Register: R [register] Entering ' r ' all by itself will display all of the 8086 register's contents and the next instruction which the IP register points to in both machine code and an unassembled (Assembly Language) form. For example, if you start DEBUG in a Windows 95B DOS-box with the command line: >debug c:\windows\command\choice.comand then enter an ' r ' at the first DEBUG prompt, DEBUG will display someting similar to this:AX=0000 BX=0000 CX=1437 DX=0000 SP=FFFE BP=0000 SI=0000 DI=0000DS=0ED8 ES=0ED8 SS=0ED8 CS=0ED8 IP=0100 NV UP EI PL NZ NA PO NC0ED8:0100 E90E01 JMP 0211For an explanation of the names of the registers (AX, BX, CX, etc. and the Flag symbols: NV UP EI PL NZ NA PO NC), see the Appendix (The 8086 CPU Registers). The last line shows that the next CPU instruction (actually the first in this case) to be executed, begins at memory location 100 hex (the Offset) in Segment ED8 hex (0ED8:0100) and that the Hex bytes E90E01 represent the actual binary machine code of the CPU instruction (JMP 0211 in Assembly language) that would be executed by DEBUG if you entered a Trace (t) or Proceed (p) command.If you enter the ' r ' followed by the abbreviation for an 8086 register, such as: ' rcx ', then DEBUG will display only the contents of that register followed by a line with a colon symbol (:) on which you can enter a hex number to change the contents of that register. If you simply press the ENTER key, the contents remain the same. For example: -rcx CX 0100 :273 means that the Register command was used to change the contents of the CX register from 0100 to 0273. The command ' rcx ' could be used again to verify that the change had indeed taken place. If you type the letter f after an r: ' rf ', this commands DEBUG to display all of the FLAG register bits with a prompt on the same line which allows you to change any or none of the individual flag bits. For example, here's how you would display the flags and change just the Zero Flag bit from being cleared (a 0 bit) to being set (a 1 bit): -rf NV UP EI PL NZ NA PO NC -zr -rf NV UP EI PL ZR NA PO NC - -As you can see above the Zero Flag was changed from NZ (cleared) to ZR (set). See the Appendix The FLAGS Register below for an explanation of all the Flag abbreviations.