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/* pdp18b_cpu.c: 18b PDP CPU simulator
Copyright (c) 1993-2002, 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 PDP-4/7/9/15 central processor
05-Oct-02 RMS Added DIBs, device number support
25-Jul-02 RMS Added DECtape support for PDP-4
06-Jan-02 RMS Revised enable/disable support
30-Dec-01 RMS Added old PC queue
30-Nov-01 RMS Added extended SET/SHOW support
25-Nov-01 RMS Revised interrupt structure
19-Sep-01 RMS Fixed bug in EAE (found by Dave Conroy)
17-Sep-01 RMS Fixed typo in conditional
10-Aug-01 RMS Removed register from declarations
17-Jul-01 RMS Moved function prototype
27-May-01 RMS Added second Teletype support, fixed bug in API
18-May-01 RMS Added PDP-9,-15 API option
16-May-01 RMS Fixed bugs in protection checks
26-Apr-01 RMS Added device enable/disable support
25-Jan-01 RMS Added DECtape support
18-Dec-00 RMS Added PDP-9,-15 memm init register
30-Nov-00 RMS Fixed numerous PDP-15 bugs
14-Apr-99 RMS Changed t_addr to unsigned
The 18b PDP family has five distinct architectural variants: PDP-1,
PDP-4, PDP-7, PDP-9, and PDP-15. Of these, the PDP-1 is so unique
as to require a different simulator. The PDP-4, PDP-7, PDP-9, and
PDP-15 are "upward compatible", with each new variant adding
distinct architectural features and incompatibilities.
The register state for the 18b PDP's is:
all AC<0:17> accumulator
all MQ<0:17> multiplier-quotient
all L link flag
all PC<0:x> program counter
all IORS I/O status register
PDP-7, PDP-9 EXTM extend mode
PDP-15 BANKM bank mode
PDP-7 USMD trap mode
PDP-9, PDP-15 USMD user mode
PDP-9, PDP-15 BR bounds register
PDP-15 XR index register
PDP-15 LR limit register
*/
/* The PDP-4, PDP-7, and PDP-9 have five instruction formats: memory
reference, load immediate, I/O transfer, EAE, and operate. The PDP-15
adds a sixth, index operate, and a seventh, floating point. The memory
reference format for the PDP-4, PDP-7, and PDP-9, and for the PDP-15
in bank mode, is:
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| op |in| address | memory reference
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
The PDP-15 in page mode trades an address bit for indexing capability:
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| op |in| X| address | memory reference
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
<0:3> mnemonic action
00 CAL JMS with MA = 20
04 DAC M[MA] = AC
10 JMS M[MA] = L'mem'user'PC, PC = MA + 1
14 DZM M[MA] = 0
20 LAC AC = M[MA]
24 XOR AC = AC ^ M[MA]
30 ADD L'AC = AC + M[MA] one's complement
34 TAD L'AC = AC + M[MA]
40 XCT M[MA] is executed as an instruction
44 ISZ M[MA] = M[MA] + 1, skip if M[MA] == 0
50 AND AC = AC & M[MA]
54 SAD skip if AC != M[MA]
60 JMP PC = MA
On the PDP-4, PDP-7, and PDP-9, and the PDP-15 in bank mode, memory
reference instructions can access an address space of 32K words. The
address space is divided into four 8K word fields. An instruction can
directly address, via its 13b address, the entire current field. On the
PDP-4, PDP-7, and PDP-9, if extend mode is off, indirect addresses access
the current field; if on (or a PDP-15), they can access all 32K.
On the PDP-15 in page mode, memory reference instructions can access
an address space of 128K words. The address is divided into four 32K
word blocks, each of which consists of eight 4K pages. An instruction
can directly address, via its 12b address, the current page. Indirect
addresses can access the current block. Indexed and autoincrement
addresses can access all 128K.
On the PDP-4 and PDP-7, if an indirect address in in locations 00010-
00017 of any field, the indirect address is incremented and rewritten
to memory before use. On the PDP-9 and PDP-15, only locations 00010-
00017 of field zero autoincrement; special logic will redirect indirect
references to 00010-00017 to field zero, even if (on the PDP-9) extend
mode is off.
*/
/* The EAE format is:
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| 1 1 0 1| | | | | | | | | | | | | | | EAE
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| | | | | | | | | | | | | |
| | | | | | | | | | | | | +- or SC (3)
| | | | | | | | | | | | +---- or MQ (3)
| | | | | | | | | | | +------- compl MQ (3)
| | | | | | | | \______________/
| | | | | | | | |
| | | | | \_____/ +--------- shift count
| | | | | |
| | | | | +---------------------- EAE command (3)
| | | | +---------------------------- clear AC (2)
| | | +------------------------------- or AC (2)
| | +---------------------------------- load EAE sign (1)
| +------------------------------------- clear MQ (1)
+---------------------------------------- load link (1)
The I/O transfer format is:
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| 1 1 1 0 0 0| device | sdv |cl| pulse | I/O transfer
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
The IO transfer instruction sends the the specified pulse to the
specified I/O device and sub-device. The I/O device may take data
from the AC, return data to the AC, initiate or cancel operations,
or skip on status. On the PDP-4, PDP-7, and PDP-9, bits <4:5>
were designated as subdevice bits but were never used; the PDP-15
requires them to be zero.
On the PDP-15, the floating point format is:
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| 1 1 1 0 0 1| subopcode | floating point
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
|in| address |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
Indirection is always single level.
*/
/* On the PDP-15, the index operate format is:
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| 1 1 1 0 1| subopcode | immediate | index operate
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
The index operate instructions provide various operations on the
index and limit registers.
The operate format is:
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| 1 1 1 1 0| | | | | | | | | | | | | | operate
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| | | | | | | | | | | | |
| | | | | | | | | | | | +- CMA (3)
| | | | | | | | | | | +---- CML (3)
| | | | | | | | | | +------- OAS (3)
| | | | | | | | | +---------- RAL (3)
| | | | | | | | +------------- RAR (3)
| | | | | | | +---------------- HLT (4)
| | | | | | +------------------- SMA (1)
| | | | | +---------------------- SZA (1)
| | | | +------------------------- SNL (1)
| | | +---------------------------- invert skip (1)
| | +------------------------------- rotate twice (2)
| +---------------------------------- CLL (2)
+------------------------------------- CLA (2)
The operate instruction can be microprogrammed to perform operations
on the AC and link.
The load immediate format is:
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| 1 1 1 1 1| immediate | LAW
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
<0:4> mnemonic action
76 LAW AC = IR
*/
/* This routine is the instruction decode routine for the 18b PDP's.
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
nested XCT's
I/O error in I/O simulator
2. Interrupts. Interrupt requests are maintained in the int_hwre
array. int_hwre[0:3] corresponds to API levels 0-3; int_hwre[4]
holds PI requests.
3. Arithmetic. The 18b PDP's implements both 1's and 2's complement
arithmetic for signed numbers. In 1's complement arithmetic, a
negative number is represented by the complement (XOR 0777777) of
its absolute value. Addition of 1's complement numbers requires
propagating the carry out of the high order bit back to the low
order bit.
4. Adding I/O devices. Three modules must be modified:
pdp18b_defs.h add interrupt request definition
pdp18b_sys.c add sim_devices table entry
*/
#include "pdp18b_defs.h"
#define PCQ_SIZE 64 /* must be 2**n */
#define PCQ_MASK (PCQ_SIZE - 1)
#define PCQ_ENTRY pcq[pcq_p = (pcq_p - 1) & PCQ_MASK] = PC
#define UNIT_V_NOEAE (UNIT_V_UF) /* EAE absent */
#define UNIT_V_NOAPI (UNIT_V_UF+1) /* API absent */
#define UNIT_V_MSIZE (UNIT_V_UF+2) /* dummy mask */
#define UNIT_NOEAE (1 << UNIT_V_NOEAE)
#define UNIT_NOAPI (1 << UNIT_V_NOAPI)
#define UNIT_MSIZE (1 << UNIT_V_MSIZE)
#if defined (PDP4)
#define EAE_DFLT UNIT_NOEAE
#else
#define EAE_DFLT 0
#endif
#if defined (PDP4) || defined (PDP7)
#define API_DFLT UNIT_NOAPI
#else
#define API_DFLT UNIT_NOAPI /* for now */
#endif
int32 M[MAXMEMSIZE] = { 0 }; /* memory */
int32 saved_LAC = 0; /* link'AC */
int32 saved_MQ = 0; /* MQ */
int32 saved_PC = 0; /* PC */
int32 iors = 0; /* IORS */
int32 ion = 0; /* int on */
int32 ion_defer = 0; /* int defer */
int32 int_pend = 0; /* int pending */
int32 int_hwre[API_HLVL+1] = { 0 }; /* int requests */
int32 api_enb = 0; /* API enable */
int32 api_req = 0; /* API requests */
int32 api_act = 0; /* API active */
int32 memm = 0; /* mem mode */
#if defined (PDP15)
int32 memm_init = 1; /* mem init */
#else
int32 memm_init = 0;
#endif
int32 usmd = 0; /* user mode */
int32 usmdbuf = 0; /* user mode buffer */
int32 trap_pending = 0; /* trap pending */
int32 emir_pending = 0; /* emir pending */
int32 rest_pending = 0; /* restore pending */
int32 BR = 0; /* mem mgt bounds */
int32 nexm = 0; /* nx mem flag */
int32 prvn = 0; /* priv viol flag */
int32 SC = 0; /* shift count */
int32 eae_ac_sign = 0; /* EAE AC sign */
int32 SR = 0; /* switch register */
int32 XR = 0; /* index register */
int32 LR = 0; /* limit register */
int32 stop_inst = 0; /* stop on rsrv inst */
int32 xct_max = 16; /* nested XCT limit */
#if defined (PDP15)
int32 pcq[PCQ_SIZE] = { 0 }; /* PC queue */
#else
int16 pcq[PCQ_SIZE] = { 0 }; /* PC queue */
#endif
int32 pcq_p = 0; /* PC queue ptr */
REG *pcq_r = NULL; /* PC queue reg ptr */
extern int32 sim_int_char;
extern int32 sim_interval;
extern int32 sim_brk_types, sim_brk_dflt, sim_brk_summ; /* breakpoint info */
extern DEVICE *sim_devices[];
extern FILE *sim_log;
t_bool build_dev_tab (void);
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, char *cptr, void *desc);
int32 upd_iors (void);
int32 api_eval (int32 *pend);
extern clk (int32 pulse, int32 AC);
int32 (*dev_tab[DEV_MAX])(int32 pulse, int32 AC); /* device dispatch */
int32 (*dev_iors[DEV_MAX])(void); /* IORS dispatch */
static const int32 api_ffo[256] = {
8, 7, 6, 6, 5, 5, 5, 5, 4, 4, 4, 4, 4, 4, 4, 4,
3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
static const int32 api_vec[API_HLVL][32] = {
{ ACH_PWRFL }, /* API 0 */
{ ACH_DTA, ACH_MTA, ACH_DRM, ACH_RF, ACH_RP }, /* API 1 */
{ ACH_PTR, ACH_LPT, ACH_LPT }, /* API 2 */
{ ACH_CLK, ACH_TTI1, ACH_TTO1 } }; /* API 3 */
/* CPU data structures
cpu_dev CPU device descriptor
cpu_unit CPU unit
cpu_reg CPU register list
cpu_mod CPU modifier list
*/
UNIT cpu_unit = { UDATA (NULL, UNIT_FIX + UNIT_BINK + EAE_DFLT + API_DFLT,
MAXMEMSIZE) };
REG cpu_reg[] = {
{ ORDATA (PC, saved_PC, ADDRSIZE) },
{ ORDATA (AC, saved_LAC, 18) },
{ FLDATA (L, saved_LAC, 18) },
#if !defined (PDP4)
{ ORDATA (MQ, saved_MQ, 18) },
{ ORDATA (SC, SC, 6) },
{ FLDATA (EAE_AC_SIGN, eae_ac_sign, 18) },
#endif
{ ORDATA (SR, SR, 18) },
{ ORDATA (IORS, iors, 18), REG_RO },
{ BRDATA (INT, int_hwre, 8, 32, API_HLVL+1), REG_RO },
{ FLDATA (ION, ion, 0) },
{ ORDATA (ION_DELAY, ion_defer, 2) },
#if defined (PDP7)
{ FLDATA (TRAPM, usmd, 0) },
{ FLDATA (TRAPP, trap_pending, 0) },
{ FLDATA (EXTM, memm, 0) },
{ FLDATA (EXTM_INIT, memm_init, 0) },
{ FLDATA (EMIRP, emir_pending, 0) },
#endif
#if defined (PDP9)
{ FLDATA (APIENB, api_enb, 0) },
{ ORDATA (APIREQ, api_req, 8) },
{ ORDATA (APIACT, api_act, 8) },
{ ORDATA (BR, BR, ADDRSIZE) },
{ FLDATA (USMD, usmd, 0) },
{ FLDATA (USMDBUF, usmdbuf, 0) },
{ FLDATA (NEXM, nexm, 0) },
{ FLDATA (PRVN, prvn, 0) },
{ FLDATA (TRAPP, trap_pending, 0) },
{ FLDATA (EXTM, memm, 0) },
{ FLDATA (EXTM_INIT, memm_init, 0) },
{ FLDATA (EMIRP, emir_pending, 0) },
{ FLDATA (RESTP, rest_pending, 0) },
{ FLDATA (PWRFL, int_hwre[API_PWRFL], INT_V_PWRFL) },
#endif
#if defined (PDP15)
{ FLDATA (APIENB, api_enb, 0) },
{ ORDATA (APIREQ, api_req, 8) },
{ ORDATA (APIACT, api_act, 8) },
{ ORDATA (XR, XR, 18) },
{ ORDATA (LR, LR, 18) },
{ ORDATA (BR, BR, ADDRSIZE) },
{ FLDATA (USMD, usmd, 0) },
{ FLDATA (USMDBUF, usmdbuf, 0) },
{ FLDATA (NEXM, nexm, 0) },
{ FLDATA (PRVN, prvn, 0) },
{ FLDATA (TRAPP, trap_pending, 0) },
{ FLDATA (BANKM, memm, 0) },
{ FLDATA (BANKM_INIT, memm_init, 0) },
{ FLDATA (RESTP, rest_pending, 0) },
{ FLDATA (PWRFL, int_hwre[API_PWRFL], INT_V_PWRFL) },
#endif
{ BRDATA (PCQ, pcq, 8, ADDRSIZE, PCQ_SIZE), REG_RO+REG_CIRC },
{ ORDATA (PCQP, pcq_p, 6), REG_HRO },
{ FLDATA (STOP_INST, stop_inst, 0) },
{ DRDATA (XCT_MAX, xct_max, 8), PV_LEFT + REG_NZ },
{ ORDATA (WRU, sim_int_char, 8) },
{ NULL } };
MTAB cpu_mod[] = {
#if !defined (PDP4)
{ UNIT_NOEAE, UNIT_NOEAE, "no EAE", "NOEAE", NULL },
{ UNIT_NOEAE, 0, "EAE", "EAE", NULL },
#else
{ UNIT_MSIZE, 4096, NULL, "4K", &cpu_set_size },
#endif
#if defined (PDP9) || defined (PDP15)
{ UNIT_NOAPI, UNIT_NOAPI, "no API", "NOAPI", NULL },
{ UNIT_NOAPI, 0, "API", "API", NULL },
#endif
{ UNIT_MSIZE, 8192, NULL, "8K", &cpu_set_size },
#if (MAXMEMSIZE > 8192)
{ 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 },
#endif
#if (MAXMEMSIZE > 32768)
{ UNIT_MSIZE, 49152, NULL, "48K", &cpu_set_size },
{ UNIT_MSIZE, 65536, NULL, "64K", &cpu_set_size },
{ UNIT_MSIZE, 81920, NULL, "80K", &cpu_set_size },
{ UNIT_MSIZE, 98304, NULL, "96K", &cpu_set_size },
{ UNIT_MSIZE, 114688, NULL, "112K", &cpu_set_size },
{ UNIT_MSIZE, 131072, NULL, "128K", &cpu_set_size },
#endif
{ 0 } };
DEVICE cpu_dev = {
"CPU", &cpu_unit, cpu_reg, cpu_mod,
1, 8, ADDRSIZE, 1, 8, 18,
&cpu_ex, &cpu_dep, &cpu_reset,
NULL, NULL, NULL };
t_stat sim_instr (void)
{
int32 PC, LAC, MQ;
int32 api_int, api_cycle, skp;
int32 iot_data, device, pulse;
t_stat reason;
extern UNIT clk_unit;
#define JMS_WORD(t) (((LAC & 01000000) >> 1) | ((memm & 1) << 16) | \
(((t) & 1) << 15) | ((PC) & 077777))
#define INCR_ADDR(x) (((x) & epcmask) | (((x) + 1) & damask))
#define SEXT(x) ((int) (((x) & 0400000)? (x) | ~0777777: (x) & 0777777))
/* The following macros implement addressing. They account for autoincrement
addressing, extended addressing, and memory protection, if it exists.
CHECK_AUTO_INC check auto increment
INDIRECT indirect addressing
CHECK_INDEX check indexing
CHECK_ADDR_R check address for read
CHECK_ADDR_W check address for write
On the PDP-4 and PDP-7,
There are autoincrement locations in every field. If a field
does not exist, it is impossible to generate an
autoincrement reference (all instructions are CAL).
Indirect addressing range is determined by extend mode.
There is no indexing.
There is no memory protection, nxm reads zero and ignores writes.
*/
#if defined (PDP4) || defined (PDP7)
#define CHECK_AUTO_INC \
if ((IR & 017770) == 010) M[MA] = (M[MA] + 1) & 0777777
#define INDIRECT \
MA = memm? M[MA] & IAMASK: (MA & epcmask) | (M[MA] & damask)
#define CHECK_INDEX /* no indexing capability */
#define CHECK_ADDR_R(x) /* no read protection */
#define CHECK_ADDR_W(x) \
if (!MEM_ADDR_OK (x)) break
#endif
/* On the PDP-9,
The autoincrement registers are in field zero only. Regardless
of extend mode, indirect addressing through 00010-00017
will access absolute locations 00010-00017.
Indirect addressing range is determined by extend mode. If
extend mode is off, and autoincrementing is used, the
resolved address is in bank 0 (KG09B maintenance manual).
There is no indexing.
Memory protection is implemented for foreground/background operation.
*/
#if defined (PDP9)
#define CHECK_AUTO_INC \
if ((IR & 017770) == 010) { \
MA = MA & 017; \
M[MA] = (M[MA] + 1) & 0777777; }
#define INDIRECT \
MA = memm? M[MA] & IAMASK: (MA & epcmask) | (M[MA] & damask)
#define CHECK_ADDR_R(x) \
if (usmd) { \
if (!MEM_ADDR_OK (x)) { \
nexm = prvn = trap_pending = 1; \
break; } \
if ((x) < BR) { \
prvn = trap_pending = 1; \
break; } } \
if (!MEM_ADDR_OK (x)) nexm = 1
#define CHECK_INDEX /* no indexing capability */
#define CHECK_ADDR_W(x) \
CHECK_ADDR_R (x); \
if (!MEM_ADDR_OK (x)) break
#endif
/* On the PDP-15,
The autoincrement registers are in page zero only. Regardless
of bank mode, indirect addressing through 00010-00017
will access absolute locations 00010-00017.
Indirect addressing range is determined by autoincrementing.
Indexing is available if bank mode is off.
Memory protection is implemented for foreground/background operation.
*/
#if defined (PDP15)
#define CHECK_AUTO_INC \
if ((IR & damask & ~07) == 00010) { \
MA = MA & 017; \
M[MA] = (M[MA] + 1) & 0777777; }
#define INDIRECT \
if (rest_pending) { \
rest_pending = 0; \
LAC = ((M[MA] << 1) & 01000000) | (LAC & 0777777); \
memm = (M[MA] >> 16) & 1; \
usmd = (M[MA] >> 15) & 1; } \
MA = ((IR & damask & ~07) != 00010)? \
(PC & BLKMASK) | (M[MA] & IAMASK): (M[MA] & ADDRMASK); \
damask = memm? 017777: 07777; \
epcmask = ADDRMASK & ~damask
#define CHECK_INDEX \
if ((IR & 0010000) && (memm == 0)) MA = (MA + XR) & ADDRMASK
#define CHECK_ADDR_R(x) \
if (usmd) { \
if (!MEM_ADDR_OK (x)) { \
nexm = prvn = trap_pending = 1; \
break; } \
if ((x) < BR) { \
prvn = trap_pending = 1; \
break; } } \
if (!MEM_ADDR_OK (x)) nexm = 1
#define CHECK_ADDR_W(x) \
CHECK_ADDR_R (x); \
if (!MEM_ADDR_OK (x)) break
#endif
/* Restore register state */
#if defined (PDP15)
int32 epcmask, damask;
damask = memm? 017777: 07777; /* set dir addr mask */
epcmask = ADDRMASK & ~damask; /* extended PC mask */
#else
#define damask 017777 /* direct addr mask */
#define epcmask (ADDRMASK & ~damask) /* extended PC mask */
#endif
if (build_dev_tab ()) return SCPE_STOP; /* build, chk tables */
PC = saved_PC & ADDRMASK; /* load local copies */
LAC = saved_LAC & 01777777;
MQ = saved_MQ & 0777777;
reason = 0;
sim_rtc_init (clk_unit.wait); /* init calibration */
if (cpu_unit.flags & UNIT_NOAPI) api_enb = api_req = api_act = 0;
api_int = api_eval (&int_pend); /* eval API */
api_cycle = 0; /* not API cycle */
/* Main instruction fetch/decode loop: check trap and interrupt */
while (reason == 0) { /* loop until halted */
int32 IR, MA, esc, t, xct_count;
int32 link_init, fill;
if (sim_interval <= 0) { /* check clock queue */
if (reason = sim_process_event ()) break;
api_int = api_eval (&int_pend); } /* eval API */
/* Protection traps work like interrupts, with these quirks:
PDP-7 extend mode forced on, M[0] = PC, PC = 2
PDP-9 extend mode ???, M[0/20] = PC, PC = 0/21
PDP-15 bank mode unchanged, M[0/20] = PC, PC = 0/21
*/
#if defined (PDP7)
if (trap_pending) { /* trap pending? */
PCQ_ENTRY; /* save old PC */
M[0] = JMS_WORD (1); /* save state */
PC = 2; /* fetch next from 2 */
ion = 0; /* interrupts off */
memm = 1; /* extend on */
emir_pending = trap_pending = 0; /* emir, trap off */
usmd = 0; } /* protect off */
#endif
#if defined (PDP9) || defined (PDP15)
if (trap_pending) { /* trap pending? */
PCQ_ENTRY; /* save old PC */
MA = ion? 0: 020; /* save in 0 or 20 */
M[MA] = JMS_WORD (1); /* save state */
PC = MA + 1; /* fetch next */
ion = 0; /* interrupts off */
emir_pending = rest_pending = trap_pending = 0; /* emir,rest,trap off */
usmd = 0; } /* protect off */
/* PDP-9 and PDP-15 automatic priority interrupt (API) */
if (api_int && !ion_defer) { /* API intr? */
int32 i, lvl = api_int - 1; /* get req level */
api_act = api_act | (0200 >> lvl); /* set level active */
if (lvl >= API_HLVL) { /* software req? */
MA = ACH_SWRE + lvl - API_HLVL; /* vec = 40:43 */
api_req = api_req & ~(0200 >> lvl); } /* remove request */
else {
MA = 0; /* assume fails */
for (i = 0; i < 32; i++) { /* loop hi to lo */
if ((int_hwre[lvl] >> i) & 1) { /* int req set? */
MA = api_vec[lvl][i]; /* get vector */
break; } } } /* and stop */
if (MA == 0) { /* bad channel? */
reason = STOP_API; /* API error */
break; }
api_int = api_eval (&int_pend); /* no API int */
api_cycle = 1; /* in API cycle */
emir_pending = rest_pending = 0; /* emir, restore off */
xct_count = 0;
goto xct_instr; }
/* Standard program interrupt */
if (!(api_enb && api_act) && ion && !ion_defer && int_pend) {
#else
if (ion && !ion_defer && int_pend) { /* interrupt? */
#endif
PCQ_ENTRY; /* save old PC */
M[0] = JMS_WORD (usmd); /* save state */
PC = 1; /* fetch next from 1 */
ion = 0; /* interrupts off */
#if !defined (PDP15) /* except PDP-15, */
memm = 0; /* extend off */
#endif
emir_pending = rest_pending = 0; /* emir, restore off */
usmd = 0; } /* protect off */
/* Breakpoint */
if (sim_brk_summ && sim_brk_test (PC, SWMASK ('E'))) { /* breakpoint? */
reason = STOP_IBKPT; /* stop simulation */
break; }
/* Fetch, decode instruction */
#if defined (PDP9) || defined (PDP15)
if (usmd) { /* user mode? */
if (!MEM_ADDR_OK (PC)) { /* nxm? */
nexm = prvn = trap_pending = 1; /* abort fetch */
continue; }
if (PC < BR) { /* bounds viol? */
prvn = trap_pending = 1; /* abort fetch */
continue; } }
else if (!MEM_ADDR_OK (PC)) nexm = 1; /* flag nxm */
if (!ion_defer) usmd = usmdbuf; /* no IOT? load usmd */
#endif
xct_count = 0; /* track nested XCT's */
MA = PC; /* fetch at PC */
PC = INCR_ADDR (PC); /* increment PC */
xct_instr: /* label for XCT */
IR = M[MA]; /* fetch instruction */
if (ion_defer) ion_defer = ion_defer - 1; /* count down defer */
if (sim_interval) sim_interval = sim_interval - 1;
MA = (MA & epcmask) | (IR & damask); /* effective address */
switch ((IR >> 13) & 037) { /* decode IR<0:4> */
/* LAC: opcode 20 */
case 011: /* LAC, indir */
CHECK_AUTO_INC;
INDIRECT;
case 010: /* LAC, dir */
CHECK_INDEX;
CHECK_ADDR_R (MA);
LAC = (LAC & 01000000) | M[MA];
break;
/* DAC: opcode 04 */
case 003: /* DAC, indir */
CHECK_AUTO_INC;
INDIRECT;
case 002: /* DAC, dir */
CHECK_INDEX;
CHECK_ADDR_W (MA);
M[MA] = LAC & 0777777;
break;
/* DZM: opcode 14 */
case 007: /* DZM, indir */
CHECK_AUTO_INC;
INDIRECT;
case 006: /* DZM, direct */
CHECK_INDEX;
CHECK_ADDR_W (MA);
M[MA] = 0;
break;
/* AND: opcode 50 */
case 025: /* AND, ind */
CHECK_AUTO_INC;
INDIRECT;
case 024: /* AND, dir */
CHECK_INDEX;
CHECK_ADDR_R (MA);
LAC = LAC & (M[MA] | 01000000);
break;
/* XOR: opcode 24 */
case 013: /* XOR, ind */
CHECK_AUTO_INC;
INDIRECT;
case 012: /* XOR, dir */
CHECK_INDEX;
CHECK_ADDR_R (MA);
LAC = LAC ^ M[MA];
break;
/* ADD: opcode 30 */
case 015: /* ADD, indir */
CHECK_AUTO_INC;
INDIRECT;
case 014: /* ADD, dir */
CHECK_INDEX;
CHECK_ADDR_R (MA);
t = (LAC & 0777777) + M[MA];
if (t > 0777777) t = (t + 1) & 0777777; /* end around carry */
if (((~LAC ^ M[MA]) & (LAC ^ t)) & 0400000) /* overflow? */
LAC = 01000000 | t; /* set link */
else LAC = (LAC & 01000000) | t;
break;
/* TAD: opcode 34 */
case 017: /* TAD, indir */
CHECK_AUTO_INC;
INDIRECT;
case 016: /* TAD, dir */
CHECK_INDEX;
CHECK_ADDR_R (MA);
LAC = (LAC + M[MA]) & 01777777;
break;
/* ISZ: opcode 44 */
case 023: /* ISZ, indir */
CHECK_AUTO_INC;
INDIRECT;
case 022: /* ISZ, dir */
CHECK_INDEX;
CHECK_ADDR_W (MA);
M[MA] = (M[MA] + 1) & 0777777;
if (M[MA] == 0) PC = INCR_ADDR (PC);
break;
/* SAD: opcode 54 */
case 027: /* SAD, indir */
CHECK_AUTO_INC;
INDIRECT;
case 026: /* SAD, dir */
CHECK_INDEX;
CHECK_ADDR_R (MA);
if ((LAC & 0777777) != M[MA]) PC = INCR_ADDR (PC);
break;
/* XCT: opcode 40 */
case 021: /* XCT, indir */
CHECK_AUTO_INC;
INDIRECT;
case 020: /* XCT, dir */
CHECK_INDEX;
CHECK_ADDR_R (MA);
if (usmd && (xct_count != 0)) { /* trap and chained? */
prvn = trap_pending = 1;
break; }
if (xct_count >= xct_max) { /* too many XCT's? */
reason = STOP_XCT;
break; }
xct_count = xct_count + 1; /* count XCT's */
#if defined (PDP9)
ion_defer = 1; /* defer intr */
#endif
goto xct_instr; /* go execute */
/* CAL: opcode 00
On the PDP-4 and PDP-7, CAL (I) is exactly the same as JMS (I) 20
On the PDP-9 and PDP-15, CAL clears user mode
On the PDP-9 and PDP-15 with API, CAL activates level 4
On the PDP-15, CAL goes to absolute 20, regardless of mode
*/
case 001: case 000: /* CAL */
t = usmd;
#if defined (PDP15)
MA = 020;
#else
MA = (memm? 0: PC & epcmask) | 020; /* MA = 20 */
#endif
#if defined (PDP9) || defined (PDP15)
usmd = 0; /* clear user mode */
if ((cpu_unit.flags & UNIT_NOAPI) == 0) { /* if API, act lvl 4 */
api_act = api_act | 010;
api_int = api_eval (&int_pend); }
#endif
if (IR & 0020000) { INDIRECT; } /* indirect? */
CHECK_ADDR_W (MA);
PCQ_ENTRY;
M[MA] = JMS_WORD (t); /* save state */
PC = INCR_ADDR (MA);
break;
/* JMS: opcode 010 */
case 005: /* JMS, indir */
CHECK_AUTO_INC;
INDIRECT;
case 004: /* JMS, dir */
CHECK_INDEX;
CHECK_ADDR_W (MA);
PCQ_ENTRY;
M[MA] = JMS_WORD (usmd); /* save state */
PC = INCR_ADDR (MA);
break;
/* JMP: opcode 60
Restore quirks:
On the PDP-7 and PDP-9, EMIR can only clear extend
On the PDP-15, any I triggers restore, but JMP I is conventional
*/
case 031: /* JMP, indir */
CHECK_AUTO_INC; /* check auto inc */
#if defined (PDP7) || defined (PDP9)
if (emir_pending && (((M[MA] >> 16) & 1) == 0)) memm = 0;
#endif
#if defined (PDP9)
if (rest_pending) { /* restore pending? */
LAC = ((M[MA] << 1) & 01000000) | (LAC & 0777777);
memm = (M[MA] >> 16) & 1;
usmd = (M[MA] >> 15) & 1; }
#endif
INDIRECT; /* complete indirect */
emir_pending = rest_pending = 0;
case 030: /* JMP, dir */
CHECK_INDEX;
PCQ_ENTRY; /* save old PC */
PC = MA;
break;
/* OPR: opcode 74 */
case 037: /* OPR, indir */
LAC = (LAC & 01000000) | IR; /* LAW */
break;
case 036: /* OPR, dir */
skp = 0; /* assume no skip */
switch ((IR >> 6) & 017) { /* decode IR<8:11> */
case 0: /* nop */
break;
case 1: /* SMA */
if ((LAC & 0400000) != 0) skp = 1;
break;
case 2: /* SZA */
if ((LAC & 0777777) == 0) skp = 1;
break;
case 3: /* SZA | SMA */
if (((LAC & 0777777) == 0) || ((LAC & 0400000) != 0))
skp = 1;
break;
case 4: /* SNL */
if (LAC >= 01000000) skp = 1;
break;
case 5: /* SNL | SMA */
if (LAC >= 0400000) skp = 1;
break;
case 6: /* SNL | SZA */
if ((LAC >= 01000000) || (LAC == 0)) skp = 1;
break;
case 7: /* SNL | SZA | SMA */
if ((LAC >= 0400000) || (LAC == 0)) skp = 1;
break;
case 010: /* SKP */
skp = 1;
break;
case 011: /* SPA */
if ((LAC & 0400000) == 0) skp = 1;
break;
case 012: /* SNA */
if ((LAC & 0777777) != 0) skp = 1;
break;
case 013: /* SNA & SPA */
if (((LAC & 0777777) != 0) && ((LAC & 0400000) == 0))
skp = 1;
break;
case 014: /* SZL */
if (LAC < 01000000) skp = 1;
break;
case 015: /* SZL & SPA */
if (LAC < 0400000) skp = 1;
break;
case 016: /* SZL & SNA */
if ((LAC < 01000000) && (LAC != 0)) skp = 1;
break;
case 017: /* SZL & SNA & SPA */
if ((LAC < 0400000) && (LAC != 0)) skp = 1;
break; } /* end switch skips */
/* OPR, continued */
switch (((IR >> 9) & 014) | (IR & 03)) { /* IR<5:6,16:17> */
case 0: /* NOP */
break;
case 1: /* CMA */
LAC = LAC ^ 0777777;
break;
case 2: /* CML */
LAC = LAC ^ 01000000;
break;
case 3: /* CML CMA */
LAC = LAC ^ 01777777;
break;
case 4: /* CLL */
LAC = LAC & 0777777;
break;
case 5: /* CLL CMA */
LAC = (LAC & 0777777) ^ 0777777;
break;
case 6: /* CLL CML = STL */
LAC = LAC | 01000000;
break;
case 7: /* CLL CML CMA */
LAC = (LAC | 01000000) ^ 0777777;
break;
case 010: /* CLA */
LAC = LAC & 01000000;
break;
case 011: /* CLA CMA = STA */
LAC = LAC | 0777777;
break;
case 012: /* CLA CML */
LAC = (LAC & 01000000) ^ 01000000;
break;
case 013: /* CLA CML CMA */
LAC = (LAC | 0777777) ^ 01000000;
break;
case 014: /* CLA CLL */
LAC = 0;
break;
case 015: /* CLA CLL CMA */
LAC = 0777777;
break;
case 016: /* CLA CLL CML */
LAC = 01000000;
break;
case 017: /* CLA CLL CML CMA */
LAC = 01777777;
break; } /* end decode */
/* OPR, continued */
if (IR & 0000004) { /* OAS */
#if defined (PDP9) || defined (PDP15)
if (usmd) prvn = trap_pending = 1;
else
#endif
LAC = LAC | SR; }
switch (((IR >> 8) & 04) | ((IR >> 3) & 03)) { /* decode IR<7,13:14> */
case 1: /* RAL */
LAC = ((LAC << 1) | (LAC >> 18)) & 01777777;
break;
case 2: /* RAR */
LAC = ((LAC >> 1) | (LAC << 18)) & 01777777;
break;
case 3: /* RAL RAR */
#if defined (PDP15) /* PDP-15 */
LAC = (LAC + 1) & 01777777; /* IAC */
#else /* PDP-4,-7,-9 */
reason = stop_inst; /* undefined */
#endif
break;
case 5: /* RTL */
LAC = ((LAC << 2) | (LAC >> 17)) & 01777777;
break;
case 6: /* RTR */
LAC = ((LAC >> 2) | (LAC << 17)) & 01777777;
break;
case 7: /* RTL RTR */
#if defined (PDP15) /* PDP-15 */
LAC = ((LAC >> 9) & 0777) | ((LAC & 0777) << 9) |
(LAC & 01000000); /* BSW */
#else /* PDP-4,-7,-9 */
reason = stop_inst; /* undefined */
#endif
break; } /* end switch rotate */
if (IR & 0000040) { /* HLT */
if (usmd) prvn = trap_pending = 1;
else reason = STOP_HALT; }
if (skp && !prvn) PC = INCR_ADDR (PC); /* if skip, inc PC */
break; /* end OPR */
/* EAE: opcode 64
The EAE is microprogrammed to execute variable length signed and
unsigned shift, multiply, divide, and normalize. Most commands are
controlled by a six bit step counter (SC). In the hardware, the step
counter is complemented on load and then counted up to zero; timing
guarantees an initial increment, which completes the two's complement
load. In the simulator, the SC is loaded normally and then counted
down to zero; the read SC command compensates.
*/
case 033: case 032: /* EAE */
if (cpu_unit.flags & UNIT_NOEAE) break; /* disabled? */
if (IR & 0020000) /* IR<4>? AC0 to L */
LAC = ((LAC << 1) & 01000000) | (LAC & 0777777);
if (IR & 0010000) MQ = 0; /* IR<5>? clear MQ */
if ((IR & 0004000) && (LAC & 0400000)) /* IR<6> and minus? */
eae_ac_sign = 01000000; /* set eae_ac_sign */
else eae_ac_sign = 0; /* if not, unsigned */
if (IR & 0002000) MQ = (MQ | LAC) & 0777777; /* IR<7>? or AC */
else if (eae_ac_sign) LAC = LAC ^ 0777777; /* if not, |AC| */
if (IR & 0001000) LAC = LAC & 01000000; /* IR<8>? clear AC */
link_init = LAC & 01000000; /* link temporary */
fill = link_init? 0777777: 0; /* fill = link */
esc = (IR & 077)? IR & 077: 0100; /* get eff SC */
switch ((IR >> 6) & 07) { /* case on IR<9:11> */
case 0: /* setup */
if (IR & 04) LAC = LAC ^ 0777777; /* IR<15>? ~AC */
if (IR & 02) LAC = LAC | MQ; /* IR<16>? or MQ */
if (IR & 01) LAC = LAC | ((-SC) & 077); /* IR<17>? or SC */
break;
case 1: /* multiply */
CHECK_ADDR_R (PC); /* validate PC */
MA = M[PC]; /* get next word */
PC = INCR_ADDR (PC); /* increment PC */
if (eae_ac_sign) MQ = MQ ^ 0777777; /* EAE AC sign? ~MQ */
LAC = LAC & 0777777; /* clear link */
for (SC = esc; SC != 0; SC--) { /* loop per step cnt */
if (MQ & 1) LAC = LAC + MA; /* MQ<17>? add */
MQ = (MQ >> 1) | ((LAC & 1) << 17);
LAC = LAC >> 1; } /* shift AC'MQ right */
if (eae_ac_sign ^ link_init) { /* result negative? */
LAC = LAC ^ 0777777;
MQ = MQ ^ 0777777; }
break;
/* EAE, continued
Divide uses a non-restoring divide. This code duplicates the PDP-7
algorithm, except for its use of two's complement arithmetic instead
of 1's complement.
The quotient is generated in one's complement form; therefore, the
quotient is complemented if the input operands had the same sign
(that is, if the quotient is positive).
*/
case 3: /* divide */
CHECK_ADDR_R (PC); /* validate PC */
MA = M[PC]; /* get next word */
PC = INCR_ADDR (PC); /* increment PC */
if (eae_ac_sign) MQ = MQ ^ 0777777; /* EAE AC sign? ~MQ */
if ((LAC & 0777777) >= MA) { /* overflow? */
LAC = (LAC - MA) | 01000000; /* set link */
break; }
LAC = LAC & 0777777; /* clear link */
t = 0; /* init loop */
for (SC = esc; SC != 0; SC--) { /* loop per step cnt */
if (t) LAC = (LAC + MA) & 01777777;
else LAC = (LAC - MA) & 01777777;
t = (LAC >> 18) & 1; /* quotient bit */
if (SC > 1) LAC = /* skip if last */
((LAC << 1) | (MQ >> 17)) & 01777777;
MQ = ((MQ << 1) | t) & 0777777; }
if (t) LAC = (LAC + MA) & 01777777;
if (eae_ac_sign) LAC = LAC ^ 0777777; /* sgn rem = sgn divd */
if (eae_ac_sign ^ link_init ^ 1) MQ = MQ ^ 0777777;
break;
/* EAE, continued
EAE shifts, whether left or right, fill from the link. If the
operand sign has been copied to the link, this provides correct
sign extension for one's complement numbers.
*/
case 4: /* normalize */
#if defined (PDP15)
if (!usmd) ion_defer = 2; /* free cycles */
#endif
for (SC = esc; (SC != 0) && ((LAC & 0400000) ==
((LAC << 1) & 0400000)); SC--) {
LAC = (LAC << 1) | ((MQ >> 17) & 1);
MQ = (MQ << 1) | (link_init >> 18); }
LAC = link_init | (LAC & 0777777); /* trim AC, restore L */
MQ = MQ & 0777777; /* trim MQ */
SC = SC & 077; /* trim SC */
break;
case 5: /* long right shift */
if (esc < 18) {
MQ = ((LAC << (18 - esc)) | (MQ >> esc)) & 0777777;
LAC = ((fill << (18 - esc)) | (LAC >> esc)) & 01777777; }
else {
if (esc < 36) MQ =
((fill << (36 - esc)) | (LAC >> (esc - 18))) & 0777777;
else MQ = fill;
LAC = link_init | fill; }
SC = 0; /* clear step count */
break;
case 6: /* long left shift */
if (esc < 18) {
LAC = link_init |
(((LAC << esc) | (MQ >> (18 - esc))) & 0777777);
MQ = ((MQ << esc) | (fill >> (18 - esc))) & 0777777; }
else {
if (esc < 36) LAC = link_init |
(((MQ << (esc - 18)) | (fill >> (36 - esc))) & 0777777);
else LAC = link_init | fill;
MQ = fill; }
SC = 0; /* clear step count */
break;
case 7: /* AC left shift */
if (esc < 18) LAC = link_init |
(((LAC << esc) | (fill >> (18 - esc))) & 0777777);
else LAC = link_init | fill;
SC = 0; /* clear step count */
break; } /* end switch IR */
break; /* end case EAE */
/* PDP-15 index operates: opcode 72 */
case 035: /* index operates */
#if defined (PDP15)
t = (IR & 0400)? IR | 0777000: IR & 0377; /* sext immediate */
switch ((IR >> 9) & 017) { /* case on IR<5:8> */
case 000: /* AAS */
LAC = (LAC & 01000000) | ((LAC + t) & 0777777);
if (SEXT (LAC & 0777777) >= SEXT (LR))
PC = INCR_ADDR (PC);
case 001: /* PAX */
XR = LAC & 0777777;
break;
case 002: /* PAL */
LR = LAC & 0777777;
break;
case 003: /* AAC */
LAC = (LAC & 01000000) | ((LAC + t) & 0777777);
break;
case 004: /* PXA */
LAC = (LAC & 01000000) | XR;
break;
case 005: /* AXS */
XR = (XR + t) & 0777777;
if (SEXT (XR) >= SEXT (LR)) PC = INCR_ADDR (PC);
break;
case 006: /* PXL */
LR = XR;
break;
case 010: /* PLA */
LAC = (LAC & 01000000) | LR;
break;
case 011: /* PLX */
XR = LR;
break;
case 014: /* CLAC */
LAC = LAC & 01000000;
break;
case 015: /* CLX */
XR = 0;
break;
case 016: /* CLLR */
LR = 0;
break;
case 017: /* AXR */
XR = (XR + t) & 0777777;
break; } /* end switch IR */
break; /* end case */
#endif
/* IOT: opcode 70
The 18b PDP's have different definitions of various control IOT's.
IOT PDP-4 PDP-7 PDP-9 PDP-15
700002 IOF IOF IOF IOF
700042 ION ION ION ION
700062 undefined ITON undefined undefined
701701 undefined undefined MPSK MPSK
701741 undefined undefined MPSNE MPSNE
701702 undefined undefined MPCV MPCV
701742 undefined undefined MPEU MPEU
701704 undefined undefined MPLD MPLD
701744 undefined undefined MPCNE MPCNE
703201 undefined undefined PFSF PFSF
703301 undefined TTS TTS TTS
703341 undefined SKP7 SKP7 SPCO
703302 undefined CAF CAF CAF
703304 undefined undefined DBK DBK
703344 undefined undefined DBR DBR
705501 undefined undefined SPI SPI
705502 undefined undefined RPL RPL
705504 undefined undefined ISA ISA
707701 undefined SEM SEM undefined
707741 undefined undefined undefined SKP15
707761 undefined undefined undefined SBA
707702 undefined EEM EEM undefined
707742 undefined EMIR EMIR RES
707762 undefined undefined undefined DBA
707704 undefined LEM LEM undefined
707764 undefined undefined undefined EBA
*/
case 034: /* IOT */
#if defined (PDP15)
if (IR & 0010000) { /* floating point? */
/* PC = fp15 (PC, IR); /* process */
break; }
#endif
if (usmd) { /* user mode? */
prvn = trap_pending = 1; /* trap */
break; }
device = (IR >> 6) & 077; /* device = IR<6:11> */
pulse = IR & 067; /* pulse = IR<12:17> */
if (IR & 0000010) LAC = LAC & 01000000; /* clear AC? */
iot_data = LAC & 0777777; /* AC unchanged */
/* PDP-4 system IOT's */
#if defined (PDP4)
switch (device) { /* decode IR<6:11> */
case 0: /* CPU and clock */
if (pulse == 002) ion = 0; /* IOF */
else if (pulse == 042) ion = ion_defer = 1; /* ION */
else iot_data = clk (pulse, iot_data);
break;
#endif
/* PDP-7 system IOT's */
#if defined (PDP7)
switch (device) { /* decode IR<6:11> */
case 0: /* CPU and clock */
if (pulse == 002) ion = 0; /* IOF */
else if (pulse == 042) ion = ion_defer = 1; /* ION */
else if (pulse == 062) /* ITON */
usmd = ion = ion_defer = 1;
else iot_data = clk (pulse, iot_data);
break;
case 033: /* CPU control */
if ((pulse == 001) || (pulse == 041)) PC = INCR_ADDR (PC);
else if (pulse == 002) reset_all (0); /* CAF */
break;
case 077: /* extended memory */
if ((pulse == 001) && memm) PC = INCR_ADDR (PC);
else if (pulse == 002) memm = 1; /* EEM */
else if (pulse == 042) /* EMIR */
memm = emir_pending = 1; /* ext on, restore */
else if (pulse == 004) memm = 0; /* LEM */
break;
#endif
/* PDP-9 and PDP-15 system IOT's */
#if defined (PDP9) || defined (PDP15)
ion_defer = 1; /* delay interrupts */
switch (device) { /* decode IR<6:11> */
case 000: /* CPU and clock */
if (pulse == 002) ion = 0; /* IOF */
else if (pulse == 042) ion = 1; /* ION */
else iot_data = clk (pulse, iot_data);
break;
case 017: /* mem protection */
if ((pulse == 001) && prvn) PC = INCR_ADDR (PC);
else if ((pulse == 041) && nexm) PC = INCR_ADDR (PC);
else if (pulse == 002) prvn = 0;
else if (pulse == 042) usmdbuf = 1;
else if (pulse == 004) BR = LAC & BRMASK;
else if (pulse == 044) nexm = 0;
break;
case 032: /* power fail */
if ((pulse == 001) && (TST_INT (PWRFL)))
PC = INCR_ADDR (PC);
break;
case 033: /* CPU control */
if ((pulse == 001) || (pulse == 041)) PC = INCR_ADDR (PC);
else if (pulse == 002) reset_all (0); /* CAF */
else if (pulse == 044) rest_pending = 1; /* DBR */
if (((cpu_unit.flags & UNIT_NOAPI) == 0) && (pulse & 004)) {
int32 t = api_ffo[api_act & 0377];
api_act = api_act & ~(0200 >> t); }
break;
case 055: /* API control */
if (cpu_unit.flags & UNIT_NOAPI) reason = stop_inst;
else if (pulse == 001) { /* SPI */
if (((LAC & SIGN) && api_enb) ||
((LAC & 0377) > api_act))
iot_data = iot_data | IOT_SKP; }
else if (pulse == 002) { /* RPL */
iot_data = iot_data | (api_enb << 17) |
(api_req << 8) | api_act; }
else if (pulse == 004) { /* ISA */
api_enb = (iot_data & SIGN)? 1: 0;
api_req = api_req | ((LAC >> 8) & 017);
api_act = api_act | (LAC & 0377); }
break;
#endif
#if defined (PDP9)
case 077: /* extended memory */
if ((pulse == 001) && memm) PC = INCR_ADDR (PC);
else if (pulse == 002) memm = 1; /* EEM */
else if (pulse == 042) /* EMIR */
memm = emir_pending = 1; /* ext on, restore */
else if (pulse == 004) memm = 0; /* LEM */
break;
#endif
#if defined (PDP15)
case 077: /* bank addressing */
if ((pulse == 041) || ((pulse == 061) && memm))
PC = INCR_ADDR (PC); /* SKP15, SBA */
else if (pulse == 042) rest_pending = 1; /* RES */
else if (pulse == 062) memm = 0; /* DBA */
else if (pulse == 064) memm = 1; /* EBA */
damask = memm? 017777: 07777; /* set dir addr mask */
epcmask = ADDRMASK & ~damask; /* extended PC mask */
break;
#endif
/* IOT, continued */
default: /* devices */
if (dev_tab[device]) /* defined? */
iot_data = dev_tab[device] (pulse, iot_data);
else reason = stop_inst; /* stop on flag */
break; } /* end switch device */
LAC = LAC | (iot_data & 0777777);
if (iot_data & IOT_SKP) PC = INCR_ADDR (PC);
if (iot_data >= IOT_REASON) reason = iot_data >> IOT_V_REASON;
api_int = api_eval (&int_pend); /* eval API */
break; /* end case IOT */
} /* end switch opcode */
if (api_cycle) { /* API cycle? */
api_cycle = 0; /* cycle over */
usmd = 0; /* exit user mode */
trap_pending = prvn = 0; } /* no priv viol */
} /* end while */
/* Simulation halted */
saved_PC = PC & ADDRMASK; /* save copies */
saved_LAC = LAC & 01777777;
saved_MQ = MQ & 0777777;
iors = upd_iors (); /* get IORS */
pcq_r->qptr = pcq_p; /* update pc q ptr */
return reason;
}
/* Evaluate API */
int32 api_eval (int32 *pend)
{
int32 i, hi;
for (i = *pend = 0; i < API_HLVL+1; i++) { /* any intr? */
if (int_hwre[i]) *pend = 1; }
if (api_enb == 0) return 0; /* off? no req */
api_req = api_req & ~0360; /* clr req<0:3> */
for (i = 0; i < API_HLVL; i++) { /* loop thru levels */
if (int_hwre[i]) /* req on level? */
api_req = api_req | (0200 >> i); } /* set api req */
hi = api_ffo[api_req & 0377]; /* find hi req */
if (hi < api_ffo[api_act & 0377]) return (hi + 1);
return 0;
}
/* Process IORS instruction */
int32 upd_iors (void)
{
int32 d, p;
d = (ion? IOS_ION: 0); /* ION */
for (p = 0; dev_iors[p] != NULL; p++) { /* loop thru table */
d = d | dev_iors[p](); } /* OR in results */
return d;
}
/* Reset routine */
t_stat cpu_reset (DEVICE *dptr)
{
SC = 0;
eae_ac_sign = 0;
ion = ion_defer = 0;
CLR_INT (PWRFL);
api_enb = api_req = api_act = 0;
BR = 0;
usmd = usmdbuf = 0;
memm = memm_init;
nexm = prvn = trap_pending = 0;
emir_pending = rest_pending = 0;
pcq_r = find_reg ("PCQ", NULL, dptr);
if (pcq_r) pcq_r->qptr = 0;
else return SCPE_IERR;
sim_brk_types = sim_brk_dflt = SWMASK ('E');
return SCPE_OK;
}
/* 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] & 0777777;
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 & 0777777;
return SCPE_OK;
}
/* Change memory size */
t_stat cpu_set_size (UNIT *uptr, int32 val, char *cptr, void *desc)
{
int32 mc = 0;
t_addr 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_devno (UNIT *uptr, int32 val, 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_devno (FILE *st, UNIT *uptr, int32 val, 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 pulse, 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, p;
static const uint8 std_dev[] =
#if defined (PDP4)
{ 000 };
#elif defined (PDP7)
{ 000, 033, 077 };
#else
{ 000, 017, 033, 055, 077 };
#endif
for (i = 0; i < DEV_MAX; i++) { /* clr tables */
dev_tab[i] = NULL;
dev_iors[i] = NULL; }
for (i = 0; i < ((uint32) sizeof (std_dev)); i++) /* std entries */
dev_tab[std_dev[i]] = &bad_dev;
for (i = p = 0; (dptr = sim_devices[i]) != NULL; i++) { /* add devices */
dibp = (DIB *) dptr->ctxt; /* get DIB */
if (dibp && !(dptr->flags & DEV_DIS)) { /* enabled? */
if (dibp->iors) dev_iors[p++] = dibp->iors; /* if IORS, add */
for (j = 0; j < dibp->num; j++) { /* loop thru disp */
if (dibp->dsp[j]) { /* any dispatch? */
if (dev_tab[dibp->dev + j]) { /* already filled? */
printf ("%s device number conflict at %02o\n",
dptr->name, dibp->dev + j);
if (sim_log) fprintf (sim_log,
"%s device number conflict at %02o\n",
dptr->name, dibp->dev + j);
return TRUE; }
dev_tab[dibp->dev + j] = dibp->dsp[j]; /* fill */
} /* end if dsp */
} /* end for j */
} /* end if enb */
} /* end for i */
return FALSE;
}