Specifications

Operating System Routines
IOC$ALOALTMAP, IOC$ALOALTMAPN, IOC$ALOALTMAPSP
IOC$ALOALTMAP, IOC$ALOALTMAPN, IOC$ALOALTMAPSP
Allocate a set of Q22–bus alternate map registers.
Module
[SYSLOA]MAPSUBxxx
Input
Location Contents
R3 Number of alternate map registers to allocate
(IOC$ALOALTMAPN and IOC$ALOALTMAPSP
only). The value should account for one extra
register needed to prevent a transfer overrun.
R4 Number of first alternate map register to allocate
(IOC$ALOALTMAPSP only).
R5 Address of UCB.
UCB$W_BCNT Transfer byte count (IOC$ALOALTMAP only).
UCB$W_BOFF Byte offset in page (IOC$ALOALTMAP only).
UCB$L_CRB Address of CRB.
CRB$L_INTD+
VEC$L_ADP
Address of ADP.
CRB$L_INTD+
VEC$W_MAPALT
VEC$V_ALTLOCK set indicates that alternate map
registers have been permanently allocated to this
controller.
ADP$W_MR2NREGAR,
ADP$W_MR2FREGAR,
ADP$L_MR2ACTMDR
Alternate map register descriptor arrays.
Output
Location Contents
R0 SS$_NORMAL, SS$_INSFMAPREG, or
SS$_SSFAIL
R1 Destroyed
R2 Address of ADP
CRB$L_INTD+
VEC$W_NUMALT
Number of alternate map registers allocated
CRB$L_INTD+
VEC$W_MAPALT
Starting alternate map register number
ADP$W_MR2NREGAR,
ADP$W_MR2FREGAR,
ADP$L_MR2ACTMDR
Updated
3–71