Intel 64 and IA-32 Architectures Software Developers Manual Volume 2B, Instruction Set Reference, N-Z

4-20 Vol. 2B
INSTRUCTION SET REFERENCE, N-Z
ELSE (* 32-Bit Address Size *)
IF DF
= 0
THEN ESI ← ESI + 2;
ELSE ESI ← ESI – 2;
FI;
FI;
ELSE
IF DF
= 0
THEN (E)SI ← (E)SI + 2;
ELSE (E)SI ← (E)SI – 2;
FI;
FI;
Doubleword transfer:
IF 64-bit mode
Then
IF 64-Bit Address Size
THEN
IF DF
= 0
THEN RSI ← RSI RSI + 4;
ELSE RSI ← RSI or – 4;
FI;
ELSE (* 32-Bit Address Size *)
IF DF
= 0
THEN ESI ← ESI + 4;
ELSE ESI ← ESI – 4;
FI;
FI;
ELSE
IF DF
= 0
THEN (E)SI ← (E)SI + 4;
ELSE (E)SI ← (E)SI – 4;
FI;
FI;
Flags Affected
None.
Protected Mode Exceptions
#GP(0) If the CPL is greater than (has less privilege) the I/O privilege
level (IOPL) and any of the corresponding I/O permission bits in
TSS for the I/O port being accessed is 1.