HP Vectra Technical Reference Manual page 67

4.2.2 Data Structures
The application interface level uses two major data structures: the Logical Describe Record and
the Logical ISR Event Record(s). These data structures help keep track of the numerous events
occurring in the Input System.
4.2.2.1 Logical Describe Record
The Logical Describe Record is used by the logical GID drivers to keep track of the current state
of their respective devices. Each of the logical GID drivers has a Logical Describe Record
associated with it, which is located directly after the driver header starting with memory address
DS:001 OH. An explanation of the Logical Describe Record fields follows, see table 4.1 for field
types and offsets.
Table 4.1
Logical GID Driver Describe Record
Field Type Offset Description
Driver Header
OOH
Driver Header (see Section 2)
LD_SOURCE BYTE
10H
Device GID type
LD_HPHILID BYTE
11H
Physical device ID
LD_DEVICE_STATE
WORD
12H
Status bits for the logical device
LD_INDEX
BYTE
14H
Physical device vector number
LD_MA>LAXIS BYTE
15H
Maximum number of axes reported
LD_CLASS BYLE
16H
Device class
LD_PROMPTS
BYTE
17H
Number of button/prompts
LD_RESERVED BYTE
18H-1BH
Reserved
LD_TRANSITION BYTE
1CH
Button transitions
LD_STATE BYTE
1DH
Current state of the buttons
LD_RESOLUTION WORD
1EH
Logical device resolution
LD_SIZE-X WORD
20H
Maximum x-axis count
LD_SIXE_Y WORD
22H
Maximum y-axis count
LD--.ABS-X WORD
24H
X position data for absolute devices
LD--.ABS_Y
WORD
26H
Y position data for absolute devices
LD_RELX WORD
28H
X delta for relative devices
LD_RELY WORD
2AH
Y
delta for relative devices
LD--.ACCU M-X
WORD
2CH
X-axis scaling accumulator
LD--.ACCUM_Y WORD
2EH
Y-axis scaling accumulator
58 Input System and HP-HIL