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The Massbus byte count register was incorrectly presumed to be constant during a complete I/O transfer request (it can change due to DMA activity). Prior to the conversion to use the sim_disk library, the Massbus byte count was only read once. After the code restructuring it was read early in the processing and again later in transfer processing. The subsequent read returned a different value which ultimately caused the problems. This fixes issue #30.

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This commit is contained in:
Mark Pizzolato 2013-01-29 04:43:43 -08:00
parent 97de4dbae6
commit 659873bebb
1 changed files with 5 additions and 4 deletions
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9
PDP11/pdp11_rp.c
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@ -563,6 +563,7 @@ uint16 rper2[RP_NUMDR] = { 0 }; /* error status 2 */
uint16 rper3[RP_NUMDR] = { 0 }; /* error status 3 */
uint16 rpec1[RP_NUMDR] = { 0 }; /* ECC correction 1 */
uint16 rpec2[RP_NUMDR] = { 0 }; /* ECC correction 2 */
uint16 rpxbc[RP_NUMDR] = { 0 }; /* Byte Count Copy */
int32 rp_stopioe = 1; /* stop on error */
int32 rp_swait = 26; /* seek time */
int32 rp_rwait = 10; /* rotate time */
@ -1135,7 +1136,6 @@ if ((uptr->flags & UNIT_ATT) == 0) { /* not attached? */
rp_update_ds (DS_ATA, drv); /* set attn */
return (rp_stopioe? SCPE_UNATT: SCPE_OK);
}
if (!uptr->io_complete) { /* Top End (I/O Initiation) Processing */
switch (fnc) { /* case on function */
@ -1164,7 +1164,7 @@ if (!uptr->io_complete) { /* Top End (I/O Initiation) Processing */
case FNC_WCHK: /* write check */
case FNC_READ: /* read */
case FNC_READH: /* read headers */
mbc = mba_get_bc (dibp->ba); /* get byte count */
mbc = rpxbc[drv] = mba_get_bc (dibp->ba); /* get byte count */
wc = (mbc + 1) >> 1; /* convert to words */
if ((da + wc) > drv_tab[dtype].size) { /* disk overrun? */
rp_set_er (ER1_AOE, drv); /* set err */
@ -1203,7 +1203,7 @@ else { /* Bottom End (After I/O processing) */
err = uptr->io_status;
switch (fnc) { /* case on function */
/* Functions having no Bottom since they are complete in the Top half */
case FNC_OFFSET: /* offset */
case FNC_RETURN: /* return to centerline */
case FNC_UNLOAD: /* unload */
@ -1211,13 +1211,14 @@ else { /* Bottom End (After I/O processing) */
case FNC_SEARCH: /* search */
case FNC_SEEK: /* seek */
case FNC_WRITEH: /* write headers stub */
abort (); /* should NEVER happen */
break;
case FNC_WRITE: /* write */
case FNC_WCHK: /* write check */
case FNC_READ: /* read */
case FNC_READH: /* read headers */
mbc = mba_get_bc (dibp->ba); /* get byte count */
mbc = rpxbc[drv]; /* get byte count */
wc = (mbc + 1) >> 1; /* convert to words */
if (fnc == FNC_WRITE) { /* write? */
} /* end if wr */