CPU Register - DF Control Flag

> Computer System > Computer - Central processing unit (CPU) > Processor - (Execution) Register

1 - About

The direction flag (DF, located in bit 10 of the EFLAGS register) controls string instructions.

3 - Management

3.1 - Set

Setting the DF flag causes the string instructions to auto-decrement (to process strings from high addresses to low addresses).

3.2 - Clear

Clearing the DF flag causes the string instructions to auto-increment (process strings from low addresses to high addresses). The STD and CLD instructions set and clear the DF flag, respectively.

Advertising