M[MA];
else MA = DF | (M[MA] = (M[MA] + 1) & 07777); /* incr before use */
if (MEM_ADDR_OK (MA))
M[MA] = LAC & 07777;
LAC = LAC & 010000;
break;
/* Opcode 4, JMS. From Bernhard Baehr's description of the TSC8-75:
(In user mode) the current JMS opcode is moved to the ERIOT register, the ECDF
flag is cleared. The address of the JMS instruction is loaded into the ERTB
register and the TSC8-75 I/O flag is raised. When the TSC8-75 is enabled, the
target addess of the JMS is loaded into PC, but nothing else (loading of IF, UF,
clearing the interrupt inhibit flag, storing of the return address in the first
word of the subroutine) happens. When the TSC8-75 is disabled, the JMS is performed
as usual. */
case 020: /* JMS, dir, zero */
PCQ_ENTRY (MA);
MA = IR & 0177; /* dir addr, page zero */
if (UF) { /* user mode? */
tsc_ir = IR; /* save instruction */
tsc_cdf = 0; /* clear flag */
}
if (UF && tsc_enb) { /* user mode, TSC enab? */
tsc_pc = (PC - 1) & 07777; /* save PC */
int_req = int_req | INT_TSC; /* request intr */
}
else { /* normal */
IF = IB; /* change IF */
UF = UB; /* change UF */
int_req = int_req | INT_NO_CIF_PENDING; /* clr intr inhibit */
MA = IF | MA;
if (MEM_ADDR_OK (MA))
M[MA] = PC;
}
PC = (MA + 1) & 07777;
break;
case 021: /* JMS, dir, curr */
PCQ_ENTRY (MA);
MA = (MA & 007600) | (IR & 0177); /* dir addr, curr page */
if (UF) { /* user mode? */
tsc_ir = IR; /* save instruction */
tsc_cdf = 0; /* clear flag */
}
if (UF && tsc_enb) { /* user mode, TSC enab? */
tsc_pc = (PC - 1) & 07777; /* save PC */
int_req = int_req | INT_TSC; /* request intr */
}
else { /* normal */
IF = IB; /* change IF */
UF = UB; /* change UF */
int_req = int_req | INT_NO_CIF_PENDING; /* clr intr inhibit */
MA = IF | MA;
if (MEM_ADDR_OK (MA))
M[MA] = PC;
}
PC = (MA + 1) & 07777;
break;
case 022: /* JMS, indir, zero */
PCQ_ENTRY (MA);
MA = IF | (IR & 0177); /* dir addr, page zero */
if ((MA & 07770) != 00010) /* indirect; autoinc? */
MA = M[MA];
else MA = (M[MA] = (M[MA] + 1) & 07777); /* incr before use */
if (UF) { /* user mode? */
tsc_ir = IR; /* save instruction */
tsc_cdf = 0; /* clear flag */
}
if (UF && tsc_enb) { /* user mode, TSC enab? */
tsc_pc = (PC - 1) & 07777; /* save PC */
int_req = int_req | INT_TSC; /* request intr */
}
else { /* normal */
IF = IB; /* change IF */
UF = UB; /* change UF */
int_req = int_req | INT_NO_CIF_PENDING; /* clr intr inhibit */
MA = IF | MA;
if (MEM_ADDR_OK (MA))
M[MA] = PC;
}
PC = (MA + 1) & 07777;
break;
case 023: /* JMS, indir, curr */
PCQ_ENTRY (MA);
MA = (MA & 077600) | (IR & 0177); /* dir addr, curr page */
if ((MA & 07770) != 00010) /* indirect; autoinc? */
MA = M[MA];
else MA = (M[MA] = (M[MA] + 1) & 07777); /* incr before use */
if (UF) { /* user mode? */
tsc_ir = IR; /* save instruction */
tsc_cdf = 0; /* clear flag */
}
if (UF && tsc_enb) { /* user mode, TSC enab? */
tsc_pc = (PC - 1) & 07777; /* save PC */
int_req = int_req | INT_TSC; /* request intr */
}
else { /* normal */
IF = IB; /* change IF */
UF = UB; /* change UF */
int_req = int_req | INT_NO_CIF_PENDING; /* clr intr inhibit */
MA = IF | MA;
if (MEM_ADDR_OK (MA))
M[MA] = PC;
}
PC = (MA + 1) & 07777;
break;
/* Opcode 5, JMP. From Bernhard Baehr's description of the TSC8-75:
(In user mode) the current JMP opcode is moved to the ERIOT register, the ECDF
flag is cleared. The address of the JMP instruction is loaded into the ERTB
register and the TSC8-75 I/O flag is raised. Then the JMP is performed as usual
(including the setting of IF, UF and clearing the interrupt inhibit flag). */
case 024: /* JMP, dir, zero */
PCQ_ENTRY (MA);
MA = IR & 0177; /* dir addr, page zero */
if (UF) { /* user mode? */
tsc_ir = IR; /* save instruction */
tsc_cdf = 0; /* clear flag */
if (tsc_enb) { /* TSC8 enabled? */
tsc_pc = (PC - 1) & 07777; /* save PC */
int_req = int_req | INT_TSC; /* request intr */
}
}
IF = IB; /* change IF */
UF = UB; /* change UF */
int_req = int_req | INT_NO_CIF_PENDING; /* clr intr inhibit */
PC = MA;
break;
/* If JMP direct, also check for idle (KSF/JMP *-1) and infinite loop */
case 025: /* JMP, dir, curr */
PCQ_ENTRY (MA);
MA = (MA & 007600) | (IR & 0177); /* dir addr, curr page */
if (UF) { /* user mode? */
tsc_ir = IR; /* save instruction */
tsc_cdf = 0; /* clear flag */
if (tsc_enb) { /* TSC8 enabled? */
tsc_pc = (PC - 1) & 07777; /* save PC */
int_req = int_req | INT_TSC; /* request intr */
}
}
if (sim_idle_enab && /* idling enabled? */
(IF == IB)) { /* to same bank? */
if (MA == ((PC - 2) & 07777)) { /* 1) JMP *-1? */
if (!(int_req & (INT_ION|INT_TTI)) && /* iof, TTI flag off? */
(M[IB|((PC - 2) & 07777)] == OP_KSF)) /* next is KSF? */
sim_idle (TMR_CLK, FALSE); /* we're idle */
} /* end JMP *-1 */
else if (MA == ((PC - 1) & 07777)) { /* 2) JMP *? */
if (!(int_req & INT_ION)) /* iof? */
reason = STOP_LOOP; /* then infinite loop */
else if (!(int_req & INT_ALL)) /* ion, not intr? */
sim_idle (TMR_CLK, FALSE); /* we're idle */
} /* end JMP */
} /* end idle enabled */
IF = IB; /* change IF */
UF = UB; /* change UF */
int_req = int_req | INT_NO_CIF_PENDING; /* clr intr inhibit */
PC = MA;
break;
case 026: /* JMP, indir, zero */
PCQ_ENTRY (MA);
MA = IF | (IR & 0177); /* dir addr, page zero */
if ((MA & 07770) != 00010) /* indirect; autoinc? */
MA = M[MA];
else MA = (M[MA] = (M[MA] + 1) & 07777); /* incr before use */
if (UF) { /* user mode? */
tsc_ir = IR; /* save instruction */
tsc_cdf = 0; /* clear flag */
if (tsc_enb) { /* TSC8 enabled? */
tsc_pc = (PC - 1) & 07777; /* save PC */
int_req = int_req | INT_TSC; /* request intr */
}
}
IF = IB; /* change IF */
UF = UB; /* change UF */
int_req = int_req | INT_NO_CIF_PENDING; /* clr intr inhibit */
PC = MA;
break;
case 027: /* JMP, indir, curr */
PCQ_ENTRY (MA);
MA = (MA & 077600) | (IR & 0177); /* dir addr, curr page */
if ((MA & 07770) != 00010) /* indirect; autoinc? */
MA = M[MA];
else MA = (M[MA] = (M[MA] + 1) & 07777); /* incr before use */
if (UF) { /* user mode? */
tsc_ir = IR; /* save instruction */
tsc_cdf = 0; /* clear flag */
if (tsc_enb) { /* TSC8 enabled? */
tsc_pc = (PC - 1) & 07777; /* save PC */
int_req = int_req | INT_TSC; /* request intr */
}
}
IF = IB; /* change IF */
UF = UB; /* change UF */
int_req = int_req | INT_NO_CIF_PENDING; /* clr intr inhibit */
PC = MA;
break;
/* Opcode 7, OPR group 1 */
case 034:case 035: /* OPR, group 1 */
switch ((IR >> 4) & 017) { /* decode IR<4:7> */
case 0: /* nop */
break;
case 1: /* CML */
LAC = LAC ^ 010000;
break;
case 2: /* CMA */
LAC = LAC ^ 07777;
break;
case 3: /* CMA CML */
LAC = LAC ^ 017777;
break;
case 4: /* CLL */
LAC = LAC & 07777;
break;
case 5: /* CLL CML = STL */
LAC = LAC | 010000;
break;
case 6: /* CLL CMA */
LAC = (LAC ^ 07777) & 07777;
break;
case 7: /* CLL CMA CML */
LAC = (LAC ^ 07777) | 010000;
break;
case 010: /* CLA */
LAC = LAC & 010000;
break;
case 011: /* CLA CML */
LAC = (LAC & 010000) ^ 010000;
break;
case 012: /* CLA CMA = STA */
LAC = LAC | 07777;
break;
case 013: /* CLA CMA CML */
LAC = (LAC | 07777) ^ 010000;
break;
case 014: /* CLA CLL */
LAC = 0;
break;
case 015: /* CLA CLL CML */
LAC = 010000;
break;
case 016: /* CLA CLL CMA */
LAC = 07777;
break;
case 017: /* CLA CLL CMA CML */
LAC = 017777;
break;
} /* end switch opers */
if (IR & 01) /* IAC */
LAC = (LAC + 1) & 017777;
switch ((IR >> 1) & 07) { /* decode IR<8:10> */
case 0: /* nop */
break;
case 1: /* BSW */
LAC = (LAC & 010000) | ((LAC >> 6) & 077) | ((LAC & 077) << 6);
break;
case 2: /* RAL */
LAC = ((LAC << 1) | (LAC >> 12)) & 017777;
break;
case 3: /* RTL */
LAC = ((LAC << 2) | (LAC >> 11)) & 017777;
break;
case 4: /* RAR */
LAC = ((LAC >> 1) | (LAC << 12)) & 017777;
break;
case 5: /* RTR */
LAC = ((LAC >> 2) | (LAC << 11)) & 017777;
break;
case 6: /* RAL RAR - undef */
LAC = LAC & (IR | 010000); /* uses AND path */
break;
case 7: /* RTL RTR - undef */
LAC = (LAC & 010000) | (MA & 07600) | (IR & 0177);
break; /* uses address path */
} /* end switch shifts */
break; /* end group 1 */
/* OPR group 2. From Bernhard Baehr's description of the TSC8-75:
(In user mode) HLT (7402), OSR (7404) and microprogrammed combinations with
HLT and OSR: Additional to raising a user mode interrupt, the current OPR
opcode is moved to the ERIOT register and the ECDF flag is cleared. */
case 036:case 037: /* OPR, groups 2, 3 */
if ((IR & 01) == 0) { /* group 2 */
switch ((IR >> 3) & 017) { /* decode IR<6:8> */
case 0: /* nop */
break;
case 1: /* SKP */
PC = (PC + 1) & 07777;
break;
case 2: /* SNL */
if (LAC >= 010000)
PC = (PC + 1) & 07777;
break;
case 3: /* SZL */
if (LAC < 010000)
PC = (PC + 1) & 07777;
break;
case 4: /* SZA */
if ((LAC & 07777) == 0)
PC = (PC + 1) & 07777;
break;
case 5: /* SNA */
if ((LAC & 07777)
!= 0) PC = (PC + 1) & 07777;
break;
case 6: /* SZA | SNL */
if ((LAC == 0) || (LAC >= 010000))
PC = (PC + 1) & 07777;
break;
case 7: /* SNA & SZL */
if ((LAC != 0) && (LAC < 010000))
PC = (PC + 1) & 07777;
break;
case 010: /* SMA */
if ((LAC & 04000) != 0)
PC = (PC + 1) & 07777;
break;
case 011: /* SPA */
if ((LAC & 04000) == 0)
PC = (PC + 1) & 07777;
break;
case 012: /* SMA | SNL */
if (LAC >= 04000)
PC = (PC + 1) & 07777;
break;
case 013: /* SPA & SZL */
if (LAC < 04000)
PC = (PC + 1) & 07777;
break;
case 014: /* SMA | SZA */
if (((LAC & 04000) != 0) || ((LAC & 07777) == 0))
PC = (PC + 1) & 07777;
break;
case 015: /* SPA & SNA */
if (((LAC & 04000) == 0) && ((LAC & 07777) != 0))
PC = (PC + 1) & 07777;
break;
case 016: /* SMA | SZA | SNL */
if ((LAC >= 04000) || (LAC == 0))
PC = (PC + 1) & 07777;
break;
case 017: /* SPA & SNA & SZL */
if ((LAC < 04000) && (LAC != 0))
PC = (PC + 1) & 07777;
break;
} /* end switch skips */
if (IR & 0200) /* CLA */
LAC = LAC & 010000;
if ((IR & 06) && UF) { /* user mode? */
int_req = int_req | INT_UF; /* request intr */
tsc_ir = IR; /* save instruction */
tsc_cdf = 0; /* clear flag */
}
else {
if (IR & 04) /* OSR */
LAC = LAC | SR;
if (IR & 02) /* HLT */
reason = STOP_HALT;
}
break;
} /* end if group 2 */
/* OPR group 3 standard
MQA!MQL exchanges AC and MQ, as follows:
temp = MQ;
MQ = LAC & 07777;
LAC = LAC & 010000 | temp;
*/
temp = MQ; /* group 3 */
if (IR & 0200) /* CLA */
LAC = LAC & 010000;
if (IR & 0020) { /* MQL */
MQ = LAC & 07777;
LAC = LAC & 010000;
}
if (IR & 0100) /* MQA */
LAC = LAC | temp;
if ((IR & 0056) && (cpu_unit.flags & UNIT_NOEAE)) {
reason = stop_inst; /* EAE not present */
break;
}
/* OPR group 3 EAE
The EAE operates in two modes:
Mode A, PDP-8/I compatible
Mode B, extended capability
Mode B provides eight additional subfunctions; in addition, some
of the Mode A functions operate differently in Mode B.
The mode switch instructions are decoded explicitly and cannot be
microprogrammed with other EAE functions (SWAB performs an MQL as
part of standard group 3 decoding). If mode switching is decoded,
all other EAE timing is suppressed.
*/
if (IR == 07431) { /* SWAB */
emode = 1; /* set mode flag */
break;
}
if (IR == 07447) { /* SWBA */
emode = gtf = 0; /* clear mode, gtf */
break;
}
/* If not switching modes, the EAE operation is determined by the mode
and IR<6,8:10>:
<6:10> mode A mode B comments
0x000 NOP NOP
0x001 SCL ACS
0x010 MUY MUY if mode B, next = address
0x011 DVI DVI if mode B, next = address
0x100 NMI NMI if mode B, clear AC if
result = 4000'0000
0x101 SHL SHL if mode A, extra shift
0x110 ASR ASR if mode A, extra shift
0x111 LSR LSR if mode A, extra shift
1x000 SCA SCA
1x001 SCA + SCL DAD
1x010 SCA + MUY DST
1x011 SCA + DVI SWBA NOP if not detected earlier
1x100 SCA + NMI DPSZ
1x101 SCA + SHL DPIC must be combined with MQA!MQL
1x110 SCA + ASR DCM must be combined with MQA!MQL
1x111 SCA + LSR SAM
EAE instructions which fetch memory operands use the CPU's DEFER
state to read the first word; if the address operand is in locations
x0010 - x0017, it is autoincremented.
*/
if (emode == 0) /* mode A? clr gtf */
gtf = 0;
switch ((IR >> 1) & 027) { /* decode IR<6,8:10> */
case 020: /* mode A, B: SCA */
LAC = LAC | SC;
break;
case 000: /* mode A, B: NOP */
break;
case 021: /* mode B: DAD */
if (emode) {
MA = IF | PC;
if ((MA & 07770) != 00010) /* indirect; autoinc? */
MA = DF | M[MA];
else MA = DF | (M[MA] = (M[MA] + 1) & 07777); /* incr before use */
MQ = MQ + M[MA];
MA = DF | ((MA + 1) & 07777);
LAC = (LAC & 07777) + M[MA] + (MQ >> 12);
MQ = MQ & 07777;
PC = (PC + 1) & 07777;
break;
}
LAC = LAC | SC; /* mode A: SCA then */
case 001: /* mode B: ACS */
if (emode) {
SC = LAC & 037;
LAC = LAC & 010000;
}
else { /* mode A: SCL */
SC = (~M[IF | PC]) & 037;
PC = (PC + 1) & 07777;
}
break;
case 022: /* mode B: DST */
if (emode) {
MA = IF | PC;
if ((MA & 07770) != 00010) /* indirect; autoinc? */
MA = DF | M[MA];
else MA = DF | (M[MA] = (M[MA] + 1) & 07777); /* incr before use */
if (MEM_ADDR_OK (MA))
M[MA] = MQ & 07777;
MA = DF | ((MA + 1) & 07777);
if (MEM_ADDR_OK (MA))
M[MA] = LAC & 07777;
PC = (PC + 1) & 07777;
break;
}
LAC = LAC | SC; /* mode A: SCA then */
case 002: /* MUY */
MA = IF | PC;
if (emode) { /* mode B: defer */
if ((MA & 07770) != 00010) /* indirect; autoinc? */
MA = DF | M[MA];
else MA = DF | (M[MA] = (M[MA] + 1) & 07777); /* incr before use */
}
temp = (MQ * M[MA]) + (LAC & 07777);
LAC = (temp >> 12) & 07777;
MQ = temp & 07777;
PC = (PC + 1) & 07777;
SC = 014; /* 12 shifts */
break;
case 023: /* mode B: SWBA */
if (emode)
break;
LAC = LAC | SC; /* mode A: SCA then */
case 003: /* DVI */
MA = IF | PC;
if (emode) { /* mode B: defer */
if ((MA & 07770) != 00010) /* indirect; autoinc? */
MA = DF | M[MA];
else MA = DF | (M[MA] = (M[MA] + 1) & 07777); /* incr before use */
}
if ((LAC & 07777) >= M[MA]) { /* overflow? */
LAC = LAC | 010000; /* set link */
MQ = ((MQ << 1) + 1) & 07777; /* rotate MQ */
SC = 0; /* no shifts */
}
else {
temp = ((LAC & 07777) << 12) | MQ;
MQ = temp / M[MA];
LAC = temp % M[MA];
SC = 015; /* 13 shifts */
}
PC = (PC + 1) & 07777;
break;
case 024: /* mode B: DPSZ */
if (emode) {
if (((LAC | MQ) & 07777) == 0)
PC = (PC + 1) & 07777;
break;
}
LAC = LAC | SC; /* mode A: SCA then */
case 004: /* NMI */
temp = (LAC << 12) | MQ; /* preserve link */
for (SC = 0; ((temp & 017777777) != 0) &&
(temp & 040000000) == ((temp << 1) & 040000000); SC++)
temp = temp << 1;
LAC = (temp >> 12) & 017777;
MQ = temp & 07777;
if (emode && ((LAC & 07777) == 04000) && (MQ == 0))
LAC = LAC & 010000; /* clr if 4000'0000 */
break;
case 025: /* mode B: DPIC */
if (emode) {
temp = (LAC + 1) & 07777; /* SWP already done! */
LAC = MQ + (temp == 0);
MQ = temp;
break;
}
LAC = LAC | SC; /* mode A: SCA then */
case 5: /* SHL */
SC = (M[IF | PC] & 037) + (emode ^ 1); /* shift+1 if mode A */
if (SC > 25) /* >25? result = 0 */
temp = 0;
else temp = ((LAC << 12) | MQ) << SC; /* <=25? shift LAC:MQ */
LAC = (temp >> 12) & 017777;
MQ = temp & 07777;
PC = (PC + 1) & 07777;
SC = emode? 037: 0; /* SC = 0 if mode A */
break;
case 026: /* mode B: DCM */
if (emode) {
temp = (-LAC) & 07777; /* SWP already done! */
LAC = (MQ ^ 07777) + (temp == 0);
MQ = temp;
break;
}
LAC = LAC | SC; /* mode A: SCA then */
case 6: /* ASR */
SC = (M[IF | PC] & 037) + (emode ^ 1); /* shift+1 if mode A */
temp = ((LAC & 07777) << 12) | MQ; /* sext from AC0 */
if (LAC & 04000)
temp = temp | ~037777777;
if (emode && (SC != 0))
gtf = (temp >> (SC - 1)) & 1;
if (SC > 25)
temp = (LAC & 04000)? -1: 0;
else temp = temp >> SC;
LAC = (temp >> 12) & 017777;
MQ = temp & 07777;
PC = (PC + 1) & 07777;
SC = emode? 037: 0; /* SC = 0 if mode A */
break;
case 027: /* mode B: SAM */
if (emode) {
temp = LAC & 07777;
LAC = MQ + (temp ^ 07777) + 1; /* L'AC = MQ - AC */
gtf = (temp <= MQ) ^ ((temp ^ MQ) >> 11);
break;
}
LAC = LAC | SC; /* mode A: SCA then */
case 7: /* LSR */
SC = (M[IF | PC] & 037) + (emode ^ 1); /* shift+1 if mode A */
temp = ((LAC & 07777) << 12) | MQ; /* clear link */
if (emode && (SC != 0))
gtf = (temp >> (SC - 1)) & 1;
if (SC > 24) /* >24? result = 0 */
temp = 0;
else temp = temp >> SC; /* <=24? shift AC:MQ */
LAC = (temp >> 12) & 07777;
MQ = temp & 07777;
PC = (PC + 1) & 07777;
SC = emode? 037: 0; /* SC = 0 if mode A */
break;
} /* end switch */
break; /* end case 7 */
/* Opcode 6, IOT. From Bernhard Baehr's description of the TSC8-75:
(In user mode) Additional to raising a user mode interrupt, the current IOT
opcode is moved to the ERIOT register. When the IOT is a CDF instruction (62x1),
the ECDF flag is set, otherwise it is cleared. */
case 030:case 031:case 032:case 033: /* IOT */
if (UF) { /* privileged? */
int_req = int_req | INT_UF; /* request intr */
tsc_ir = IR; /* save instruction */
if ((IR & 07707) == 06201) /* set/clear flag */
tsc_cdf = 1;
else tsc_cdf = 0;
break;
}
device = (IR >> 3) & 077; /* device = IR<3:8> */
pulse = IR & 07; /* pulse = IR<9:11> */
iot_data = LAC & 07777; /* AC unchanged */
switch (device) { /* decode IR<3:8> */
case 000: /* CPU control */
switch (pulse) { /* decode IR<9:11> */
case 0: /* SKON */
if (int_req & INT_ION)
PC = (PC + 1) & 07777;
int_req = int_req & ~INT_ION;
break;
case 1: /* ION */
int_req = (int_req | INT_ION) & ~INT_NO_ION_PENDING;
break;
case 2: /* IOF */
int_req = int_req & ~INT_ION;
break;
case 3: /* SRQ */
if (int_req & INT_ALL)
PC = (PC + 1) & 07777;
break;
case 4: /* GTF */
LAC = (LAC & 010000) |
((LAC & 010000) >> 1) | (gtf << 10) |
(((int_req & INT_ALL) != 0) << 9) |
(((int_req & INT_ION) != 0) << 7) | SF;
break;
case 5: /* RTF */
gtf = ((LAC & 02000) >> 10);
UB = (LAC & 0100) >> 6;
IB = (LAC & 0070) << 9;
DF = (LAC & 0007) << 12;
LAC = ((LAC & 04000) << 1) | iot_data;
int_req = (int_req | INT_ION) & ~INT_NO_CIF_PENDING;
break;
case 6: /* SGT */
if (gtf)
PC = (PC + 1) & 07777;
break;
case 7: /* CAF */
gtf = 0;
emode = 0;
int_req = int_req & INT_NO_CIF_PENDING;
dev_done = 0;
int_enable = INT_INIT_ENABLE;
LAC = 0;
reset_all (1); /* reset all dev */
break;
} /* end switch pulse */
break; /* end case 0 */
case 020:case 021:case 022:case 023:
case 024:case 025:case 026:case 027: /* memory extension */
switch (pulse) { /* decode IR<9:11> */
case 1: /* CDF */
DF = (IR & 0070) << 9;
break;
case 2: /* CIF */
IB = (IR & 0070) << 9;
int_req = int_req & ~INT_NO_CIF_PENDING;
break;
case 3: /* CDF CIF */
DF = IB = (IR & 0070) << 9;
int_req = int_req & ~INT_NO_CIF_PENDING;
break;
case 4:
switch (device & 07) { /* decode IR<6:8> */
case 0: /* CINT */
int_req = int_req & ~INT_UF;
break;
case 1: /* RDF */
LAC = LAC | (DF >> 9);
break;
case 2: /* RIF */
LAC = LAC | (IF >> 9);
break;
case 3: /* RIB */
LAC = LAC | SF;
break;
case 4: /* RMF */
UB = (SF & 0100) >> 6;
IB = (SF & 0070) << 9;
DF = (SF & 0007) << 12;
int_req = int_req & ~INT_NO_CIF_PENDING;
break;
case 5: /* SINT */
if (int_req & INT_UF)
PC = (PC + 1) & 07777;
break;
case 6: /* CUF */
UB = 0;
int_req = int_req & ~INT_NO_CIF_PENDING;
break;
case 7: /* SUF */
UB = 1;
int_req = int_req & ~INT_NO_CIF_PENDING;
break;
} /* end switch device */
break;
default:
reason = stop_inst;
break;
} /* end switch pulse */
break; /* end case 20-27 */
case 010: /* power fail */
switch (pulse) { /* decode IR<9:11> */
case 1: /* SBE */
break;
case 2: /* SPL */
if (int_req & INT_PWR)
PC = (PC + 1) & 07777;
break;
case 3: /* CAL */
int_req = int_req & ~INT_PWR;
break;
default:
reason = stop_inst;
break;
} /* end switch pulse */
break; /* end case 10 */
default: /* I/O device */
if (dev_tab[device]) { /* dev present? */
iot_data = dev_tab[device] (IR, iot_data);
LAC = (LAC & 010000) | (iot_data & 07777);
if (iot_data & IOT_SKP)
PC = (PC + 1) & 07777;
if (iot_data >= IOT_REASON)
reason = iot_data >> IOT_V_REASON;
}
else reason = stop_inst; /* stop on flag */
break;
} /* end switch device */
break; /* end case IOT */
} /* end switch opcode */
} /* end while */
/* Simulation halted */
saved_PC = IF | (PC & 07777); /* save copies */
saved_DF = DF & 070000;
saved_LAC = LAC & 017777;
saved_MQ = MQ & 07777;
pcq_r->qptr = pcq_p; /* update pc q ptr */
return reason;
} /* end sim_instr */
/* Reset routine */
t_stat cpu_reset (DEVICE *dptr)
{
saved_LAC = 0;
int_req = (int_req & ~INT_ION) | INT_NO_CIF_PENDING;
saved_DF = IB = saved_PC & 070000;
UF = UB = gtf = emode = 0;
pcq_r = find_reg ("PCQ", NULL, dptr);
if (pcq_r)
pcq_r->qptr = 0;
else return SCPE_IERR;
sim_brk_types = SWMASK ('E') | SWMASK('I');
sim_brk_dflt = SWMASK ('E');
return SCPE_OK;
}
/* Set PC for boot (PC<14:12> will typically be 0) */
void cpu_set_bootpc (int32 pc)
{
saved_PC = pc; /* set PC, IF */
saved_DF = IB = pc & 070000; /* set IB, DF */
return;
}
/* Memory examine */
t_stat cpu_ex (t_value *vptr, t_addr addr, UNIT *uptr, int32 sw)
{
if (addr >= MEMSIZE)
return SCPE_NXM;
if (vptr != NULL)
*vptr = M[addr] & 07777;
return SCPE_OK;
}
/* Memory deposit */
t_stat cpu_dep (t_value val, t_addr addr, UNIT *uptr, int32 sw)
{
if (addr >= MEMSIZE)
return SCPE_NXM;
M[addr] = val & 07777;
return SCPE_OK;
}
/* Memory size change */
t_stat cpu_set_size (UNIT *uptr, int32 val, CONST char *cptr, void *desc)
{
int32 mc = 0;
uint32 i;
if ((val <= 0) || (val > MAXMEMSIZE) || ((val & 07777) != 0))
return SCPE_ARG;
for (i = val; i < MEMSIZE; i++)
mc = mc | M[i];
if ((mc != 0) && (!get_yn ("Really truncate memory [N]?", FALSE)))
return SCPE_OK;
MEMSIZE = val;
for (i = MEMSIZE; i < MAXMEMSIZE; i++)
M[i] = 0;
return SCPE_OK;
}
/* Change device number for a device */
t_stat set_dev (UNIT *uptr, int32 val, CONST char *cptr, void *desc)
{
DEVICE *dptr;
DIB *dibp;
uint32 newdev;
t_stat r;
if (cptr == NULL)
return SCPE_ARG;
if (uptr == NULL)
return SCPE_IERR;
dptr = find_dev_from_unit (uptr);
if (dptr == NULL)
return SCPE_IERR;
dibp = (DIB *) dptr->ctxt;
if (dibp == NULL)
return SCPE_IERR;
newdev = get_uint (cptr, 8, DEV_MAX - 1, &r); /* get new */
if ((r != SCPE_OK) || (newdev == dibp->dev))
return r;
dibp->dev = newdev; /* store */
return SCPE_OK;
}
/* Show device number for a device */
t_stat show_dev (FILE *st, UNIT *uptr, int32 val, CONST void *desc)
{
DEVICE *dptr;
DIB *dibp;
if (uptr == NULL)
return SCPE_IERR;
dptr = find_dev_from_unit (uptr);
if (dptr == NULL)
return SCPE_IERR;
dibp = (DIB *) dptr->ctxt;
if (dibp == NULL)
return SCPE_IERR;
fprintf (st, "devno=%02o", dibp->dev);
if (dibp->num > 1)
fprintf (st, "-%2o", dibp->dev + dibp->num - 1);
return SCPE_OK;
}
/* CPU device handler - should never get here! */
int32 bad_dev (int32 IR, int32 AC)
{
return (SCPE_IERR << IOT_V_REASON) | AC; /* broken! */
}
/* Build device dispatch table */
t_bool build_dev_tab (void)
{
DEVICE *dptr;
DIB *dibp;
uint32 i, j;
static const uint8 std_dev[] = {
000, 010, 020, 021, 022, 023, 024, 025, 026, 027
};
for (i = 0; i < DEV_MAX; i++) /* clr table */
dev_tab[i] = NULL;
for (i = 0; i < ((uint32) sizeof (std_dev)); i++) /* std entries */
dev_tab[std_dev[i]] = &bad_dev;
for (i = 0; (dptr = sim_devices[i]) != NULL; i++) { /* add devices */
dibp = (DIB *) dptr->ctxt; /* get DIB */
if (dibp && !(dptr->flags & DEV_DIS)) { /* enabled? */
if (dibp->dsp_tbl) { /* dispatch table? */
DIB_DSP *dspp = dibp->dsp_tbl; /* set ptr */
for (j = 0; j < dibp->num; j++, dspp++) { /* loop thru tbl */
if (dspp->dsp) { /* any dispatch? */
if (dev_tab[dspp->dev]) { /* already filled? */
sim_printf ("%s device number conflict at %02o\n",
sim_dname (dptr), dibp->dev + j);
return TRUE;
}
dev_tab[dspp->dev] = dspp->dsp; /* fill */
} /* end if dsp */
} /* end for j */
} /* end if dsp_tbl */
else { /* inline dispatches */
for (j = 0; j < dibp->num; j++) { /* loop thru disp */
if (dibp->dsp[j]) { /* any dispatch? */
if (dev_tab[dibp->dev + j]) { /* already filled? */
sim_printf ("%s device number conflict at %02o\n",
sim_dname (dptr), dibp->dev + j);
return TRUE;
}
dev_tab[dibp->dev + j] = dibp->dsp[j]; /* fill */
} /* end if dsp */
} /* end for j */
} /* end else */
} /* end if enb */
} /* end for i */
return FALSE;
}
/* Set history */
t_stat cpu_set_hist (UNIT *uptr, int32 val, CONST char *cptr, void *desc)
{
int32 i, lnt;
t_stat r;
if (cptr == NULL) {
for (i = 0; i < hst_lnt; i++)
hst[i].pc = 0;
hst_p = 0;
return SCPE_OK;
}
lnt = (int32) get_uint (cptr, 10, HIST_MAX, &r);
if ((r != SCPE_OK) || (lnt && (lnt < HIST_MIN)))
return SCPE_ARG;
hst_p = 0;
if (hst_lnt) {
free (hst);
hst_lnt = 0;
hst = NULL;
}
if (lnt) {
hst = (InstHistory *) calloc (lnt, sizeof (InstHistory));
if (hst == NULL)
return SCPE_MEM;
hst_lnt = lnt;
}
return SCPE_OK;
}
/* Show history */
t_stat cpu_show_hist (FILE *st, UNIT *uptr, int32 val, CONST void *desc)
{
int32 l, k, di, lnt;
const char *cptr = (const char *) desc;
t_stat r;
InstHistory *h;
if (hst_lnt == 0) /* enabled? */
return SCPE_NOFNC;
if (cptr) {
lnt = (int32) get_uint (cptr, 10, hst_lnt, &r);
if ((r != SCPE_OK) || (lnt == 0))
return SCPE_ARG;
}
else lnt = hst_lnt;
di = hst_p - lnt; /* work forward */
if (di < 0)
di = di + hst_lnt;
fprintf (st, "PC L AC MQ ea IR\n\n");
for (k = 0; k < lnt; k++) { /* print specified */
h = &hst[(++di) % hst_lnt]; /* entry pointer */
if (h->pc & HIST_PC) { /* instruction? */
l = (h->lac >> 12) & 1; /* link */
fprintf (st, "%05o %o %04o %04o ", h->pc & ADDRMASK, l, h->lac & 07777, h->mq);
if (h->ir < 06000)
fprintf (st, "%05o ", h->ea);
else fprintf (st, " ");
sim_eval[0] = h->ir;
if ((fprint_sym (st, h->pc & ADDRMASK, sim_eval, &cpu_unit, SWMASK ('M'))) > 0)
fprintf (st, "(undefined) %04o", h->ir);
if (h->ir < 04000)
fprintf (st, " [%04o]", h->opnd);
fputc ('\n', st); /* end line */
} /* end else instruction */
} /* end for */
return SCPE_OK;
}