16 bit registers

• AX ... accumulator
• CX ... counter
• DX ... data
• BX ... base
• SP ... stack pointer
• BP ... base pointer
• SI ... source index
• DI ... destination index

8 bit registers

• AL ... accumulator low
• CL ... counter low
• DL ... data low
• BL ... base low
• AH ... accumulator high
• CH ... counter high
• DH ... data high
• BH ... base high

segment registers

• ES ... extra segment
• CS ... code segment
• SS ... stack segment
• DS ... data segment
• FS ... dummy segment
• GS ... dummy segment