The CPU has four general-purpose registers called AL, BL, CL and DL. These are eight bits or one byte wide. Registers can hold unsigned numbers in the range 0 to +255 and signed numbers in the range –128 to +127. These are used as temporary storage locations. Registers are used in preference to RAM locations because it takes a relatively long time to transfer data between RAM and the CPU. Faster computers generally have more CPU registers or memory on the CPU chip.
The registers are named AL, BL, CL and DL because the 16-bit version of this CPU has more registers called AH, BH, CH and DH. The 'L' means Low and the 'H' means High. These are the low and high ends of the 16-bit register.
Share with your friends: |
