Technical data

SDA Description
Figure SDA–2 Mechanism Array
00000004
ZK−1921−GE
Frame
Depth
R0
R1
The values in the mechanism array are the following:
Value Meaning
00000004 Number of longwords that follow. In a mechanism array, this value is
always 4.
Frame Address of the FP (frame pointer) of the establisher’s call frame.
Depth Depth of the search for a condition handler.
R0 Contents of R0 at the time of the exception.
R1 Contents of R1 at the time of the exception.
The signal array (see Figure SDA–3) appears somewhat further down the stack.
A signal array contains the exception code, zero or more exception parameters,
the PC, and the PSL. The size of a signal array can thus vary from exception to
exception.
Figure SDA–3 Signal Array
00000005
ZK−1922−GE
0000000C
Reason Mask
Virtual Address
PC
PSL
SDA–22