Some sort of progress on deciphering the CHAR(2) "resulting condition
information" in the Body section you described Simon:
Body section:
CHAR(8) op-code name
CHAR(2) op-code number
CHAR(3) flags
CHAR(1) optional instruction forms
CHAR(2) possibly resulting condition information
Per the Information Centre, branch and indicator keywords are divided into
four groups:
Group 1
HI MXD NOR POS TR ZC
Group 2
CR DEN IGN LO NEG NTZNTC RO
Group 3
AUTH DFR DQ EQ INF SE SGN ZER ZNTC
Group 4
EC NAN NTZC UNEQ UNOR
The first byte appears to indicate which groups are valid for the op-code:
Bit 0: Group 1
Bit 1: Group 2
Bit 3: Group 3
Bit 6: Group 4
The corresponding bits in the second byte appear to denote whether the
condition can be negated. This would explain why the second byte is
b'00000000' for the SIGEXCP op-code as keywords IGN and DFR cannot be
negated.
Best wishes,
Richard
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