One of the things missing from asmLib is the ability to display the values of all of the registers and the flags to the screen. In this assignment you are going to get a chance to do exactly that.

You are to create a procedure called dumpRegisters that will dump the contents of each register to the screen. This includes the flags register and each independent flag. The output of your dumpRegisters procedure should look like this:

EAX: $5$afafc EBX: $9$db$000$ ECX: $5$ebdec EDX: $5$ebdec

ESI: $5$ebdec EDI: $5$ebdec EBP: $5$afab$0$ ESP: $5$afaa$8$

EIP: $763$afa$29$ EFL: $246$ CF$=0$ SF$=0$ ZF$=1$ OF$=0$ AF$=0$ PF$=1$

C:$\backslash$Users$\backslash$gstev$\backslash$source$\backslash$repos$\backslash$AsmProject$\backslash$AsmProject$\backslash$Debug$\backslash$AsmProject$.$exe $($process $3468)$ exited with code $0.$

Press any key to close this window $...$

Notice the use of the tab macro?

On the surface this seems like an easy chore for the most part but you need to be careful how you save and restore the registers. Remember these registers should match what is shown in the registers window of the debugger.

Review Debugger

If you need a review of the debugger and some information on flags and registers you should take a look at the review on this page.

Some Hopefully Helpful Things

You should have your dumpRegisters procedure call a procedure called showRegister. You want to pass the name of the register along with the value of the register to be displayed. I found that it was probably best to use invoke for this. My prototype looks like this:

showRegister PROTO,

regName:PTR BYTE $,$ regValue:DWORD

Displaying each value of the flags register is probably the most difficult thing here. Because it is I am going to provide a macro that you can use to make the chore easier:

ShowFlag MACRO flagName,shiftCount

LOCAL flagStr, flagVal, L$1$

$.$data

flagStr BYTE" &flagName$="$

flagVal BYTE?,$0$

$.$code

push eax

push edx

mov eax,eflags ; retrieve the flags

mov flagVal,$\text{'}1\text{'}$

shr eax,shiftCount ; shift into carry flag

jc L$1$

mov flagVal,$\text{'}0\text{'}$

L$1$:

mov edx,OFFSET flagStr ; display flag name and value

call WriteString

pop edx

pop eax

ENDM

To use this you can simply call showFlag, the flag to show and its bit position. You also need to define eflags which is a DWORD variable and should be located in the data segment of main. Here is an example call

ShowFlag CF$,1$

This shows the carry flag at bit $1$

You can use global variables here as needed but you really must pass parameters to the showRegister procedure.