195 lines
4.6 KiB
C
195 lines
4.6 KiB
C
/*
|
|
* Copyright (c) 2023 Anders Magnusson.
|
|
* All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
|
|
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
|
|
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
|
|
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
|
|
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
|
|
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
|
|
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
|
|
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
|
|
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
|
|
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
|
*/
|
|
|
|
|
|
#include "sim_defs.h"
|
|
|
|
#include "nd100_defs.h"
|
|
|
|
#define MAXMEMSIZE 512*1024
|
|
|
|
t_stat mm_reset(DEVICE *dptr);
|
|
|
|
uint16 PM[MAXMEMSIZE];
|
|
uint16 PCR[16]; /* Paging control register */
|
|
uint16 ptmap[4][64]; /* protection */
|
|
uint16 pmmap[4][64]; /* memory mapping */
|
|
|
|
#define ISDIS() (mm_dev.flags & DEV_DIS)
|
|
|
|
UNIT mm_unit = { UDATA(NULL, UNIT_FIX+UNIT_DISABLE+UNIT_BINK, 0) };
|
|
|
|
REG mm_reg[] = {
|
|
{ BRDATA(PCR, PCR, 8, 16, 16) },
|
|
{ NULL }
|
|
};
|
|
|
|
|
|
DEVICE mm_dev = {
|
|
"MM", &mm_unit, mm_reg, 0,
|
|
1, 8, 16, 1, 8, 16,
|
|
0, 0, &mm_reset,
|
|
NULL, NULL, NULL,
|
|
NULL, DEV_DISABLE+DEV_DIS
|
|
};
|
|
|
|
/*
|
|
* Read a byte. 0 in lr is left byte, 1 is right byte.
|
|
*/
|
|
uint8
|
|
rdbyte(int vaddr, int lr/* , int how*/)
|
|
{
|
|
uint16 val = rdmem(vaddr);
|
|
|
|
return lr ? val & 0377 : val >> 8;
|
|
}
|
|
|
|
/*
|
|
* Write a byte. 0 in lr is left byte, 1 is right byte.
|
|
*/
|
|
void
|
|
wrbyte(int vaddr, int val, int lr/* , int how*/)
|
|
{
|
|
uint16 ov = rdmem(vaddr);
|
|
|
|
val &= 0377; /* sanity */
|
|
ov = lr ? (ov & 0177400) | val : (ov & 0377) | (val << 8);
|
|
wrmem(vaddr, ov);
|
|
}
|
|
|
|
/*
|
|
* Access shadow memory. if:
|
|
* sexi == 0 && v >= 0177400 && (myring == 3 || pon == 0)
|
|
* or
|
|
* sexi == 1 && v >= 0177000 && (myring == 3 || pon == 0)
|
|
*/
|
|
static int
|
|
is_shadow(int vaddr)
|
|
{
|
|
if ((PCR[curlvl] & 03) < 3 && ISPON())
|
|
return 0; /* not valid */
|
|
if (ISSEX())
|
|
return 1;
|
|
return (vaddr >= 0177400);
|
|
}
|
|
|
|
/*
|
|
* Fetch a word from the shadow mem.
|
|
*/
|
|
static int
|
|
shadowrd(int v)
|
|
{
|
|
int pt;
|
|
int x = 0;
|
|
|
|
if (ISSEX())
|
|
x = v & 1, v >>= 1;
|
|
pt = (v >> 6) & 03;
|
|
v &= 077;
|
|
|
|
if (ISSEX())
|
|
return x ? pmmap[pt][v] : ptmap[pt][v];
|
|
return ptmap[pt][v]|pmmap[pt][v];
|
|
}
|
|
|
|
/*
|
|
* Write a word to the shadow mem.
|
|
*/
|
|
static void
|
|
shadowwr(int v, int dat)
|
|
{
|
|
int pt;
|
|
int x = 0;
|
|
|
|
if (ISSEX())
|
|
x = v & 1, v >>= 1;
|
|
pt = (v >> 6) & 03;
|
|
v &= 077;
|
|
|
|
if (ISSEX()) {
|
|
if (x)
|
|
pmmap[pt][v] = dat;
|
|
else
|
|
ptmap[pt][v] = dat;
|
|
} else {
|
|
pmmap[pt][v] = dat & 0777;
|
|
ptmap[pt][v] = dat & 0177000;
|
|
}
|
|
}
|
|
|
|
|
|
uint16
|
|
rdmem(int vaddr/* , int how*/)
|
|
{
|
|
int pt;
|
|
|
|
vaddr &= 0177777;
|
|
|
|
if ((vaddr >= 0177000) && is_shadow(vaddr))
|
|
return shadowrd(vaddr);
|
|
/* Mark page as read */
|
|
if (ISPON()) {
|
|
pt = (PCR[curlvl] >> 8) & 03;
|
|
ptmap[pt][vaddr >> 10] |= PT_PGU;
|
|
}
|
|
|
|
// if (ISPON() == 0)
|
|
return PM[vaddr];
|
|
|
|
}
|
|
|
|
void
|
|
wrmem(int vaddr, int val/* , int how*/)
|
|
{
|
|
vaddr &= 0177777;
|
|
if ((vaddr >= 0177000) && is_shadow(vaddr)) {
|
|
shadowwr(vaddr, val);
|
|
return;
|
|
}
|
|
PM[vaddr] = val;
|
|
}
|
|
|
|
void
|
|
mm_wrpcr(void)
|
|
{
|
|
if (ISDIS())
|
|
return;
|
|
PCR[(regA >> 3) & 017] = regA & 03603;
|
|
}
|
|
|
|
void
|
|
mm_rdpcr(void)
|
|
{
|
|
if (ISDIS())
|
|
return;
|
|
regA = PCR[(regA >> 3) & 017];
|
|
}
|
|
|
|
|
|
t_stat
|
|
mm_reset(DEVICE *dptr)
|
|
{
|
|
return 0;
|
|
}
|