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PDP11: RP11: Implement delayed CS_DONE for "initiation" commands (SEEK/HOME) #310

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PDP11: RP11: Implement delayed CS_DONE for "initiation" commands (SEEK/HOME) #310

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87 changes: 61 additions & 26 deletions PDP11/pdp11_rr.c
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Original file line number Diff line number Diff line change
Expand Up @@ -33,6 +33,14 @@
#include "pdp11_defs.h"
#include "sim_disk.h"

/* const_assert() */

#define _Cx(a, b) a ## b
#define _Ax(x) _Cx(_assert, x)
#define _Sx(n) (((n) << 1) - 1)
#define const_assert(c) do { static const char _Ax(__LINE__)[-_Sx(!(c))] \
= {!(c)}; (void) _Ax(__LINE__); } while (0)

/* Constants */

#define RPCONTR uint16
Expand Down Expand Up @@ -69,13 +77,13 @@
/* Parameters in the unit descriptor */
#define CYL u3 /* current cylinder */
#define HEAD u4 /* current track */
#define FUNC u5 /* current func */
#define STATUS u6 /* RPDS bits for the unit */
#define SEEKING us9 /* seek cmd underway */
#define FUNC us9 /* current func */
#define STATUS u5 /* RPDS bits for the unit */
#define SEEKING u6 /* seek cmd underway */

/* 4 dummy UNIBUS registers followed by... */
#define RP_IOFF 4
/* 12 real UNIBUS registers, so 16 registers total */
/* 12 real UNIBUS registers, so 16 registers total: 32 addresses */
#define RP_IOLN 040

/* RP02/RP03 particulars */
Expand All @@ -89,8 +97,7 @@ static struct drv_typ {
int32 seek_max; /* maximal seek, 0.1ms */
} drv_tab[] = {
{ RP_RP02, RP_NUMCY, RP_NUMBL, RP_SPARE, 200, 500, 800 },
{ RP_RP03, RP_NUMCY*2, RP_NUMBL*2, RP_SPARE*2, 75, 290, 550 },
{ NULL }
{ RP_RP03, RP_NUMCY*2, RP_NUMBL*2, RP_SPARE*2, 75, 290, 550 }
};

/* RPDS 776710, selected drive status, read-only except for the attention bits */
Expand Down Expand Up @@ -217,6 +224,7 @@ static BITFIELD rp_cs_bits[] = {
/* RPWC 776716, two's complement word count */
/* For PDP-11 must be even for data, and in multiples of 3 for format */
static BITFIELD rp_wc_bits[] = {
#define RPWC_IMP 0177777 /* implemented */
BITFFMT(WC,16,%u),
ENDBITS
};
Expand Down Expand Up @@ -346,7 +354,7 @@ static t_stat rr_wr (int32 data, int32 PA, int32 access);
static int32 rr_inta (void);
static t_stat rr_svc (UNIT *uptr);
static t_stat rr_reset (DEVICE *dptr);
static void rr_go (int32 func);
static void rr_go (int16 func);
static void rr_set_done (int32 error);
static void rr_clr_done (void);
static t_stat rr_boot (int32 unitno, DEVICE *dptr);
Expand Down Expand Up @@ -604,7 +612,8 @@ static t_stat rr_wr (int32 data, int32 PA, int32 access)
{
/* offset by base then decode <4:1> */
int32 rn = (((PA - rr_dib.ba) >> 1) & 017) - RP_IOFF;
int32 n, func, oval = rn < 0 ? 0 : *rr_regs[rn].valp;
int32 n, oval = rn < 0 ? 0 : *rr_regs[rn].valp;
int16 func;

if (access == WRITEB && 2 <= rn && rn <= 6)
data = RR_DATOB(oval, data);
Expand Down Expand Up @@ -648,13 +657,13 @@ static t_stat rr_wr (int32 data, int32 PA, int32 access)
&& (data & CSR_GO)) { /* ...and GO? */
rr_go(func); /* new function! */
} else if (!(rpcs & CSR_DONE) /* not ready? */
&& ((data & CSR_GO) || n)) { /* ...and: GO or desel? */
&& ((data & CSR_GO) | n)) { /* ...and: GO or desel? */
rper |= RPER_PGE; /* flag error */
}
break;

case 3: /* RPWC */
rpwc = data;
rpwc = data & RPWC_IMP;
break;

case 4: /* RPBA */
Expand Down Expand Up @@ -682,9 +691,20 @@ static t_stat rr_wr (int32 data, int32 PA, int32 access)
return SCPE_OK;
}

/* Complete seek initiation */

static t_stat rr_seek_init (UNIT *uptr)
{
rr_set_done(0); /* set done */
assert(uptr->SEEKING);
uptr->action = rr_svc;
sim_activate(uptr, uptr->SEEKING); /* seek ends then */
return SCPE_OK;
}

/* Initiate new function */

static void rr_go (int32 func)
static void rr_go (int16 func)
{
int32 i, type, cyl, head;
t_bool rd, wr;
Expand All @@ -704,6 +724,7 @@ static void rr_go (int32 func)
for (i = 0; i < RP_NUMDR; ++i) {
uptr = rr_dev.units + i;
sim_cancel(uptr);
uptr->action = rr_svc;
uptr->SEEKING = 0;
uptr->STATUS = 0;
uptr->FUNC = 0;
Expand All @@ -720,6 +741,7 @@ static void rr_go (int32 func)
rpcs &= ~(CSR_ERR | RPCS_HERR); /* clear summary */
i = GET_DRIVE(rpcs); /* get drive no */
uptr = rr_dev.units + i; /* selected unit */
assert(uptr->action == rr_svc);
assert(uptr->SEEKING || !uptr->FUNC); /* SEEK underway or idle */
uptr->STATUS &= ~(RPDS_DKER | RPDS_WLK); /* clear drive errors */

Expand Down Expand Up @@ -815,20 +837,30 @@ static void rr_go (int32 func)
else
i = drv_tab[type].seek_max;
if (func == RPCS_HOME || func == RPCS_SEEK) { /* seek? */
uptr->SEEKING = 1; /* drive is seeking */
rr_set_done(0); /* set done */
/* XXDP ZRPF-B test 0 fails because of the data race on INTFLG cleared
* _after_ initiating the SEEK. This code interrupts right away (as so
* could the device) causing INTFLG set by ISR to 1, to be lost. Hence,
* the test always sees INTFLG as 0, and cannot confirm the interrupt.
* INTFLG should have been cleared prior to SEEK. Fixed in ZRPB-E. */
uptr->action = rr_seek_init;
uptr->SEEKING = i; /* drive is seeking */
i = 10; /* enough for 16us */
/* XXDP ZRPF-B, Test 0 (cylinder positioning) fails because, even though
* it initializes INTFLG late (_after_ initiating the SEEK), the delayed
* CS_DONE here helps avoid the race (and an error) but only for the
* first iteration (cylinder 0). The next and all subsequent iterations
* begin with clearing attention bits in RDPS with a BIC instruction,
* like so: "BIC @#RPDS, @#RPDS", resulting in bare 0 actually sent by
* ALU to the UNIBUS in DATO cycle to RPDS, and causing no bits reset.
* That, in turn, causes the interrupt to occur immediately when RPCS is
* written with the new SEEK/AIE function (the attention bit still set)
* for the next cylinder, and that causes INTFLG to get set by the ISR
* just prior to when the test clears it. Thus, the test is unable to
* confirm the interrupt for all remaining cylinders. ZRPB-E fixes both
* bugs by initializing INTFLG before firing up SEEK/AIE, and also by
* using the more correct "MOVB @#RPDS, @#RPDS", instead of BIC. */
} else {
if (cyl != uptr->CYL || head != uptr->HEAD) {
assert(func != RPCS_RD_NOSEEK && func != RPCS_WR_NOSEEK);
uptr->STATUS |= RPDS_SEEK; /* drive is seeking */
}
i += RP_ROT_12; /* I/O takes longer */
/* XXDP ZRPB-E / ZRPF-B have two data race conditions in test 5 (data
/* XXDP ZRPB-E / ZRPF-B have two data race conditions in Test 5 (data
* reliability), which in ZRPB-E can be worked around with the following
* multiplier for all 15 steady patterns, but it does not help eliminate
* the second race in the last (random) pattern test, despite showing no
Expand Down Expand Up @@ -881,7 +913,8 @@ static void rr_seek_done (UNIT *uptr, t_bool cancel)

static t_stat rr_svc (UNIT *uptr)
{
int32 func = uptr->FUNC, cyl, head, sect, da, wc, n;
int32 cyl, head, sect, da, wc, n;
int16 func = uptr->FUNC;
t_seccnt todo, done;
t_stat ioerr;
uint32 ma;
Expand Down Expand Up @@ -1076,7 +1109,7 @@ static t_stat rr_svc (UNIT *uptr)
if (wc) { /* any xfer? */
assert(done);
rpwc += wc;
rpwc &= 0177777;
rpwc &= RPWC_IMP;
ma += wc << 1;
rpba = ma & RPBA_IMP;
rpcs &= ~RPCS_MEX;
Expand Down Expand Up @@ -1179,7 +1212,7 @@ static t_stat rr_reset (DEVICE *dptr)
int32 i;

/* compile-time sanity check first */
assert(sizeof(rr_regs)/sizeof(rr_regs[0]) == RP_IOLN/2 - RP_IOFF);
const_assert(sizeof(rr_regs)/sizeof(rr_regs[0]) == RP_IOLN/2 - RP_IOFF);

/* clear everything now */
rpds = 0;
Expand All @@ -1193,6 +1226,7 @@ static t_stat rr_reset (DEVICE *dptr)
for (i = 0; i < RP_NUMDR; ++i) {
UNIT* uptr = rr_dev.units + i;
sim_cancel(uptr);
uptr->action = rr_svc;
uptr->SEEKING = 0;
uptr->STATUS = 0;
uptr->FUNC = 0;
Expand Down Expand Up @@ -1226,7 +1260,7 @@ static t_stat rr_attach (UNIT *uptr, CONST char *cptr)

static t_stat rr_detach (UNIT *uptr)
{
int32 func = uptr->FUNC;
int16 func = uptr->FUNC;
rr_seek_done(uptr, 1/*cancel*/);
if (func) {
uptr->FUNC = 0; /* idle now */
Expand All @@ -1241,6 +1275,7 @@ static t_stat rr_detach (UNIT *uptr)
uptr->STATUS |= RPDS_UNSAFE; /* must reset before use */
assert(!sim_is_active(uptr));
assert(!uptr->SEEKING);
uptr->action = rr_svc;
uptr->HEAD = 0;
uptr->CYL = 0;
return sim_disk_detach(uptr);
Expand Down Expand Up @@ -1311,7 +1346,7 @@ static t_stat rr_set_wloa (UNIT *uptr, int32 val, CONST char *cptr, void *desc)
#define BOOT_LEN (sizeof (rr_boot_rom) / sizeof (rr_boot_rom[0]))

static const uint16 rr_boot_rom[] = {
/* EXPECTED M9312 REGISTER USE FOR BOOT PROMS: *
/* EXPECTED M9312 REGISTER USE FOR BOOT PROMS (IN THE BOOTED SOFTWARE): *
* R0 = UNIT NUMBER *
* R1 = CONTROLLER CSR *
* R2, R3 = TEMPORARIES *
Expand Down Expand Up @@ -1343,7 +1378,7 @@ static const uint16 rr_boot_rom[] = {
/* 002062 */ 0000747, /* BR BOOT ; START OVER */
/* 002064 */ 0105011, /* 2$: CLRB (R1) ; CLEAR CONTROLLER */
/* 002066 */ 0005007 /* CLR PC ; JUMP TO BOOTSTRAP */
/* .END */
/* 002070 .END */
};

static t_stat rr_boot (int32 unitno, DEVICE *dptr)
Expand Down Expand Up @@ -1381,7 +1416,7 @@ static t_stat rr_help (FILE *st, DEVICE *dptr, UNIT *uptr, int32 flag, const cha
"Disk drive parameters (all decimal):\n\n"
" Cylinders Heads Sects/Trk Capacity Average access\n"
" Total Spare Nominal Usable time, ms\n", st);
for (i = 0; i < sizeof(drv_tab)/sizeof(drv_tab[0]) - 1; ++i) {
for (i = 0; i < sizeof(drv_tab)/sizeof(drv_tab[0]); ++i) {
uint32 spare = GET_DA(drv_tab[i].spare, RP_NUMSF, RP_NUMSC);
uint32 total = drv_tab[i].size;
fprintf(st, "%.6s: %5u %5u %5u %5u"
Expand Down
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