Intel 80287 - Page 315

THE 80286 INSTRUCTION SET
STO"";'Set Direction Flag
Opcode Instruction
Clocks Description
FO STO
2 Set direction flag 50 51 and 01 will decrement
FLAGS MODIFIED
Direction = 1
FLAGS UNDEFINED
None
OPERATION
The direction flag is set to 1. This causes all subsequent string operations to decrement the index
registers (SI and/or 01)
on which they operate.
PROTECTED MODE EXCEPTIONS
None
REAL ADDRESS MODE EXCEPTIONS
None
8-105
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