Intel Pentium CPU Instruction Set Reference
STD instruction - Set Direction Flag
| Code |
Mnemonic |
Description |
| FD |
STD |
Set DF flag |
Description
Sets the DF flag in the EFLAGS register. When the DF flag is set to 1, string operations decrement the index registers (ESI and/or EDI).
| Operands |
Bytes |
Clocks |
|
1 |
2 |
NP |
Flags
| ID |
unaffected |
DF |
sets |
| VIP |
unaffected |
IF |
unaffected |
| VIF |
unaffected |
TF |
unaffected |
| AC |
unaffected |
SF |
unaffected |
| VM |
unaffected |
ZF |
unaffected |
| RF |
unaffected |
AF |
unaffected |
| NT |
unaffected |
PF |
unaffected |
| IOPL |
unaffected |
CF |
unaffected |
| OF |
unaffected |
