Assembly  Links

ADC - Add with Carry
ADD - Add
AND - Bitwise AND
CALL - Call Routine
CLC - Clear Carry Flag
CLD - Clear Direction
CLI - Clear Interupt Flag
CMPS - Compare
CMP - Compare
DEC - Decrement
DIV - Divide
HLT - Halt
IDIV - Divide Signed
IMUL - Multiply Signed
INC - Increment
INS - Input
INT - Interupt
IN - Input
IRET - Interupt Return
JMP - Jump
J - Jump Conditional
LAHF - Load Flags
LDS - Load Far Pointer
LEA - Store Address
LES - Load Far Pointer
LFS - Load Far Pointer
LGS - Load Far Pointer
LODSB - LODSW - Load
LODS - Load
LOOP - Loop
LSS - Load Far Pointer
MOVSB - Move Far
MOVSW - Move Far
MOVS - Move
MOV - Move
MUL - Multiply
NEG - Negate
NOP - No Operation
NOT - Bitwise NOT
OR - Bitwise OR
OUTS - Output
OUT - Output
POP - Stack Retrieval
PUSH - Stack Store
RCL - Roll Left
RCR - Roll Right
REP - Repeat
RET - Return
ROL - Roll Left
ROR - Roll Right
SAHF - Save Flags
SAL - Shift Left
SAR - Shift Right
SBB - Subtract with Borrow
SCAS - Compare
SET - Set Condition
SHL - Shift Left
SHR - Shift Right
STC - Set Carry Flag
STD - Set Direction
STI - Set Interupt Flag
STOSB - STOSW - Store
STOS - Store
SUB - Subtract
TEST - Compare
XADD - Exchange and And
XCHG - Swap
XOR - Bitwise XOR

STD  -  Set Direction Instruction

The STD instruction is used to set the DF flag. This effects the direction in which data is read using the SI and DI registers.

When Set the SI and DI registers are decremented, when the flag is cleared using CLD instruction they are incremented.

STD Op Code is FD to set flag to 1

CLD Op Code is FC to clear flag to 0