Understanding in variables in Assembly

CS Code Segment 16-bit number that points to the active code-segment

DS Data Segment 16-bit number that points to the active data-segment

SS Stack Segment 16-bit number that points to the active stack-segment

ES Extra Segment 16-bit number that points to the active extra-segment Pointer Registers
IP Instruction Pointer 16-bit number that points to the offset of the next instruction

SP Stack Pointer 16-bit number that points to the offset that the stack is using

BP Base Pointer used to pass data to and from the stack General-Purpose Registers
AX Accumulator Register mostly used for calculations and for input/output

BX Base Register Only register that can be used as an indexCX Count Register register used for the loop instruction

DX Data Register input/output and used by multiply and divide Index Registers
SI Source Index used by string operations as sourceDI Destination Index used by string operations as destination Flags Register Abr. Name bit nº Description
OF Overflow Flag 11 indicates an overflow when set

DF Direction Flag 10 used for string operations to check direction

IF Interrupt Flag 9 if set, interrupt are enabled, else disabled

TF Trap Flag 8 if set, CPU can work in single step modeSF Sign Flag 7 if set, resulting number of calculation is negative

ZF Zero Flag 6 if set, resulting number of calculation is zero

AF Auxiliary Carry 4 some sort of second carry flag

PF Parity Flag 2 indicates even or odd parity

CF Carry Flag 0 contains the left-most bit after calculations