| /* pdp10_tim.c: PDP-10 tim subsystem simulator | |
| Copyright (c) 1993-2012, Robert M Supnik | |
| Permission is hereby granted, free of charge, to any person obtaining a | |
| copy of this software and associated documentation files (the "Software"), | |
| 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. | |
| tim timer subsystem | |
| 18-Apr-12 RMS Removed absolute scheduling on reset | |
| 18-Jun-07 RMS Added UNIT_IDLE flag | |
| 03-Nov-06 RMS Rewritten to support idling | |
| 29-Oct-06 RMS Added clock coscheduling function | |
| 02-Feb-04 RMS Exported variables needed by Ethernet simulator | |
| 29-Jan-02 RMS New data structures | |
| 06-Jan-02 RMS Added enable/disable support | |
| 02-Dec-01 RMS Fixed bug in ITS PC sampling (found by Dave Conroy) | |
| 31-Aug-01 RMS Changed int64 to t_int64 for Windoze | |
| 17-Jul-01 RMS Moved function prototype | |
| 04-Jul-01 RMS Added DZ11 support | |
| */ | |
| #include "pdp10_defs.h" | |
| #include <math.h> | |
| #include <time.h> | |
| /* The KS timer works off a 4.100 MHz (243.9024 nsec) oscillator that | |
| * is independent of all other system timing. | |
| * | |
| * Two pieces of timekeeping hardware are exposed to the OS. | |
| * o The interval timer, which can interrupt at a programmed interval. | |
| * o The timebase, which records time (71 bits). | |
| * | |
| * The clock is architecturally readable in units of 243.9024 nsec via | |
| * the timebase. The implementation is somewhat different. | |
| * | |
| * The instructions that update the clocks specify time in these units. | |
| * | |
| * However, both timekeepers are incremented by the microcode when | |
| * a 12 bit counter overflows; e.g. at a period of 999.0244 usec. | |
| * Thus, the granularity of timer interrupts is approximately 1 msec. | |
| * | |
| * The OS programs the interval timer to interrupt as though the | |
| * the 12 least significant bits mattered. Thus, for a (roughly) | |
| * 1 msec interval, it would program 1 * 4096 into the interval timer. | |
| * The sign bit is not used, so 35-12 = 23 bits for the maximum interval, | |
| * which is 139.674 minutes. If any of the least significant bits | |
| * are non-zero, the interval is extended by 1 * 4096 counts. | |
| * | |
| * The timer merely sets the INTERVAL DONE flag in the APR flags. | |
| * Whether that actually causes an interrupt is controlled by the | |
| * APR interrupt enable for the flag and by the PI system. | |
| * | |
| * The flag is readable as an APR condition by RDAPR, and CONSO/Z APR,. | |
| * The flag is cleared by WRAPR 1b22!1b30 (clear, count done). | |
| * | |
| * The timebase is maintained with the 12 LSB zero in a workspace | |
| * register. When read by the OS, the actual value of the 10 MSB of | |
| * the hardware counter is inserted into those bits, providing increased | |
| * resolution. Although the system reference manual says otherwise, the | |
| * two LSB of the counter are read as zero by the microcode (DPM2), so | |
| * bits <70:71> of the timebase are also read as zero by software. | |
| * | |
| * When the OS sets the timebase, the 12 LSB that it supplies are ignored. | |
| * | |
| * The timebase is typically used for accurate time of day and CPU runtime | |
| * accounting. The simulator adjusts the equivalent of the 12-bit counter, | |
| * so CPU time will reflect simulator wall clock, not simulated machine cycles. | |
| * Since time of day must be accurate, this may result in the OS reporting | |
| * CPU times that are unrealistically faster - or slower - than on the | |
| * real hardware. | |
| * | |
| * This module also implements the TCU, a battery backed-up TOY clock | |
| * that was supported by TOPS-10, but not sold by DEC. | |
| */ | |
| /* Invariants */ | |
| #define TIM_HW_FREQ 4100000 /* 4.1Mhz */ | |
| #define TIM_HWRE_MASK 07777 /* Timer field of timebase */ | |
| #define TIM_BASE_RAZ 03 /* Timer bits read as zero by ucode */ | |
| #define UNIT_V_Y2K (UNIT_V_UF + 0) /* Y2K compliant OS */ | |
| #define UNIT_Y2K (1u << UNIT_V_Y2K) | |
| #define TIM_TMXR_FREQ 60 /* Target frequency (HZ) for tmxr polls */ | |
| /* Estimate of simulator instructions/sec for initialization and fixed timing. | |
| * This came from prior magic constant of 8000 at 60 tics/sec. | |
| * The machine was marketed as ~ 300KIPs, which would imply 3 usec/instr. | |
| * So 8,000 instructions should take ~24 msec. This would indicate that | |
| * the simulator from which this came was ~1.4 x the speed of the real | |
| * hardware. Current milage will vary. | |
| */ | |
| #define TIM_WAIT_IPS 480000 | |
| /* Clock mode TOPS-10/ITS */ | |
| #define TIM_TPS_T10 60 /* Initial frequency guess for TOPS-10 (close, not exact) */ | |
| #define TIM_ITS_QUANT (TIM_HW_FREQ / TIM_TPS_T10) /* ITS PC sampling and user runtime interval */ | |
| /* Clock mode TOPS-20/KLAD */ | |
| #define TIM_TPS_T20 1000 /* Initial estimate for TOPS-20 - 1msec seems fast? */ | |
| /* Probability function for TOPS-20 idlelock */ | |
| #define PROB(x) (((rand() * 100) / RAND_MAX) >= (x)) | |
| static d10 tim_base[2] = { 0, 0 }; /* 71b timebase */ | |
| static d10 tim_interval = 0; /* value programmed into the clock */ | |
| static d10 tim_period = 0; /* period in HW ticks adjusted for non-zero LSBs */ | |
| static d10 tim_new_period = 0; /* period for the next interval */ | |
| static int32 tim_mult; /* Multiple of interval timer period at which tmxr is polled */ | |
| d10 quant = 0; /* ITS quantum */ | |
| static int32 tim_t20_prob = 33; /* TOPS-20 prob */ | |
| /* Exported variables - initialized by set CPU model and reset */ | |
| int32 clk_tps; /* Interval clock ticks/sec */ | |
| int32 tmr_poll; /* SimH instructions/clock service */ | |
| int32 tmxr_poll; /* SimH instructions/term mux poll */ | |
| extern int32 apr_flg, pi_act; | |
| extern UNIT cpu_unit; | |
| extern d10 pcst; | |
| extern a10 pager_PC; | |
| extern int32 t20_idlelock; | |
| DEVICE tim_dev; | |
| static t_stat tcu_rd (int32 *data, int32 PA, int32 access); | |
| static t_stat tim_svc (UNIT *uptr); | |
| static t_stat tim_reset (DEVICE *dptr); | |
| static t_bool update_interval (d10 new_interval); | |
| static void tim_incr_base (d10 *base, d10 incr); | |
| extern d10 Read (a10 ea, int32 prv); | |
| extern d10 ReadM (a10 ea, int32 prv); | |
| extern void Write (a10 ea, d10 val, int32 prv); | |
| extern void WriteP (a10 ea, d10 val); | |
| extern int32 pi_eval (void); | |
| extern t_stat wr_nop (int32 data, int32 PA, int32 access); | |
| /* TIM data structures | |
| tim_dev TIM device descriptor | |
| tim_unit TIM unit descriptor | |
| tim_reg TIM register list | |
| */ | |
| DIB tcu_dib = { IOBA_TCU, IOLN_TCU, &tcu_rd, &wr_nop, 0 }; | |
| static UNIT tim_unit = { UDATA (&tim_svc, UNIT_IDLE, 0), 0 }; | |
| static REG tim_reg[] = { | |
| { BRDATAD (TIMEBASE, tim_base, 8, 36, 2, "time base (double precision)") }, | |
| { ORDATAD (PERIOD, tim_period, 36, "reset value for interval") }, | |
| { ORDATAD (QUANT, quant, 36, "quantum timer (ITS only)") }, | |
| { DRDATAD (TIME, tim_unit.wait, 24, "tick delay"), REG_NZ + PV_LEFT }, | |
| { DRDATA (PROB, tim_t20_prob, 6), REG_NZ + PV_LEFT + REG_HIDDEN }, | |
| { DRDATA (POLL, tmr_poll, 32), REG_HRO + PV_LEFT }, | |
| { DRDATA (MUXPOLL, tmxr_poll, 32), REG_HRO + PV_LEFT }, | |
| { DRDATA (MULT, tim_mult, 6), REG_HRO + PV_LEFT }, | |
| { DRDATA (TPS, clk_tps, 12), REG_HRO + PV_LEFT }, | |
| { NULL } | |
| }; | |
| static MTAB tim_mod[] = { | |
| { UNIT_Y2K, 0, "non Y2K OS", "NOY2K", NULL }, | |
| { UNIT_Y2K, UNIT_Y2K, "Y2K OS", "Y2K", NULL }, | |
| { MTAB_XTD|MTAB_VDV, 000, "ADDRESS", NULL, | |
| NULL, &show_addr, NULL }, | |
| { 0 } | |
| }; | |
| DEVICE tim_dev = { | |
| "TIM", &tim_unit, tim_reg, tim_mod, | |
| 1, 0, 0, 0, 0, 0, | |
| NULL, NULL, &tim_reset, | |
| NULL, NULL, NULL, | |
| &tcu_dib, DEV_UBUS | |
| }; | |
| /* Timer instructions */ | |
| /* Timebase - the timer is always running at less than hardware frequency, | |
| * need to interpolate the value by calculating how much of the current | |
| * clock tick has elapsed, and what that equates to in sysfreq units. | |
| */ | |
| t_bool rdtim (a10 ea, int32 prv) | |
| { | |
| double fract; /* Fraction of current interval completed */ | |
| d10 tempbase[2]; /* Local copy of tempbase to interpolate */ | |
| int32 used; /* Used part of curr intv, in hw ticks */ | |
| d10 incr; /* Interpolated increment for timebase */ | |
| tempbase[0] = tim_base[0]; /* copy time base */ | |
| tempbase[1] = tim_base[1]; | |
| used = tmr_poll - (sim_activate_time (&tim_unit) - 1); | |
| fract = ((double)used) / ((double)tmr_poll); | |
| /* | |
| * incr is approximate number of HW ticks to add to the timebase | |
| * value returned. This does NOT update the timebase. | |
| */ | |
| incr = (d10)(fract * (double)tim_period); | |
| tim_incr_base (tempbase, incr); | |
| /* Although the two LSB of the counter contribute carry to the | |
| * value, they are read as zero by microcode, and thus cleared here. | |
| * | |
| * The reason that these bits are forced to zero in the hardware is | |
| * that the counter is in a different clock domain from the microcode. | |
| * To make the domain crossing, the microcode reads the counter | |
| * until two consecutive values match. | |
| * | |
| * Since the microcode cycle time is 300 nsec, the LSBs of the | |
| * counter run too fast (244 nsec) for the strategy to work. | |
| * Ignoring the two LSB ensures that the value can't change any | |
| * faster than ~976 nsec, which guarantees a stable value can be | |
| * obtained in at most three attempts. | |
| */ | |
| tempbase[1] &= ~((d10) TIM_BASE_RAZ); | |
| /* If the destination is arranged so that the first word is OK, but | |
| * the second pagefaults, the value will be half-written. As we | |
| * expect the PFH to restart the instruction, the both halves will | |
| * be written the second time. We could read and write back both | |
| * halves to avoid this, but the hardware doesn't seem to either. | |
| */ | |
| Write (ea, tempbase[0], prv); | |
| Write (INCA(ea), tempbase[1], prv); | |
| return FALSE; | |
| } | |
| t_bool wrtim (a10 ea, int32 prv) | |
| { | |
| tim_base[0] = Read (ea, prv); | |
| tim_base[1] = CLRS (Read (INCA (ea), prv) & ~((d10) TIM_HWRE_MASK)); | |
| return FALSE; | |
| } | |
| t_bool rdint (a10 ea, int32 prv) | |
| { | |
| Write (ea, tim_interval, prv); | |
| return FALSE; | |
| } | |
| /* write a new interval timer period (in timer ticks). | |
| * This does not clear the harware counter, so the first | |
| * completion can come up to ~1 msc later than the new | |
| * period. | |
| */ | |
| t_bool wrint (a10 ea, int32 prv) | |
| { | |
| tim_interval = CLRS (Read (ea, prv)); | |
| return update_interval (tim_interval); | |
| } | |
| static t_bool update_interval (d10 new_interval) | |
| { | |
| /* | |
| * The value provided is in hardware clicks. For a frequency of 4.1 | |
| * MHz, that means that dividing by 4096 (shifting 12 to the right) we get | |
| * the aproximate value in millisenconds. If any of rhe rightmost bits is | |
| * one, we add one unit (4096 ticks ). Reference: | |
| * AA-H391A-TK_DECsystem-10_DECSYSTEM-20_Processor_Reference_Jun1982.pdf | |
| * (page 4-37) | |
| */ | |
| tim_new_period = new_interval & ~TIM_HWRE_MASK; | |
| if (new_interval & TIM_HWRE_MASK) tim_new_period += 010000; | |
| /* clk_tps is the new number of clocks ticks per second */ | |
| clk_tps = (int32) ceil((double)TIM_HW_FREQ /(double)tim_new_period); | |
| /* tmxr is polled every tim_mult clks. Compute the divisor matching the target. */ | |
| tim_mult = (clk_tps <= TIM_TMXR_FREQ) ? 1 : (clk_tps / TIM_TMXR_FREQ) ; | |
| /* Estimate instructions/tick for fixed timing - just for KLAD */ | |
| tim_unit.wait = TIM_WAIT_IPS / clk_tps; | |
| tmxr_poll = tim_unit.wait * tim_mult; | |
| /* The next tim_svc will update the activation time. | |
| * | |
| */ | |
| return FALSE; | |
| } | |
| /* Timer service - the timer is only serviced when the interval | |
| * programmed in tim_period by wrint expires. If the interval | |
| * changes, the timebase update is based on the previous interval. | |
| * The interval calibration is based on what the new interval will be. | |
| */ | |
| static t_stat tim_svc (UNIT *uptr) | |
| { | |
| if (cpu_unit.flags & UNIT_KLAD) /* diags? */ | |
| tmr_poll = uptr->wait; /* fixed clock */ | |
| else tmr_poll = sim_rtc_calb (clk_tps); /* else calibrate */ | |
| sim_activate (uptr, tmr_poll); /* reactivate unit */ | |
| tmxr_poll = tmr_poll * tim_mult; /* set mux poll */ | |
| tim_incr_base (tim_base, tim_period); /* incr time base based on period of expired interval */ | |
| tim_period = tim_new_period; /* If interval has changed, update period */ | |
| apr_flg = apr_flg | APRF_TIM; /* request interrupt */ | |
| if (Q_ITS) { /* ITS? */ | |
| if (pi_act == 0) | |
| quant = (quant + TIM_ITS_QUANT) & DMASK; | |
| if (TSTS (pcst)) { /* PC sampling? */ | |
| WriteP ((a10) pcst & AMASK, pager_PC); /* store sample */ | |
| pcst = AOB (pcst); /* add 1,,1 */ | |
| } | |
| } /* end ITS */ | |
| else if (t20_idlelock && PROB (100 - tim_t20_prob)) | |
| t20_idlelock = 0; | |
| return SCPE_OK; | |
| } | |
| static void tim_incr_base (d10 *base, d10 incr) | |
| { | |
| base[1] = base[1] + incr; /* add on incr */ | |
| base[0] = base[0] + (base[1] >> 35); /* carry to high */ | |
| base[0] = base[0] & DMASK; /* mask high */ | |
| base[1] = base[1] & MMASK; /* mask low */ | |
| return; | |
| } | |
| /* Timer reset */ | |
| static t_stat tim_reset (DEVICE *dptr) | |
| { | |
| sim_register_clock_unit (&tim_unit); /* declare clock unit */ | |
| tim_base[0] = tim_base[1] = 0; /* clear timebase (HW does) */ | |
| /* HW does not initialize the interval timer, so the rate at which the timer flag | |
| * sets is random. No sensible user would enable interrupts or check the flag without | |
| * setting an interval. The timebase is intialized to zero by microcode intialization. | |
| * It increments based on the overflow, so it would be reasonable for a user to just | |
| * read it twice and subtract the values to determine elapsed time. | |
| * | |
| * Simply to keep the simulator overhead down until the interval timer is initialized | |
| * by the OS or diagnostic, we will set the internal interval to ~17 msec here. | |
| * This allows the service routine to increment the timebase, and gives RDTIME an | |
| * baseline for its interpolation. | |
| */ | |
| tim_interval = 0; | |
| clk_tps = 60; | |
| update_interval(17*4096); | |
| apr_flg = apr_flg & ~APRF_TIM; /* clear interrupt */ | |
| tmr_poll = sim_rtc_init (tim_unit.wait); /* init timer */ | |
| sim_activate (&tim_unit, tmr_poll); /* activate unit */ | |
| tmxr_poll = tmr_poll * tim_mult; /* set mux poll */ | |
| return SCPE_OK; | |
| } | |
| /* Set timer parameters from CPU model */ | |
| t_stat tim_set_mod (UNIT *uptr, int32 val, char *cptr, void *desc) | |
| { | |
| if (val & (UNIT_T20|UNIT_KLAD)) { | |
| clk_tps = TIM_TPS_T20; | |
| update_interval(((d10)(1000*4096))/clk_tps); | |
| tmr_poll = tim_unit.wait; | |
| uptr->flags = uptr->flags | UNIT_Y2K; | |
| } | |
| else { | |
| clk_tps = TIM_TPS_T10; | |
| update_interval (((d10)(1000*4096))/clk_tps); | |
| tmr_poll = tim_unit.wait; | |
| if (Q_ITS) | |
| uptr->flags = uptr->flags | UNIT_Y2K; | |
| else uptr->flags = uptr->flags & ~UNIT_Y2K; | |
| } | |
| return SCPE_OK; | |
| } | |
| /* Time of year clock | |
| * | |
| * The hardware clock was never sold by DEC, but support for it exists | |
| * in TOPS-10. Code was also available for RSX20F to read and report the | |
| * to the OS via its20F's SETSPD task. This implements only the read functions. | |
| * | |
| * The manufacturer's manual can be found at | |
| * http://bitsavers.trailing-edge.com/pdf/digitalPathways/tcu-150.pdf | |
| */ | |
| static t_stat tcu_rd (int32 *data, int32 PA, int32 access) | |
| { | |
| time_t curtim; | |
| struct tm *tptr; | |
| curtim = time (NULL); /* get time */ | |
| tptr = localtime (&curtim); /* decompose */ | |
| if (tptr == NULL) | |
| return SCPE_NXM; | |
| if ((tptr->tm_year > 99) && !(tim_unit.flags & UNIT_Y2K)) | |
| tptr->tm_year = 99; /* Y2K prob? */ | |
| switch ((PA >> 1) & 03) { /* decode PA<3:1> */ | |
| case 0: /* year/month/day */ | |
| *data = (((tptr->tm_year) & 0177) << 9) | | |
| (((tptr->tm_mon + 1) & 017) << 5) | | |
| ((tptr->tm_mday) & 037); | |
| return SCPE_OK; | |
| case 1: /* hour/minute */ | |
| *data = (((tptr->tm_hour) & 037) << 8) | | |
| ((tptr->tm_min) & 077); | |
| return SCPE_OK; | |
| case 2: /* second */ | |
| *data = (tptr->tm_sec) & 077; | |
| return SCPE_OK; | |
| case 3: /* status */ | |
| *data = CSR_DONE; | |
| return SCPE_OK; | |
| } | |
| return SCPE_NXM; /* can't get here */ | |
| } |