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Chapter 17 -- 80386 Instruction Set
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STD -- Set Direction Flag
Opcode Instruction Clocks Description
FD STD 2 Set direction flag so (E)SI and/or (E)DI
decrement
Operation
DF := 1;
Description
STD sets the direction flag to 1, causing all subsequent string operations
to decrement the index registers, (E)SI and/or (E)DI, on which they
operate.
Flags Affected
DF := 1
Protected Mode Exceptions
None
Real Address Mode Exceptions
None
Virtual 8086 Mode Exceptions
None
up:
Chapter 17 -- 80386 Instruction Set
prev: STC Set Carry Flag
next: STI Set Interrupt Flag