/* pdp18b_rp.c: RP15/RP02 disk pack 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.

   rp		RP15/RP02 disk pack

   06-Jan-02	RMS	Revised enable/disable support
   29-Nov-01	RMS	Added read only unit support
   25-Nov-01	RMS	Revised interrupt structure
			Changed FLG to array
   26-Apr-01	RMS	Added device enable/disable support
   14-Apr-99	RMS	Changed t_addr to unsigned
   29-Jun-96	RMS	Added unit enable/disable support
*/

#include "pdp18b_defs.h"

/* Constants */

#define RP_NUMWD	256				/* words/sector */
#define RP_NUMSC	10				/* sectors/surface */
#define RP_NUMSF	20				/* surfaces/cylinder */
#define RP_NUMCY	203				/* cylinders/drive */
#define RP_NUMDR	8				/* drives/controller */
#define RP_SIZE (RP_NUMCY * RP_NUMSF * RP_NUMSC * RP_NUMWD)  /* words/drive */

/* Unit specific flags */

#define UNIT_V_WLK	(UNIT_V_UF + 0)			/* hwre write lock */
#define UNIT_W_UF	2				/* user flags width */
#define UNIT_WLK	(1u << UNIT_V_WLK)
#define UNIT_WPRT	(UNIT_WLK | UNIT_RO)		/* write protect */

/* Parameters in the unit descriptor */

#define CYL		u3				/* current cylinder */
#define FUNC		u4				/* function */

/* Status register A */

#define STA_V_UNIT	15				/* unit select */
#define STA_M_UNIT	07
#define STA_V_FUNC	12				/* function */
#define STA_M_FUNC	07
#define  FN_IDLE	0
#define  FN_READ	1
#define  FN_WRITE	2
#define  FN_RECAL	3
#define  FN_SEEK	4
#define  FN_RDALL	5
#define  FN_WRALL	6
#define  FN_WRCHK	7
#define  FN_2ND		010				/* second state flag */
#define STA_IED		0004000				/* int enable done */
#define STA_IEA		0002000				/* int enable attn */
#define STA_GO		0001000				/* go */
#define STA_WPE		0000400				/* write lock error */
#define STA_NXC		0000200				/* nx cyl error */
#define STA_NXF		0000100				/* nx surface error */
#define STA_NXS		0000040				/* nx sector error */
#define STA_HNF		0000020				/* hdr not found */
#define STA_SUWP	0000010				/* sel unit wrt lock */
#define STA_SUSI	0000004				/* sel unit seek inc */
#define STA_DON		0000002				/* done */
#define STA_ERR		0000001				/* error */

#define STA_RW		0777000				/* read/write */
#define STA_EFLGS	(STA_WPE | STA_NXC | STA_NXF | STA_NXS | \
			 STA_HNF | STA_SUSI)		/* error flags */
#define STA_DYN		(STA_SUWP | STA_SUSI)		/* per unit status */
#define GET_UNIT(x)	(((x) >> STA_V_UNIT) & STA_M_UNIT)
#define GET_FUNC(x)	(((x) >> STA_V_FUNC) & STA_M_FUNC)

/* Status register B */

#define STB_V_ATT0	17				/* unit 0 attention */
#define STB_ATTN	0776000				/* attention flags */
#define STB_SUFU	0001000				/* sel unit unsafe */
#define STB_PGE		0000400				/* programming error */
#define STB_EOP		0000200				/* end of pack */
#define STB_TME		0000100				/* timing error */
#define STB_FME		0000040				/* format error */
#define STB_WCE		0000020				/* write check error */
#define STB_WPE		0000010				/* word parity error */
#define STB_LON		0000004				/* long parity error */
#define STB_SUSU	0000002				/* sel unit seeking */
#define STB_SUNR	0000001				/* sel unit not rdy */

#define STB_EFLGS	(STB_SUFU | STB_PGE | STB_EOP | STB_TME | STB_FME | \
			 STB_WCE | STB_WPE | STB_LON )	/* error flags */
#define STB_DYN		(STB_SUFU | STB_SUSU | STB_SUNR)	/* per unit */

/* Disk address */

#define DA_V_SECT	0				/* sector */
#define DA_M_SECT	017
#define DA_V_SURF	5
#define DA_M_SURF	037
#define DA_V_CYL	10				/* cylinder */
#define DA_M_CYL	0377
#define GET_SECT(x)	(((x) >> DA_V_SECT) & DA_M_SECT)
#define GET_SURF(x)	(((x) >> DA_V_SURF) & DA_M_SURF)
#define GET_CYL(x)	(((x) >> DA_V_CYL) & DA_M_CYL)
#define GET_DA(x)	((((GET_CYL (x) * RP_NUMSF) + GET_SURF (x)) * \
			RP_NUMSC) + GET_SECT (x))

#define RP_MIN 2
#define MAX(x,y) (((x) > (y))? (x): (y))

extern int32 M[];
extern int32 int_hwre[API_HLVL+1], dev_enb, nexm;
extern UNIT cpu_unit;
int32 rp_sta = 0;					/* status A */
int32 rp_stb = 0;					/* status B */
int32 rp_ma = 0;					/* memory address */
int32 rp_da = 0;					/* disk address */
int32 rp_wc = 0;					/* word count */
int32 rp_busy = 0;					/* busy */
int32 rp_stopioe = 1;					/* stop on error */
int32 rp_swait = 10;					/* seek time */
int32 rp_rwait = 10;					/* rotate time */
t_stat rp_svc (UNIT *uptr);
void rp_updsta (int32 newa, int32 newb);
t_stat rp_reset (DEVICE *dptr);
t_stat rp_attach (UNIT *uptr, char *cptr);
t_stat rp_detach (UNIT *uptr);

/* RP15 data structures

   rp_dev	RP device descriptor
   rp_unit	RP unit list
   rp_reg	RP register list
   rp_mod	RP modifier list
*/

UNIT rp_unit[] = {
	{ UDATA (&rp_svc, UNIT_FIX+UNIT_ATTABLE+UNIT_DISABLE, RP_SIZE) },
	{ UDATA (&rp_svc, UNIT_FIX+UNIT_ATTABLE+UNIT_DISABLE, RP_SIZE) },
	{ UDATA (&rp_svc, UNIT_FIX+UNIT_ATTABLE+UNIT_DISABLE, RP_SIZE) },
	{ UDATA (&rp_svc, UNIT_FIX+UNIT_ATTABLE+UNIT_DISABLE, RP_SIZE) },
	{ UDATA (&rp_svc, UNIT_FIX+UNIT_ATTABLE+UNIT_DISABLE, RP_SIZE) },
	{ UDATA (&rp_svc, UNIT_FIX+UNIT_ATTABLE+UNIT_DISABLE, RP_SIZE) },
	{ UDATA (&rp_svc, UNIT_FIX+UNIT_ATTABLE+UNIT_DISABLE, RP_SIZE) },
	{ UDATA (&rp_svc, UNIT_FIX+UNIT_ATTABLE+UNIT_DISABLE, RP_SIZE) } };

REG rp_reg[] = {
	{ ORDATA (STA, rp_sta, 18) },
	{ ORDATA (STB, rp_stb, 18) },
	{ ORDATA (DA, rp_da, 18) },
	{ ORDATA (MA, rp_ma, 18) },
	{ ORDATA (WC, rp_wc, 18) },
	{ FLDATA (INT, int_hwre[API_RP], INT_V_RP) },
	{ FLDATA (BUSY, rp_busy, 0) },
	{ FLDATA (STOP_IOE, rp_stopioe, 0) },
	{ DRDATA (STIME, rp_swait, 24), PV_LEFT },
	{ DRDATA (RTIME, rp_rwait, 24), PV_LEFT },
	{ URDATA (FLG, rp_unit[0].flags, 8, UNIT_W_UF, UNIT_V_UF - 1,
		  RP_NUMDR, REG_HRO) },
	{ FLDATA (*DEVENB, dev_enb, ENB_V_RP), REG_HRO },
	{ NULL }  };

MTAB rp_mod[] = {
	{ UNIT_WLK, 0, "write enabled", "WRITEENABLED", NULL },
	{ UNIT_WLK, UNIT_WLK, "write locked", "LOCKED", NULL },
	{ MTAB_XTD|MTAB_VDV, ENB_RP, NULL, "ENABLED", &set_enb },
	{ MTAB_XTD|MTAB_VDV, ENB_RP, NULL, "DISABLED", &set_dsb },
	{ 0 }  };

DEVICE rp_dev = {
	"RP", rp_unit, rp_reg, rp_mod,
	RP_NUMDR, 8, 24, 1, 8, 18,
	NULL, NULL, &rp_reset,
	NULL, &rp_attach, &rp_detach };

/* IOT routines */

int32 rp63 (int32 pulse, int32 AC)
{
rp_updsta (0, 0);
if (pulse == 001)					/* DPSF */
	return ((rp_sta & (STA_DON | STA_ERR)) || (rp_stb & STB_ATTN))?
		IOT_SKP + AC: AC;
if (pulse == 021)					/* DPSA */
	return (rp_stb & STB_ATTN)? IOT_SKP + AC: AC;
if (pulse == 041)					/* DPSJ */
	return (rp_sta & STA_DON)? IOT_SKP + AC: AC;
if (pulse == 061)					/* DPSE */
	return (rp_sta & STA_ERR)? IOT_SKP + AC: AC;
if (pulse == 002) return rp_sta;			/* DPOSA */
if (pulse == 022) return rp_stb;			/* DPOSB */
if (((pulse & 007) == 004) && rp_busy) {		/* busy? */
	rp_updsta (0, STB_PGE);
	return AC;  }
if (pulse == 004) {					/* DPLA */
	rp_da = AC;
	if (GET_SECT (rp_da) >= RP_NUMSC) rp_updsta (STA_NXS, 0);
	if (GET_SURF (rp_da) >= RP_NUMSF) rp_updsta (STA_NXF, 0);
	if (GET_CYL (rp_da) >= RP_NUMCY) rp_updsta (STA_NXC, 0);  }
if (pulse == 024) {					/* DPCS */
	rp_sta = rp_sta & ~(STA_HNF | STA_DON);
	rp_stb = rp_stb & ~(STB_FME | STB_WPE | STB_LON | STB_WCE |
		STB_TME | STB_PGE | STB_EOP);
	rp_updsta (0, 0);  }
if (pulse == 044) rp_ma = AC;				/* DPCA */
if (pulse == 064) rp_wc = AC;				/* DPWC */
return AC;
}

/* IOT 64 */

int32 rp64 (int32 pulse, int32 AC)
{
int32 u, f, c;
UNIT *uptr;

if (pulse == 021) return IOT_SKP + AC;			/* DPSN */
if (pulse == 002) return rp_unit[GET_UNIT (rp_sta)].CYL; /* DPOU */
if (pulse == 022) return rp_da;				/* DPOA */
if (pulse == 042) return rp_ma;				/* DPOC */
if (pulse == 062) return rp_wc;				/* DPOW */
if ((pulse & 007) != 004) return AC;
if (rp_busy) {						/* busy? */
	rp_updsta (0, STB_PGE);
	return AC;  }
if (pulse == 004) rp_sta = rp_sta & ~STA_RW;		/* DPCF */
if (pulse == 024) rp_sta = rp_sta & (AC | ~STA_RW);	/* DPLZ */
if (pulse == 044) rp_sta = rp_sta | (AC & STA_RW);	/* DPLO */
if (pulse == 064) rp_sta = (rp_sta & ~STA_RW) | (AC & STA_RW); /* DPLF */
if (rp_sta & STA_GO) {
	u = GET_UNIT (rp_sta);				/* get unit num */
	uptr = rp_dev.units + u;			/* select unit */
	if (sim_is_active (uptr)) return AC;		/* can't if busy */
	f = uptr -> FUNC = GET_FUNC (rp_sta);		/* get function */
	rp_busy = 1;					/* set ctrl busy */
	rp_sta = rp_sta & ~(STA_HNF | STA_DON);		/* clear flags */
	rp_stb = rp_stb & ~(STB_FME | STB_WPE | STB_LON | STB_WCE |
		STB_TME | STB_PGE | STB_EOP | (1 << (STB_V_ATT0 - u)));
	if (((uptr -> flags & UNIT_ATT) == 0) || (f == FN_IDLE) ||
	     (f == FN_SEEK) || (f == FN_RECAL))
		sim_activate (uptr, RP_MIN);		/* short delay */
	else {	c = GET_CYL (rp_da);
		c = abs (c - uptr -> CYL) * rp_swait;	/* seek time */
		sim_activate (uptr, MAX (RP_MIN, c + rp_rwait));  }  }
rp_updsta (0, 0);
return AC;
}

/* Unit service

   If function = idle, clear busy
   If seek or recal initial state, clear attention line, compute seek time,
	put on cylinder, set second state
   If unit not attached, give error
   If seek or recal second state, set attention line, compute errors
   Else complete data transfer command

   The unit control block contains the function and cylinder for
   the current command.
*/

static int32 fill[RP_NUMWD] = { 0 };
t_stat rp_svc (UNIT *uptr)
{
int32 f, u, comp, cyl, sect, surf;
int32 err, pa, da, wc, awc, i;

u = uptr - rp_dev.units;				/* get drv number */
f = uptr -> FUNC;					/* get function */
if (f == FN_IDLE) {					/* idle? */
	rp_busy = 0;					/* clear busy */
	return SCPE_OK;  }

if ((f == FN_SEEK) || (f == FN_RECAL)) {		/* seek or recal? */
	rp_busy = 0;					/* not busy */
	cyl = (f == FN_SEEK)? GET_CYL (rp_da): 0;	/* get cylinder */
	sim_activate (uptr, MAX (RP_MIN, abs (cyl - uptr -> CYL) * rp_swait));
	uptr -> CYL = cyl;				/* on cylinder */
	uptr -> FUNC = FN_SEEK | FN_2ND;		/* set second state */
	rp_updsta (0, 0);				/* update status */
	return SCPE_OK;  }

if (f == (FN_SEEK | FN_2ND)) {				/* seek done? */
	rp_updsta (0, rp_stb | (1 << (STB_V_ATT0 - u))); /* set attention */
	return SCPE_OK;  }

if ((uptr -> flags & UNIT_ATT) == 0) {			/* not attached? */
	rp_updsta (STA_DON, STB_SUFU);			/* done, unsafe */
	return IORETURN (rp_stopioe, SCPE_UNATT);  }

if ((f == FN_WRITE) && (uptr -> flags & UNIT_WPRT)) {	/* write locked? */
	rp_updsta (STA_DON | STA_WPE, 0);		/* error */
	return SCPE_OK;  }

if (GET_SECT (rp_da) >= RP_NUMSC) rp_updsta (STA_NXS, 0);
if (GET_SURF (rp_da) >= RP_NUMSF) rp_updsta (STA_NXF, 0);
if (GET_CYL (rp_da) >= RP_NUMCY) rp_updsta (STA_NXC, 0);
if (rp_sta & (STA_NXS | STA_NXF | STA_NXC)) {		/* or bad disk addr? */
	rp_updsta (STA_DON, STB_SUFU);			/* done, unsafe */
	return SCPE_OK;  }

pa = rp_ma & ADDRMASK;					/* get mem addr */
da = GET_DA (rp_da) * RP_NUMWD;				/* get disk addr */
wc = 01000000 - rp_wc;					/* get true wc */
if (((t_addr) (pa + wc)) > MEMSIZE) {			/* memory overrun? */
	nexm = 1;					/* set nexm flag */
	wc = MEMSIZE - pa;  }				/* limit xfer */
if ((da + wc) > RP_SIZE) {				/* disk overrun? */
	rp_updsta (0, STB_EOP);				/* error */
	wc = RP_SIZE - da;  }				/* limit xfer */

err = fseek (uptr -> fileref, da * sizeof (int), SEEK_SET);

if ((f == FN_READ) && (err == 0)) {			/* read? */
	awc = fxread (&M[pa], sizeof (int32), wc, uptr -> fileref);
	for ( ; awc < wc; awc++) M[pa + awc] = 0;
	err = ferror (uptr -> fileref);  }

if ((f == FN_WRITE) && (err == 0)) {			/* write? */
	fxwrite (&M[pa], sizeof (int32), wc, uptr -> fileref);
	err = ferror (uptr -> fileref);
	if ((err == 0) && (i = (wc & (RP_NUMWD - 1)))) {
		fxwrite (fill, sizeof (int), i, uptr -> fileref);
		err = ferror (uptr -> fileref);  }  }

if ((f == FN_WRCHK) && (err == 0)) {			/* write check? */
	for (i = 0; (err == 0) && (i < wc); i++)  {
		awc = fxread (&comp, sizeof (int32), 1, uptr -> fileref);
		if (awc == 0) comp = 0;
		if (comp != M[pa + i]) rp_updsta (0, STB_WCE);  }
	err = ferror (uptr -> fileref);  }

rp_wc = (rp_wc + wc) & 0777777;				/* final word count */
rp_ma = (rp_ma + wc) & 0777777;				/* final mem addr */
da = (da + wc + (RP_NUMWD - 1)) / RP_NUMWD;		/* final sector num */
cyl = da / (RP_NUMSC * RP_NUMSF);			/* get cyl */
if (cyl >= RP_NUMCY) cyl = RP_NUMCY - 1;
surf = (da % (RP_NUMSC * RP_NUMSF)) / RP_NUMSC;		/* get surface */
sect = (da % (RP_NUMSC * RP_NUMSF)) % RP_NUMSC;		/* get sector */
rp_da = (cyl << DA_V_CYL) | (surf << DA_V_SURF) | (sect << DA_V_SECT);
rp_busy = 0;						/* clear busy */
rp_updsta (STA_DON, 0);					/* set done */

if (err != 0) {						/* error? */
	perror ("RP I/O error");
	clearerr (uptr -> fileref);
	return IORETURN (rp_stopioe, SCPE_IOERR);  }
return SCPE_OK;
}

/* Update status */

void rp_updsta (int32 newa, int32 newb)
{
int32 f;
UNIT *uptr;

uptr = rp_dev.units + GET_UNIT (rp_sta);
rp_sta = (rp_sta & ~(STA_DYN | STA_ERR)) | newa;
rp_stb = (rp_stb & ~STB_DYN) | newb;
if (uptr -> flags & UNIT_WPRT) rp_sta = rp_sta | STA_SUWP;
if ((uptr -> flags & UNIT_ATT) == 0) rp_stb = rp_stb | STB_SUFU | STB_SUNR;
else if (sim_is_active (uptr)) {
	f = (uptr -> FUNC) & STA_M_FUNC;
	if ((f == FN_SEEK) || (f == FN_RECAL))
		rp_stb = rp_stb | STB_SUSU | STB_SUNR;  }
else if (uptr -> CYL >= RP_NUMCY) rp_sta = rp_sta | STA_SUSI;
if ((rp_sta & STA_EFLGS) || (rp_stb & STB_EFLGS)) rp_sta = rp_sta | STA_ERR;
if (((rp_sta & (STA_ERR | STA_DON)) && (rp_sta & STA_IED)) ||
    ((rp_stb & STB_ATTN) && (rp_sta & STA_IEA))) SET_INT (RP);
else CLR_INT (RP);
return;
}

/* Reset routine */

t_stat rp_reset (DEVICE *dptr)
{
int32 i;
UNIT *uptr;

rp_sta = rp_stb = rp_da = rp_wc = rp_ma = rp_busy = 0;
CLR_INT (RP);
for (i = 0; i < RP_NUMDR; i++) {
	uptr = rp_dev.units + i;
	sim_cancel (uptr);
	uptr -> CYL = uptr -> FUNC = 0;  }
return SCPE_OK;
}

/* IORS routine */

int32 rp_iors (void)
{
return ((rp_sta & (STA_ERR | STA_DON)) ||  (rp_stb & STB_ATTN))? IOS_RP: 0;
}

/* Attach unit */

t_stat rp_attach (UNIT *uptr, char *cptr)
{
t_stat reason;

reason = attach_unit (uptr, cptr);
rp_updsta (0, 0);
return reason;
}

/* Detach unit */

t_stat rp_detach (UNIT *uptr)
{
t_stat reason;

reason = detach_unit (uptr);
rp_updsta (0, 0);
return reason;
}
