Sigh... just looked through ka630_* modules.
Anyway, the byte access/word addressing is in the spec. So the code is
allowing writes to bytes that don't exist. Further, it is trying to deal
with lengths other than byte or word, and the access and control paths
don't exist in the hardware.
VMS uses strictly byte reads and writes to access the watch registers. I
don't know what the console ROM might be doing; sources are not available.
/Bob
/* NVR: non-volatile RAM - stored in a buffered file */
int32 nvr_rd (int32 pa)
{
int32 rg = (pa - NVRBASE) & ~01; /* force even; ignore odd bytes */
int32 result;
if (rg < 14) /* watch chip */
result = wtc_rd (pa);
else
result = nvr[rg];
sim_debug (DBG_REG, &nvr_dev, "nvr_rd(pa=0x%X) returns: 0x%X\n", pa,
result);
return result;
}
void nvr_wr (int32 pa, int32 val, int32 lnt)
{
int32 rg = (pa - NVRBASE) & ~01;
if (rg < 14) /* watch chip */
wtc_wr (pa, val, lnt);
else
nvr[rg] = (uint8) val;
// sim_debug (DBG_REG, &nvr_dev, "nvr_wr(pa=0x%X,val=0x%04X,lnt=%d)
nvr[%02X] was %04X now %04X\n", pa, val, lnt, rg, orig_nvr, nvr[rg] |
(nvr[rg+1] << 8));
}
}
/* NVR examine */
t_stat nvr_ex (t_value *vptr, t_addr exta, UNIT *uptr, int32 sw)
{
uint32 addr = (uint32) exta;
if ((vptr == NULL) || (addr & 01))
return SCPE_ARG;
if (addr >= NVRBASE+NVRASIZE)
return SCPE_NXM;
*vptr = nvr[addr];
return SCPE_OK;
}
/* NVR deposit */
t_stat nvr_dep (t_value val, t_addr exta, UNIT *uptr, int32 sw)
{
uint32 addr = (uint32) exta;
if (addr & 01)
return SCPE_ARG;
if (addr >= NVRBASE+NVRASIZE)
return SCPE_NXM;
nvr[addr] = (uint8) val;
return SCPE_OK;
}
Note also that the specification of NVR as "4, 16, 32" should be "2, 16,
16". It's a byte-wide memory, but because odd addresses don't work, it
has to be specified this way for save/restore.
/Bob
On 4/11/2016 12:00 PM, [email protected] wrote:
------------------------------
Message: 2
Date: Mon, 11 Apr 2016 08:51:08 -0700
From: Mark Pizzolato<[email protected]>
To:"[email protected]" <[email protected]>
Subject: Re: [Simh] MicroVAX II time
Message-ID:
<03006e3fc39b5a48ab9dbccc101090a82dd620f...@redroof2.alohasunset.com>
Content-Type: text/plain; charset="utf-8"
Actually, the watch chip is implemented it is implemented as a separate module
and DEVICE in VAX/vax_watch.c.
The nvr initializes the valid bit in the watch check when the NVR is attached
and
clears it when NVR is detached.
Well, I didn’t check the details about 16bit or byte access, but the watch chip
works correctly for me if I use Wilm's config and point it at my generic test
disk.
I get prompted for time IF I don't attach the NVR and don't if I do.
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