Technical data

SDA Description
Table SDA–9 (Cont.) SDA Symbols
Symbol Meaning
nnDRIVER Base address of a driver prologue table (DPT); such a symbol exists
for each loaded device driver in the system
3
ESP Executive stack pointer
2
FP Frame pointer
2
FPEMUL Base address of the code that emulates floating-point instructions
G 80000000
16
, the base address of system space
H 7FFE0000
16
IRP Address of I/O request packet
1
JIB Job information block
KSP Kernel stack pointer
2
LNM Address of logical name block for mailbox
1
MCHK Address within loadable CPU-specific routines
MSCP Address of loadable MSCP server code
ORB Address of object rights block
1
P0BR Base register for the program region (P0)
2
P0LR Length register for the program region (P0)
2
P1BR Base register for the control region (P1)
2
P1LR Length register for the control region (P1)
2
PC Program counter
2
PCB Process control block
PDT Address of port descriptor table
1
PHD Process header
PSL Processor status longword
2
R0 through R11 General registers
2
RMS Base address of the RMS image
RWAITCNT Resource wait count for MSCP-served device
1
SB Address of system block
1
SCSLOA Base address of loadable common SCS services
SP Current stack pointer of a process
2
SSP Supervisor stack pointer
2
SYSLOA Base address of loadable processor-specific system code
TMSCP Address of loadable TMSCP server code
UCB Address of unit control block
1
1
The SHOW DEVICE command defines this symbol, if appropriate, to represent information pertinent
to the last displayed device unit. See the description of the SHOW DEVICE command for additional
information.
2
The value of those symbols representing the current SDA process context changes whenever you
issue a command that changes the context (see Section 4). These symbols include the general-purpose
registers (R0 through R11, AP, FP, PC, and SP); the per-process stack pointers (USP, SSP, KSP);
the page table base and length registers (P0BR, P0LR, P1BR, and P1LR); and the processor status
longword (PSL).
3
The notation nn within the symbol nnDRIVER represents a 2-letter, generic device/controller name
(for example, LPDRIVER).
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SDA–18