Compatibility Notes A.16

INC, DEC, ADD, SUB.

If the operand data contains undigits other than in the sign digit, incompatible results may be produced.

B4800 Undigits in arithmetic data other than the sign or zone digits are not detected as an error.
B2900
B3900
Undigits in arithmetic data other than the sign or zone digits are detected as errors. The entire field containing the invalid undigits remains unchanged. The processor reports the address of the instruction in error. The Overflow Flag is always set.
B4900 Undigits in arithmetic data other than the sign or zone digits are detected as errors. If the operand in error is also written (i.e. INC), the operand may be partially overwritten with the new result but the detected undigits will still be present. The processor reports the address of the instruction in error. The Overflow Flag is not affected.
Note that an overflow condition can be detected before any undigit check is performed. In such case, the Overflow Flag is set and no undigit in data is reported even if undigit in data condition exists.
V300
V500
Undigits in arithmetic data other than the sign or zone digits are detected as errors. If the operand in error is also written (i.e. INC), the operand may be partially overwritten with the new result but the detected undigits will still be present. The processor reports the address of the instruction in error. The Overflow Flag is not affected.
compatibility_notes/a.16.txt · Last modified: 2008/05/13 07:22 (external edit)
 
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