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80386 Programmer's Reference Manual -- Opcode STD

STD -- Set Direction Flag

Opcode	Instruction	Clocks	Description	Example
FD	std	2	Set direction flag so (E)SI and/or (E)DI decrement	`std`

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

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